WO2023245078A1 - Anti-parvovirus antibodies and uses thereof - Google Patents

Abstract

The instant disclosure provides antibodies and antigen-binding fragments thereof that can bind to parvovirus,e.g. parvovirus B19 and can neutralize a parvovirus infection. Also provided are polynucleotides that encode an antibody, vectors that comprise such polynucleotides, host cells that can express the antibodies, related compositions, and methods of using the herein disclosed compositions to, for example, treat or prevent a parvovirus infection.

Description

ANTI-PARVOVIRUS ANTIBODIES AND USES THEREOF

REFERENCE TO AN ELECTRONIC SEQUENCE LISTING

The contents of the electronic sequence listing (440WO_SeqListing.xml; Size: 53 kilobytes; and Date of Creation: June 12, 2023) is herein incorporated by reference in its entirety.

BACKGROUND

Discovered in 1975, parvovirus B19 is one of the only members of the Parvoviridae family infecting humans. In addition to the common childhood disease erythema infectiosum, the B 19 virus is also associated with more severe diseases, including hydrops fetalis and fetal death, aplastic crises, polyarthralgia and arthritis and pure red-cell aplasia. The current treatment for patients suffering from persistent B 19 virus infection is administration of human immunoglobulin preparations, e.g., intravenous immunoglobulin therapy (IVIG), which have limited efficacy and toxicity risks. Human immunoglobulins are also scarce, as it is challenging to find human donors, and costly. The use of non-human, animal immunoglobulins (e.g., equine) is affected by challenges such as a limited production, animal welfare concerns, and safety issues.

Thus, there is a need for more effective and practical modalities for treating parvovirus infections.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows results of stimulated B cells from healthy donor tonsils screened for binding to VPl/VP2-expressing VLPs. 43% of the tonsil donors scored positive and 3 were selected for isolation of monoclonal antibodies (mAbs) (outlined).

Figure 2A-2D show results of an immunodominance study in antigen-specific B-cell memory repertoire analysis (AMBRA) supernatants and different collections of sera. Figure 2A shows frequency of positivity from AMBRA supernatants on VP1/VP2 and VP2 virus-like particles (VLPs). Figures 2B-2C show endpoint VP 1 vs VP2 from 60 sera collected in Bologna, Italy (Figure 2B) or 111 sera collected in Bellinzona, Switzerland (Figure 2C). Antibody values were expressed as endpoint titers defined as the highest dilution at which the OD was higher than twice the background OD. Figure 2D shows inhibition of competition in sera collected in Bellinzona with PAB5 (VP1) biotinylated vs PAB18 (VP2) biotinylated.

Figures 3A-3D show characterization of selected mAbs. Figure 3A provides a table showing parvovirus neutralization activity of mAb, the light chain isotype of as mAb determined by enzyme-linked immunosorbent assay (ELISA), the germline usage for V-D-J (VH) and V-J (VL) genes defined using the ImMunoGeneTics information system (IMGT) database and result of Western blot binding to reduced and non-reduced antigen. Figures 3B-3D show binding of various mAbs isolated from immortalized IgG+ memory B cells as assessed by ELISA. Figure 3B shows mAbs binding exclusively to VP1/VP2 VLPs (z.e., VPl-specific) (PAC24=PAC24.1 is not recombinant). Figure 3C shows mAbs binding to VP1/VP2 and VP2 VLPs (z.e., VP2- specific) (PAC57, PAC58, and PAC69 are not recombinant). Figure 3D shows IgG and Fab of PAB5 mAb binding to VP1/VP2 VLPs.

Figures 4A-4C show results from comparison of binding and blockade of binding studies (BOB). Figure 4A shows binding of IVIG, PAB5 and PAB18 mAbs to VP1/VP2 VLPs by ELISA. Blockade of binding of labeled PAB5 (Figure 4B) or PAB18 (Figure 4C) mAbs to VP1/VP2 VLPs by different concentrations of unlabeled PAB5, PAB18, and IVIG.

Figures 5A-5E show results from cross-competition studies and epitope mapping. Figure 5A shows cross-competition studies of anti-VPl mAbs against biotinylated anti-VPl mAbs. Figure 5B shows cross-competition studies of anti-VP2 mAbs against biotinylated anti-VP2 mAbs. Figure 5C shows an intensity plot with averaged spot intensities of PAB5-rIgGl (lOpg/ml) on a conformational peptide microarray containing 696 different cyclic constrained peptides. Figure 5D shows an intensity plot with averaged spot intensities of PAA19-rIgGl (500 pg/ml) on a conformational peptide microarray containing 1,677 different cyclic constrained peptides. The intensity plots were correlated with peptide and intensity maps as well as with visual inspection of the microarray scans to identify the epitopes of the human mAbs. In case it was not clear if a certain amino acid contributed to antibody binding, the corresponding letter was written in gray (lighter font). Figure 5E shows an amino acid plot of PAB5-rIgGl against the microarray containing conformational peptides with 119 variants of the wild type peptide: the plot was calculated by dividing the spot intensity of a given peptide (e.g.,¹YPYDVQDYA⁹ (SEQ ID NO.:44)) by the spot intensity of the native epitope (¹YPYDVPDYA⁹ (SEQ ID NO.:45)). The position of an amino acid at a given position, thus, reflected the intensity ratio compared to the wild type amino acid at the same position.

Figures 6A-6C show data on neutralization of B 19 by selected VP1 and VP2 mAbs. Figure 6A shows fluorescence-activated cell sorting (FACS) data on EPC primary cells. Figure 6B shows percentage neutralization by the selected VP1 and VP2 mAbs. Figure 6C shows qPCR data on EPC primary cells. “Grifols” = anti-parvovirus immune globulin preparation (for intravenous administration (IVIG)) from Grifols Pharmaceutical.

Figure 7 shows modeled structures of VP1 receptor-binding domain (RBD) having different mutations.

Figures 8A-8C show amino acid sequences and certain polynucleotide sequences for variable domains of anti-parvovirus antibodies PAB18 (8A), PAB5 (8B), and PAA19 (8C).

Figures 9A-9C show neutralization of infection by antibodies and by an antibody combination, as described in Example 6. Figures 9A and 9B show results from different concentrations of antibodies. Figure 9C shows results from antibodies, antibody Fabs, or combinations, at lug/ml of antibody, Fab, or combination.

Figures 10A-10B show neutralization of infection (IC80, ug/ml shown as foldchange vs. IVIG) by antibodies PAB5, PAA19, and PAB18, and by PAB5 Fab, as described in Example 6. “Grifols” = anti-parvovirus immune globulin preparation (for intravenous administration (IVIG)) from Grifols Pharmaceutical. Figure 11 shows titers of VPl/VP2-specific and VP2-specific antibodies in sera from human patients with chronic parvovirus B19 infection (left) and from healthy human donors (right). Endpoint VP 1 vs VP2 from antibody values were expressed as endpoint titers defined. as the highest dilution at which the OD was higher than twice the background OD. These data illustrate that most anti -parvovirus antibodies in sera are directed to B19 VP2.

Figure 12 shows results from AMBRA analysis of human tonsil samples, illustrating that antibody response against B 19 VP1 is rare. The bottom graph shows frequency of positivity from AMBRA supernatants on VP1 and VP2 (tonsils T 1-2- 12- 21-24-26-28-32-36).

DETAILED DESCRIPTION

Provided herein are antibodies and antigen-binding fragments that can bind to and, in certain embodiments, can potently neutralize infection by parvovirus, such as parvovirus Bl 9. In some embodiments, a fragment antigen-binding (Fab) of an antibody or antigen-binding fragment is sufficient for potent neutralization of infection by a parvovirus, such as parvovirus Bl 9. Also provided are polynucleotides that encode the antibodies and antigen-binding fragments, vectors, host cells, and related compositions, as well as methods of using the antibodies, polynucleotides, vectors, host cells, and related compositions to treat (e.g., reduce, delay, eliminate, or prevent) and/or to diagnose a parvovirus infection in a subject and/or in the manufacture of a medicament for treating a parvovirus infection in a subject.

Non-limiting examples of anti-parvovirus antibodies of the present disclosure include the human antibodies “PAB5”, PAA19”, and “PAB18”. As provided herein, PAB5 is a potent neutralizing antibody that binds in a conserved region of B19 uVPl. PAA19 and PAB18 are also neutralizing antibodies and bind to distinct antigenic sides in VP2.

Some embodiments provide an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAB5. Some embodiments provide an antibody or antigenbinding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAA19. Some embodiments provide an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAB18. Also provided are antibodies and antigen-binding fragments comprising one or more CDR, one or more variant CDR, and/or one or more other variations in a VH and/or in a VL, relative to PAB5, PAA19, or PAB18.

In certain embodiments, a composition or combination is provided that comprises two or more different presently disclosed antibodies or antigen-binding fragments. For example, some embodiments provide a composition or combination comprising: (i) an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAB5, and (ii) an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAA19.

Certain other embodiments provide a composition or combination comprising: (i) an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAB5, and (ii) an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAB18.

Certain other embodiments provide a composition or combination comprising: (i) an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAB18, and (ii) an antibody or antigen-binding fragment comprising the six CDRs, and optionally comprising the VH and VL amino acid sequences, of antibody PAA19.

Some embodiments include a method of treating and/or preventing a parvovoirus infection, wherein a herein described combination or composition comprising two or more different antibodies or antigen-binding fragments is administered to a subject. In certain embodiments, an antibody or antigen-binding fragment comprises a heavy chain and the heavy chain comprises one or more mutations for extending in vivo half-life (e.g., in a human) of the antibody or antigen-binding fragment. For example, in some embodiments, a heavy chain comprises the mutations M428L and N434S (EU numbering).

Prior to setting forth this disclosure in more detail, it may be helpful to an understanding thereof to provide definitions of certain terms to be used herein. Additional definitions are set forth throughout this disclosure.

In the present description, any concentration range, percentage range, ratio range, or integer range is to be understood to include the value of any integer within the recited range and, when appropriate, fractions thereof (such as one tenth and one hundredth of an integer), unless otherwise indicated. Also, any number range recited herein relating to any physical feature, such as polymer subunits, size or thickness, are to be understood to include any integer within the recited range, unless otherwise indicated. As used herein, the term "about" means ± 20% of the indicated range, value, or structure, unless otherwise indicated. It should be understood that the terms "a" and "an" as used herein refer to "one or more" of the enumerated components. The use of the alternative (e.g., "or") should be understood to mean either one, both, or any combination thereof of the alternatives. As used herein, the terms "include," "have," and "comprise" are used synonymously, which terms and variants thereof are intended to be construed as non-limiting.

"Optional" or "optionally" means that the subsequently described element, component, event, or circumstance may or may not occur, and that the description includes instances in which the element, component, event, or circumstance occurs and instances in which they do not.

In addition, it should be understood that the individual constructs, or groups of constructs, derived from the various combinations of the structures and subunits described herein, are disclosed by the present application to the same extent as if each construct or group of constructs was set forth individually. Thus, selection of particular structures or particular subunits is within the scope of the present disclosure. The term "consisting essentially of is not equivalent to "comprising" and refers to the specified materials or steps of a claim, or to those that do not materially affect the basic characteristics of a claimed subject matter. For example, a protein domain, region, or module (e.g., a binding domain) or a protein "consists essentially of' a particular amino acid sequence when the amino acid sequence of a domain, region, module, or protein includes extensions, deletions, mutations, or a combination thereof (e.g., amino acids at the amino- or carboxy -terminus or between domains) that, in combination, contribute to at most 20% (e.g., at most 15%, at most 10%, at most 8%, at most 6%, at most 5%, at most 4%, at most 3%, at most 2% or at most 1%) of the length of a domain, region, module, or protein and do not substantially affect (i.e., do not reduce the activity by more than 50%, such as no more than 40%, no more than 30%, no more than 25%, no more than 20%, no more than 15%, no more than 10%, no more than 5%, or no more than 1%) the activity of the domain(s), region(s), module(s), or protein (e.g., the target binding affinity of a binding protein).

As used herein, "amino acid" refers to naturally occurring and synthetic amino acids, as well as amino acid analogs and amino acid mimetics that function in a manner similar to the naturally occurring amino acids. Naturally occurring amino acids are those encoded by the genetic code, as well as those amino acids that are later modified, e.g., hydroxyproline, y-carboxyglutamate, and O-phosphoserine. Amino acid analogs refer to compounds that have the same basic chemical structure as a naturally occurring amino acid, i.e., an a-carbon that is bound to a hydrogen, a carboxyl group, an amino group, and an R group, e.g., homoserine, norleucine, methionine sulfoxide, methionine methyl sulfonium. Such analogs have modified R groups (e.g., norleucine) or modified peptide backbones, but retain the same basic chemical structure as a naturally occurring amino acid. Amino acid mimetics refer to chemical compounds that have a structure that is different from the general chemical structure of an amino acid, but that functions in a manner similar to a naturally occurring amino acid.

As used herein, "mutation" refers to a change in the sequence of a nucleic acid molecule or polypeptide molecule as compared to a reference or wild-type nucleic acid molecule or polypeptide molecule, respectively. A mutation can result in several different types of change in sequence, including substitution, insertion or deletion of nucleotide(s) or amino acid(s).

A "conservative substitution" refers to amino acid substitutions that do not significantly affect or alter binding characteristics of a particular protein. Generally, conservative substitutions are ones in which a substituted amino acid residue is replaced with an amino acid residue having a similar side chain. Conservative substitutions include a substitution found in one of the following groups: Group 1 : Alanine (Ala or A), Glycine (Gly or G), Serine (Ser or S), Threonine (Thr or T); Group 2: Aspartic acid (Asp or D), Glutamic acid (Glu or Z); Group 3 : Asparagine (Asn or N), Glutamine (Gin or Q); Group 4: Arginine (Arg or R), Lysine (Lys or K), Histidine (His or H); Group 5: Isoleucine (He or I), Leucine (Leu or L), Methionine (Met or M), Valine (Vai or V); and Group 6: Phenylalanine (Phe or F), Tyrosine (Tyr or Y), Tryptophan (Trp or W). Additionally or alternatively, amino acids can be grouped into conservative substitution groups by similar function, chemical structure, or composition (e.g., acidic, basic, aliphatic, aromatic, or sulfur-containing). For example, an aliphatic grouping may include, for purposes of substitution, Gly, Ala, Vai, Leu, and He. Other conservative substitutions groups include: sulfur-containing: Met and Cysteine (Cys or C); acidic: Asp, Glu, Asn, and Gin; small aliphatic, nonpolar or slightly polar residues: Ala, Ser, Thr, Pro, and Gly; polar, negatively charged residues and their amides: Asp, Asn, Glu, and Gin; polar, positively charged residues: His, Arg, and Lys; large aliphatic, nonpolar residues: Met, Leu, He, Vai, and Cys; and large aromatic residues: Phe, Tyr, and Trp. Additional information can be found in Creighton (1984) Proteins, W.H. Freeman and Company.

As used herein, "protein" or "polypeptide" refers to a polymer of amino acid residues. Proteins apply to naturally occurring amino acid polymers, as well as to amino acid polymers in which one or more amino acid residue is an artificial chemical mimetic of a corresponding naturally occurring amino acid, and non-naturally occurring amino acid polymers. Variants of proteins, peptides, and polypeptides of this disclosure are also contemplated. In certain embodiments, variant proteins, peptides, and polypeptides comprise or consist of an amino acid sequence that is at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.9% identical to an amino acid sequence of a defined or reference amino acid sequence as described herein. In some embodiments, a variant polypeptide (e.g. antibody or antigen-binding fragment) comprises one or more substitutions, one or more of which is optionally a conservative substitution and/or is a substitution to a germline-encoded amino acid (see Figure 3 A for VH germline gene usage of certain antibodies fo the present disclosure).

Any polypeptide of this disclosure (e.g., VH, VL, Fab, Fd, antibody heavy chain, antibody light chain) can, as encoded by a polynucleotide sequence, comprise a “signal peptide” (also known as a leader sequence, leader peptide, or transit peptide). Signal peptides target newly synthesized polypeptides to their appropriate location inside or outside the cell. A signal peptide may be removed in whole or in part from the polypeptide during or once localization or secretion is completed. Polypeptides that have a(n, e.g., full-length) signal peptide can be referred to as a “pre-protein” and polypeptides having their signal peptide removed - at least in part - can be referred to as “mature” proteins or polypeptides. In certain embodiments, an antibody or antigenbinding fragment is a mature protein or a pre-protein.

"Nucleic acid molecule" or "polynucleotide" or "polynucleic acid" refers to a polymeric compound including covalently linked nucleotides, which can be made up of natural subunits (e.g., purine or pyrimidine bases) or non-natural subunits (e.g., morpholine ring). Purine bases include adenine, guanine, hypoxanthine, and xanthine, and pyrimidine bases include uracil, thymine, and cytosine. Nucleic acid molecules include polyribonucleic acid (RNA), which includes mRNA, microRNA, siRNA, viral genomic RNA, and synthetic RNA, and polydeoxyribonucleic acid (DNA, also referred to as deoxyribonucleic acid), which includes cDNA, genomic DNA, and synthetic DNA, either of which may be single or double stranded. If single-stranded, the nucleic acid molecule may be the coding strand or non-coding (anti-sense) strand. A nucleic acid molecule encoding an amino acid sequence includes all nucleotide sequences that encode the same amino acid sequence. Some versions of the nucleotide sequences may also include intron(s) to the extent that the intron(s) would be removed through co- or post-transcriptional mechanisms. In other words, different nucleotide sequences may encode the same amino acid sequence as the result of the redundancy or degeneracy of the genetic code, or by splicing.

In some embodiments, the polynucleotide comprises a modified nucleoside, a cap-1 structure, a cap-2 structure, or any combination thereof. In certain embodiments, the polynucleotide comprises a pseudouridine, a N6-methyladenonsine, a 5- methylcytidine, a 2-thiouridine, or any combination thereof. In some embodiments, the pseudouridine comprises N1 -methylpseudouridine. These features are known in the art and are discussed in, for example, Zhang et al. Front. Immunol., DOI=10.3389/fimmu.2019.00594 (2019); Eyler et al. PNAS 116(46): 23068-23071; DOI: 10.1073/pnas.1821754116 (2019); Nance and Meier, ACS Cent. Set. 2021, 7, 5, 748-756; doi.org/10.1021/acscentsci. lc00197 (2021), and van Hoecke and Roose, J. Translational Med 17:54 (2019); https://doi.org/10.1186/sl2967-019-1804-8, which modified nucleosides and mRNA features are incorporated herein by reference. Variants of nucleic acid molecules of this disclosure are also contemplated. Variant nucleic acid molecules are at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, and are preferably at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.9% identical to a nucleic acid molecule of a defined or reference polynucleotide as described herein, or that hybridize to a polynucleotide under stringent hybridization conditions of 0.015M sodium chloride, 0.0015M sodium citrate at about 65-68°C or 0.015M sodium chloride, 0.0015M sodium citrate, and 50% formamide at about 42°C. Nucleic acid molecule variants retain the capacity to encode a binding domain thereof having a functionality described herein, such as binding a target molecule.

"Percent sequence identity" refers to a relationship between two or more sequences, as determined by comparing the sequences. Preferred methods to determine sequence identity are designed to give the best match between the sequences being compared. For example, the sequences are aligned for optimal comparison purposes (e.g., gaps can be introduced in one or both of a first and a second amino acid or nucleic acid sequence for optimal alignment). Further, non-homologous sequences may be disregarded for comparison purposes. The percent sequence identity referenced herein is calculated over the length of the reference sequence, unless indicated otherwise. Methods to determine sequence identity and similarity can be found in publicly available computer programs. Sequence alignments and percent identity calculations may be performed using a BLAST program e.g., BLAST 2.0, BLASTP, BLASTN, or BLASTX). The mathematical algorithm used in the BLAST programs can be found in Altschul et al., Nucleic Acids Res. 25:3389-3402, 1997. Within the context of this disclosure, it will be understood that where sequence analysis software is used for analysis, the results of the analysis are based on the "default values" of the program referenced. "Default values" mean any set of values or parameters which originally load with the software when first initialized. Other examples include Clustal W, MAFFT, Clustal Omega, AlignMe, Praline, GAP, BESTFIT, Needle (EMBOSS), Stretcher (EMBOSS), GGEARCH2SEQ, Water (EMBOSS), Matcher (EMBOSS), LALIGN, and SSEARCH2SEQ. A global alignment algorithm, such as a Needleman and Wunsch algorithm, can be used to align two sequences over their entire length, maximizing the number of matches and minimizes the number of gaps. Default values can be used.

To generate similarity scores for two amino acid sequences, scoring matrices can be used that assign positive scores for some non-identical amino acids (e.g., conservative amino acid substitutions, amino acids with similar physio-chemical properties, and/or amino acids that exhibit frequent substitutions in orthologs, homologs, or paralogs). Non-limiting examples of scoring matrices include PAM30, PAM70, PAM250, BLOSUM45, BLOSUM50, BLOUM62, BLOSUM80, and BLOSUM90.

Within the context of this disclosure, it will be understood that where sequence analysis software is used for analysis, the results of the analysis are based on the “default values” of the program referenced. “Default values” mean any set of values or parameters which originally load with the software when first initialized. The term "isolated" means that the material is removed from its original environment (e.g., the natural environment if it is naturally occurring). For example, a naturally occurring nucleic acid or polypeptide present in a living animal is not isolated, but the same nucleic acid or polypeptide, separated from some or all of the co-existing materials in the natural system, is isolated. Such nucleic acid could be part of a vector and/or such nucleic acid or polypeptide could be part of a composition (e.g., a cell lysate), and still be isolated in that such vector or composition is not part of the natural environment for the nucleic acid or polypeptide. "Isolated" can, in some embodiments, also describe an antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition that is outside of a human body. In certain embodiments, an isolated antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition is provided.

The term "gene" means the segment of DNA or RNA involved in producing a polypeptide chain; in certain contexts, it includes regions preceding and following the coding region (e.g., 5’ untranslated region (UTR) and 3’ UTR) as well as intervening sequences (introns) between individual coding segments (exons).

A "functional variant" refers to a polypeptide or polynucleotide that is structurally similar or substantially structurally similar to a parent or reference compound of this disclosure, but differs slightly in composition (e.g., one base, atom or functional group is different, added, or removed, or one or more amino acid or nucleotide is substituted), such that the polypeptide or encoded polypeptide is capable of performing at least one function of the parent polypeptide with at least 50% efficiency, preferably at least 55%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.9%, or 100% level of activity of the parent polypeptide. In other words, a functional variant of a polypeptide or encoded polypeptide of this disclosure has "similar binding," "similar affinity" or "similar activity" when the functional variant displays no more than a 50% reduction in performance in a selected assay as compared to the parent or reference polypeptide, such as an assay for measuring binding affinity (e.g., Biacore® or tetramer staining measuring an association (Ka) or a dissociation (KD) constant).

As used herein, a "functional portion" or "functional fragment" refers to a polypeptide or polynucleotide that comprises only a domain, portion or fragment of a parent or reference compound, and the polypeptide or encoded polypeptide retains at least 50% activity associated with the domain, portion or fragment of the parent or reference compound, preferably at least 55%, at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, at least 99.9%, or 100% level of activity of the parent polypeptide, or provides a biological benefit (e.g., effector function). A "functional portion" or "functional fragment" of a polypeptide or encoded polypeptide of this disclosure has "similar binding" or "similar activity" when the functional portion or fragment displays no more than a 50% reduction in performance in a selected assay as compared to the parent or reference polypeptide (preferably no more than 20% or 10%, or no more than a log difference as compared to the parent or reference with regard to affinity).

As used herein, the term "engineered," "recombinant," or "non-natural" refers to an organism, microorganism, cell, nucleic acid molecule, or vector that includes at least one genetic alteration or has been modified by introduction of an exogenous or heterologous nucleic acid molecule, wherein such alterations or modifications are introduced by genetic engineering (i.e., human intervention). Genetic alterations include, for example, modifications introducing expressible nucleic acid molecules encoding functional RNA, proteins, fusion proteins or enzymes, or other nucleic acid molecule additions, deletions, substitutions, or other functional disruption of a cell’s genetic material. Additional modifications include, for example, non-coding regulatory regions in which the modifications alter expression of a polynucleotide, gene, or operon.

As used herein, "heterologous" or "non-endogenous" or "exogenous" refers to any gene, protein, compound, nucleic acid molecule, or activity that is not native to a host cell or a subject, or any gene, protein, compound, nucleic acid molecule, or activity native to a host cell or a subject that has been altered. Heterologous, non-endogenous, or exogenous includes genes, proteins, compounds, or nucleic acid molecules that have been mutated or otherwise altered such that the structure, activity, or both is different as between the native and altered genes, proteins, compounds, or nucleic acid molecules. In certain embodiments, heterologous, non-endogenous, or exogenous genes, proteins, or nucleic acid molecules (e.g., receptors, ligands, etc.) may not be endogenous to a host cell or a subject, but instead nucleic acids encoding such genes, proteins, or nucleic acid molecules may have been added to a host cell by conjugation, transformation, transfection, electroporation, or the like, wherein the added nucleic acid molecule may integrate into a host cell genome or can exist as extra-chromosomal genetic material (e.g., as a plasmid or other self-replicating vector). The term "homologous" or "homolog" refers to a gene, protein, compound, nucleic acid molecule, or activity found in or derived from a host cell, species, or strain. For example, a heterologous or exogenous polynucleotide or gene encoding a polypeptide may be homologous to a native polynucleotide or gene and encode a homologous polypeptide or activity, but the polynucleotide or polypeptide may have an altered structure, sequence, expression level, or any combination thereof. A non-endogenous polynucleotide or gene, as well as the encoded polypeptide or activity, may be from the same species, a different species, or a combination thereof.

In certain embodiments, a nucleic acid molecule or portion thereof native to a host cell will be considered heterologous to the host cell if it has been altered or mutated, or a nucleic acid molecule native to a host cell may be considered heterologous if it has been altered with a heterologous expression control sequence or has been altered with an endogenous expression control sequence not normally associated with the nucleic acid molecule native to a host cell. In addition, the term "heterologous" can refer to a biological activity that is different, altered, or not endogenous to a host cell. As described herein, more than one heterologous nucleic acid molecule can be introduced into a host cell as separate nucleic acid molecules, as a plurality of individually controlled genes, as a polycistronic nucleic acid molecule, as a single nucleic acid molecule encoding a fusion protein, or any combination thereof. As used herein, the term "endogenous" or "native" refers to a polynucleotide, gene, protein, compound, molecule, or activity that is normally present in a host cell or a subject.

The term "expression", as used herein, refers to the process by which a polypeptide is produced based on the encoding sequence of a nucleic acid molecule, such as a gene. The process may include transcription, post-transcriptional control, post-transcriptional modification, translation, post-translational control, post- translational modification, or any combination thereof. An expressed nucleic acid molecule is typically operably linked to an expression control sequence (e.g., a promoter).

The term "operably linked" or “operatively linked” refers to the association of two or more nucleic acid molecules on a single nucleic acid fragment so that the function of one is affected by the other. For example, a promoter is operably linked with a coding sequence when it is capable of affecting the expression of that coding sequence (i.e., the coding sequence is under the transcriptional control of the promoter). "Unlinked" means that the associated genetic elements are not closely associated with one another and the function of one does not affect the other.

As described herein, more than one heterologous nucleic acid molecule can be introduced into a host cell as separate nucleic acid molecules, as a plurality of individually controlled genes, as a polycistronic nucleic acid molecule, as a single nucleic acid molecule encoding a protein (e.g., a heavy chain of an antibody), or any combination thereof. When two or more heterologous nucleic acid molecules are introduced into a host cell, it is understood that the two or more heterologous nucleic acid molecules can be introduced as a single nucleic acid molecule (e.g., on a single vector), on separate vectors, integrated into the host chromosome at a single site or multiple sites, or any combination thereof. The number of referenced heterologous nucleic acid molecules or protein activities refers to the number of encoding nucleic acid molecules or the number of protein activities, not the number of separate nucleic acid molecules introduced into a host cell. The term "construct" refers to any polynucleotide that contains a recombinant nucleic acid molecule (or, when the context clearly indicates, a fusion protein of the present disclosure). A (polynucleotide) construct may be present in a vector (e.g., a bacterial vector, a viral vector) or may be integrated into a genome. A "vector" is a nucleic acid molecule that is capable of transporting another nucleic acid molecule. Vectors may be, for example, plasmids, cosmids, viruses, a RNA vector or a linear or circular DNA or RNA molecule that may include chromosomal, non-chromosomal, semi-synthetic or synthetic nucleic acid molecules. Vectors of the present disclosure also include transposon systems (e.g., Sleeping Beauty, see, e.g., Geurts et al., Mol. Ther. 5:108, 2003: Mates et al., Nat. Genet. 41 :753, 2009). Other examples of transposon-based systems that can be used include, but are not limited to: piggybac (e.g., derived from lepidopteran cells and/or the Myotis lucifugus); mariner (e.g., derived from Drosophila); frog prince (e.g., derived from Rana pipiens); Tol2 (e.g., derived from medaka fish); and spinON. Exemplary vectors are those capable of autonomous replication (episomal vector), capable of delivering a polynucleotide to a cell genome (e.g., viral vector), or capable of expressing nucleic acid molecules to which they are linked (expression vectors).

As used herein, "expression vector" or "vector" refers to a DNA construct containing a nucleic acid molecule that is operably linked to a suitable control sequence capable of effecting the expression of the nucleic acid molecule in a suitable host. Such control sequences include a promoter to effect transcription, an optional operator sequence to control such transcription, a sequence encoding suitable mRNA ribosome binding sites, and sequences which control termination of transcription and translation. The vector may be a plasmid, a phage particle, a virus, or simply a potential genomic insert. Once transformed into a suitable host, the vector may replicate and function independently of the host genome, or may, in some instances, integrate into the genome itself or deliver the polynucleotide contained in the vector into the genome without the vector sequence. In the present specification, "plasmid," "expression plasmid," "virus," and "vector" are often used interchangeably. The term "introduced" in the context of inserting a nucleic acid molecule into a cell, means "transfection", "transformation," or "transduction" and includes reference to the incorporation of a nucleic acid molecule into a eukaryotic or prokaryotic cell wherein the nucleic acid molecule may be incorporated into the genome of a cell (e.g., chromosome, plasmid, plastid, or mitochondrial DNA), converted into an autonomous replicon, or transiently expressed (e.g., transfected mRNA).

In certain embodiments, polynucleotides of the present disclosure may be operatively linked to certain elements of a vector. For example, polynucleotide sequences that are needed to effect the expression and processing of coding sequences to which they are ligated may be operatively linked. Expression control sequences may include appropriate transcription initiation, termination, promoter, and enhancer sequences; efficient RNA processing signals such as splicing and polyadenylation signals; sequences that stabilize cytoplasmic mRNA; sequences that enhance translation efficiency (z.e., Kozak consensus sequences); sequences that enhance protein stability; and possibly sequences that enhance protein secretion. Expression control sequences may be operatively linked if they are contiguous with the gene of interest and expression control sequences that act in trans or at a distance to control the gene of interest.

In certain embodiments, the vector comprises a plasmid vector or a viral vector (e.g., a lentiviral vector or a y-retroviral vector). Viral vectors include retrovirus, adenovirus, parvovirus (e.g., adeno-associated viruses), coronavirus, negative strand RNA viruses such as ortho-myxovirus (e.g., influenza virus), rhabdovirus (e.g., rabies and vesicular stomatitis virus), paramyxovirus (e.g., measles and Sendai), positive strand RNA viruses such as picornavirus and alphavirus, and double-stranded DNA viruses including adenovirus, herpesvirus (e.g., Herpes Simplex virus types 1 and 2, Epstein-Barr virus, cytomegalovirus), and poxvirus (e.g., vaccinia, fowlpox, and canarypox). Other viruses include, for example, Norwalk virus, togavirus, flavivirus, reoviruses, papovavirus, hepadnavirus, and hepatitis virus. Examples of retroviruses include avian leukosis-sarcoma, mammalian C-type, B-type viruses, D type viruses, HTLV-BLV group, lentivirus, spumavirus (Coffin, J. M., Retroviridae: The viruses and their replication, In Fundamental Virology, Third Edition, B. N. Fields et al., Eds., Lippincott-Raven Publishers, Philadelphia, 1996).

"Retroviruses" are viruses having an RNA genome, which is reverse-transcribed into DNA using a reverse transcriptase enzyme, the reverse-transcribed DNA is then incorporated into the host cell genome. "Gammaretrovirus" refers to a genus of the retroviridae family. Examples of gammaretroviruses include mouse stem cell virus, murine leukemia virus, feline leukemia virus, feline sarcoma virus, and avian reticuloendotheliosis viruses.

"Lentiviral vectors" include HIV-based lentiviral vectors for gene delivery, which can be integrative or non-integrative, have relatively large packaging capacity, and can transduce a range of different cell types. Lentiviral vectors are usually generated following transient transfection of three (packaging, envelope, and transfer) or more plasmids into producer cells. Like HIV, lentiviral vectors enter the target cell through the interaction of viral surface glycoproteins with receptors on the cell surface. On entry, the viral RNA undergoes reverse transcription, which is mediated by the viral reverse transcriptase complex. The product of reverse transcription is a double-stranded linear viral DNA, which is the substrate for viral integration into the DNA of infected cells.

In certain embodiments, the viral vector can be a gammaretrovirus, e.g., Moloney murine leukemia virus (MLV)-derived vectors. In other embodiments, the viral vector can be a more complex retrovirus-derived vector, e.g., a lentivirus-derived vector. HIV-l-derived vectors belong to this category. Other examples include lentivirus vectors derived from HIV-2, FIV, equine infectious anemia virus, SIV, and Maedi-Visna virus (ovine lentivirus). Methods of using retroviral and lentiviral viral vectors and packaging cells for transducing mammalian host cells with viral particles containing transgenes are known in the art and have been previous described, for example, in: U.S. Patent 8,119,772; Walchli et al., PLoS One 6.321939, 2011; Zhao et al., J. Immunol. 174 AM5, 2005; Engels et al., Hum. Gene Ther. 77: 1155, 2003; Frecha et al., Mol. Ther. 18.Y1 , 2010; and Verhoeyen et al ., Methods Mol. Biol. 506.91 , 2009. Retroviral and lentiviral vector constructs and expression systems are also commercially available. Other viral vectors also can be used for polynucleotide delivery including DNA viral vectors, including, for example adenovirus-based vectors and adeno-associated virus (AAV)-based vectors; vectors derived from herpes simplex viruses (HSVs), including amplicon vectors, replication-defective HSV and attenuated HSV (Krisky et al., Gene Ther. 5: 1517, 1998).

Other vectors that can be used with the compositions and methods of this disclosure include those derived from baculoviruses and a-viruses. (Jolly, D J. 1999. Emerging Viral Vectors, pp 209-40 in Friedmann T. ed. The Development of Human Gene Therapy. New York: Cold Spring Harbor Lab), or plasmid vectors (such as sleeping beauty or other transposon vectors).

When a viral vector genome comprises a plurality of polynucleotides to be expressed in a host cell as separate transcripts, the viral vector may also comprise additional sequences between the two (or more) transcripts allowing for bicistronic or multi ci str onic expression. Examples of such sequences used in viral vectors include internal ribosome entry sites (IRES), furin cleavage sites, viral 2A peptide, or any combination thereof.

Plasmid vectors, including DNA-based antibody or antigen-binding fragmentencoding plasmid vectors for direct administration to a subject, are described further herein.

As used herein, the term "host" refers to a cell or microorganism targeted for genetic modification with a heterologous nucleic acid molecule to produce a polypeptide of interest (e.g., an antibody of the present disclosure).

A host cell may include any individual cell or cell culture which may receive a vector or the incorporation of nucleic acids or express proteins. The term also encompasses progeny of the host cell, whether genetically or phenotypically the same or different. Suitable host cells may depend on the vector and may include mammalian cells, animal cells, human cells, simian cells, insect cells, yeast cells, and bacterial cells. These cells may be induced to incorporate the vector or other material by use of a viral vector, transformation via calcium phosphate precipitation, DEAE-dextran, electroporation, microinjection, or other methods. See, for example, Sambrook et al., Molecular Cloning: A Laboratory Manual 2d ed. (Cold Spring Harbor Laboratory, 1989).

In the context of a parvovirus infection, a "host" refers to a cell or a subject infected with a parvovirus. In certain embodiments, a host subject is infected with parvovirus B 19 and/or has a chronic parvovirus infection.

"Antigen" or "Ag", as used herein, refers to an immunogenic molecule that provokes an immune response. This immune response may involve antibody production, activation of specific immunologically-competent cells, activation of complement, antibody dependent cytotoxicicity, or any combination thereof. An antigen (immunogenic molecule) may be, for example, a peptide, glycopeptide, polypeptide, glycopolypeptide, polynucleotide, polysaccharide, lipid, or the like. It is readily apparent that an antigen can be synthesized, produced recombinantly, or derived from a biological sample. Exemplary biological samples that can contain one or more antigens include tissue samples, stool samples, cells, biological fluids, or combinations thereof. Antigens can be produced by cells that have been modified or genetically engineered to express an antigen. Antigens can also be present in a parvovirus antigen, such as present in a virion, or expressed or presented on the surface of a cell infected by the parvovirus.

The term "epitope" or "antigenic epitope" includes any molecule, structure, amino acid sequence, or protein determinant that is recognized and specifically bound by a cognate binding molecule, such as an immunoglobulin, or other binding molecule, domain, or protein. Epitopic determinants generally contain chemically active surface groupings of molecules, such as amino acids or sugar side chains, and can have specific three-dimensional structural characteristics, as well as specific charge characteristics. Where an antigen is or comprises a peptide or protein, the epitope can be comprised of consecutive amino acids (e.g., a linear epitope), or can be comprised of amino acids from different parts or regions of the protein that are brought into proximity by protein folding (e.g., a discontinuous or conformational epitope), or non-contiguous amino acids that are in close proximity irrespective of protein folding. Antibodies, Antigen-Binding Fragments, and Compositions

In one aspect, the present disclosure provides an anti-parvovirus antibody, or an antigen-binding fragment thereof. In some embodiments, the parvovirus comprises a parvovirus Bl 9. In some embodiments, the parvovirus is a parvovirus Bl 9. In some embodiments, an antibody or antigen-binding fragment binds an epitope in B19 uVPl. In other embodiments, an antibody or antigen-binding fragment binds an epitope in B19 VP2. Briefly, the parvovirus human pathogen B 19 comprises an icosahedral nonenveloped capsid comprising VP1 (reported MW of 82 kDa) and VP2 (reported MW of 60 kDa) proteins. VP1 comprises the entire sequence of VP2 coat protein, as well as a unique N-terminal region (uVPl or VPlu). See, e.g., Bilkova et al. Viruses 6(7):2899- 2937 (2014). Unless the context provides otherwise, a “VP 1 -specific” antibody or antigen-binding fragment binds to an epitope in uVPl.

In certain embodiments, an antibody or antigen-binding fragment of the present disclosure associates with or unites with a parvovirus (e.g., a B19, optionally binding to a uVPl or a VP2) while not significantly associating or uniting with any other molecules or components in a sample.

In certain embodiments, an antibody or antigen-binding fragment of the present disclosure specifically binds to a uVPl or a VP2. As used herein, "specifically binds" refers to an association or union of an antibody or antigen-binding fragment to an antigen with an affinity or K_a (i.e., an equilibrium association constant of a particular binding interaction with units of 1/M) equal to or greater than 10⁵ M'¹ (which equals the ratio of the on-rate [K_on] to the off rate [K_Off] for this association reaction), while not significantly associating or uniting with any other molecules or components in a sample. Alternatively, affinity may be defined as an equilibrium dissociation constant (Ka) of a particular binding interaction with units of M e.g., 10'⁵ M to 10'¹³ M). Antibodies may be classified as "high-affinity" antibodies or as "low-affinity" antibodies. "High-affinity" antibodies refer to those antibodies having a K_a of at least 10⁷M^-1, at least 10⁸ M'¹, at least 10⁹ M'¹, at least IO¹⁰ M'¹, at least 10¹¹ M'¹, at least 10¹² M'¹, or at least 10¹³ M'¹. "Low-affinity" antibodies refer to those antibodies having a K_a of up to 10⁷M^-1, up to 10⁶ M'¹, up to 10⁵ M'¹. Alternatively, affinity may be defined as an equilibrium dissociation constant (Kd) of a particular binding interaction with units of M (e.g., 10'⁵ M to 10'¹³ M).

A variety of assays are known for identifying antibodies of the present disclosure that bind a particular target, as well as determining binding domain or binding protein affinities, such as Western blot, ELISA (e.g., direct, indirect, or sandwich), analytical ultracentrifugation, spectroscopy, biolayer interferometry, and surface plasmon resonance (Biacore®) analysis (see, e.g., Scatchard et al., Ann. N.Y. Acad. Sci. 57:660, 1949; Wilson, Science 295:2103, 2002; Wolff et al., Cancer Res. 53:2560, 1993; and U.S. Patent Nos. 5,283,173, 5,468,614, or the equivalent). Assays for assessing affinity or apparent affinity or relative affinity are also known.

In certain examples, binding can be determined by recombinantly expressing a uVPl or a VP2 in a host cell (e.g., by transfection) and immunostaining the (e.g, fixed, or fixed and permeabilized) host cell with antibody and analyzing binding by flow cytometery (e.g., using a ZE5 Cell Analyzer (BioRad®) and FlowJo software (TreeStar). In some embodiments, positive binding can be defined by differential staining by antibody of uVPl - or VP2-expressing cells versus control (e.g., mock) cells.

In some embodiments an antibody or antigen-binding fragment of the present disclosure binds to a uVPl or a VP2, as measured using biolayer interferometry, or by surface plasmon resonance, or by ELISA.

Certain characteristics of presently disclosed antibodies or antigen-binding fragments may be described using IC50 or EC50 values. In certain embodiments, the IC50 is the concentration of a composition (e.g., antibody) that results in half-maximal inhibition of the indicated biological or biochemical function, activity, or response. In certain embodiments, the EC50 is the concentration of a composition that provides the half-maximal response in the assay. In some embodiments, e.g., for describing the ability of a presently disclosed antibody or antigen-binding fragment to neutralize infection by a parvovirus (e.g. B19), IC50 and EC50 are used interchangeably.

In certain embodiments, an antibody of the present disclosure is capable of neutralizing infection by a parvovirus. As used herein, a "neutralizing antibody" is one that can neutralize, i.e., prevent, inhibit, reduce, impede, or interfere with, the ability of a pathogen to initiate and/or perpetuate an infection in a host. The terms "neutralizing antibody" and "an antibody that neutralizes" or "antibodies that neutralize" are used interchangeably herein. In any of the presently disclosed embodiments, the antibody or antigen-binding fragment can be capable of preventing and/or neutralizing a parvovirus infection in an in vitro model of infection and/or in an in vivo animal model of infection and/or in a human.

In certain embodiments, the antibody, or antigen-binding fragment thereof, is human, humanized, or chimeric.

Terms understood by those in the art of antibody technology are each given the meaning acquired in the art, unless expressly defined differently herein. For example, the term "antibody" refers to an intact antibody comprising at least two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds, as well as any antigen-binding portion or fragment of an intact antibody that has or retains the ability to bind to the antigen target molecule recognized by the intact antibody, such as an scFv, Fab, or Fab'2 fragment. Thus, the term "antibody" herein is used in the broadest sense and includes polyclonal and monoclonal antibodies, including intact antibodies and functional (antigen-binding) antibody fragments thereof, including fragment antigen binding (Fab) fragments, F(ab')2 fragments, Fab' fragments, Fv fragments, recombinant IgG (rlgG) fragments, single chain antibody fragments, including single chain variable fragments (scFv), and single domain antibodies (e.g., sdAb, sdFv, nanobody) fragments. The term encompasses genetically engineered and/or otherwise modified forms of immunoglobulins, such as intrabodies, peptibodies, chimeric antibodies, fully human antibodies, humanized antibodies, and heteroconjugate antibodies, multi specific, e.g., bi specific antibodies, diabodies, triabodies, tetrabodies, tandem di-scFv, and tandem tri-scFv. Unless otherwise stated, the term "antibody" should be understood to encompass functional antibody fragments thereof. The term also encompasses intact or full-length antibodies, including antibodies of any class or sub-class, including IgG and sub-classes thereof (IgGl, IgG2, IgG3, IgG4), IgM, IgE, IgA, and IgD. The terms "VL" or "VL" and " VH" or "VH" refer to the variable binding region from an antibody light chain and an antibody heavy chain, respectively. In certain embodiments, a VL is a kappa (K) class (also "VK" herein). In certain embodiments, a VL is a lambda (X) class. The variable binding regions comprise discrete, well-defined sub-regions known as "complementarity determining regions" (CDRs) and "framework regions" (FRs). The terms "complementarity determining region," and "CDR," are synonymous with "hypervariable region" or "HVR," and refer to sequences of amino acids within antibody variable regions, which, in general, together confer the antigen specificity and/or binding affinity of the antibody, wherein consecutive CDRs (i.e., CDR1 and CDR2, CDR2 and CDR3) are separated from one another in primary structure by a framework region. There are three CDRs in each variable region (HCDR1, HCDR2, HCDR3; LCDR1, LCDR2, LCDR3; also referred to as CDRHs and CDRLs, respectively). In certain embodiments, an antibody VH comprises four FRs and three CDRs as follows: FR1-HCDR1-FR2-HCDR2-FR3-HCDR3-FR4; and an antibody VL comprises four FRs and three CDRs as follows: FR1-LCDR1-FR2- LCDR2-FR3-LCDR3-FR4. In general, the VH and the VL together form the antigenbinding site through their respective CDRs. In certain embodiments, one or more CDRs do not contact antigen and/or do not contribute energetically to antigen binding.

As used herein, a "variant" of a CDR refers to a functional variant of a CDR sequence having up to 1-3 amino acid substitutions (e.g., conservative or nonconservative substitutions), deletions, or combinations thereof. A functional variant of a CDR substantially retains the conformation and optionally the binding function of a native or parent CDR.

Numbering of CDR and framework regions may be according to any known method or scheme, such as the Kabat, Chothia, EU, IMGT, Contact, North, Martin, AbM, and AHo numbering schemes see, e.g., Kabat et al., "Sequences of Proteins of Immunological Interest, US Dept. Health and Human Services, Public Health Service National Institutes of Health, 1991, 5^th ed.; Chothia and Lesk, J. Mol. Biol. 796:901-917 (1987)); Lefranc et al., Dev. Comp. Immunol. 27:55, 2003; Honegger and Pliickthun, J. Mol. Bio. 309:65'1-6'10 (2001); North et al. J Mol Biol. (2011) 406:228-56; doi: 10.1016/j.jmb.2010.10.030; Abhinandan and Martin, Mol

Immunol. (2008) 45:3832-9. 10.1016/j.molimm.2008.05.022). The antibody and CDR numbering systems of these references are incorporated herein by reference. Equivalent residue positions can be annotated and for different molecules to be compared using Antigen receptor Numbering And Receptor Classification (ANARCI) software tool (2016, Bioinformatics 15:298-300). Accordingly, identification of CDRs of an exemplary variable domain (VH or VL) sequence as provided herein according to one numbering scheme is not exclusive of an antibody comprising CDRs of the same variable domain as determined using a different numbering scheme. In certain embodiments, an antibody or antigen-binding fragment is provided that comprises one or more CDRs of a VH sequence according to any one of SEQ ID NOs.:7, 17, and 27, and/or of a VL sequence according to any one of SEQ ID NOs.: 12, 22, and 32, in accordance with any known CDR numbering method, including the Kabat, Chothia, North, EU, IMGT, Martin (Enhanced Chothia), Contact, AbM, and AHo numbering methods, or in accordance with a combination of two or more of these methods (e.g., including those residues falling within a CDR as defined by either or all of the numbering methods). In certain embodiments, CDRs are according to the IMGT numbering method (optionally using junction definitions for CDR3 amino acid sequences). In certain embodiments, CDRs are according to the antibody numbering method developed by the Chemical Computing Group (CCG); e.g., using Molecular Operating Environment (MOE) software (chemcomp.com). In some embodiments, CDRs are in accordance with the IMGT numbering method.

In some embodiments, an antibody or antigen-binding fragment comprises a CDRH1, a CDRH2, a CDRH3, a CDRL1, a CDRL2, and/or a CDRL3 of exemplary antibody PAB18, PAB5, or PAA19, as set forth in Table A. In some embodiments, an antibody or antigen-binding fragment comprises a VH and/or a VL of exemplary antibody PAB18, PAB5, or PAA19, as set forth in Table A. Tab e A. Amino Acid SEQ ID NOs. of Certain Antibody Sequences

Variable domain amino acid sequences, with IMGT CDRs shown in bold font, are also shown for antibodies PAB18, PAB5, and PAA19 in Figures 8A-8C, respectively.

Table B shows certain variable domain germline alleles corresponding to PAB18, PAB5, and PAA19, and percent identity of the antibody VH domain to the VH germline sequence.

In some embodiments, an antibody or antigen-binding fragment comprises a VH comprising an amino acid sequence having at least 80%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence encoded by VH1-69. In certain embodiments, the antibody or antigen-binding fragment comprises a VL of kappa class.

In some embodiments, an antibody or antigen-binding fragment comprises a VH comprising an amino acid sequence having at least 80%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence encoded by VH3-21. In certain embodiments, the antibody or antigen-binding fragment comprises a VL of kappa class. In some embodiments, an antibody or antigen-binding fragment comprises a VH comprising an amino acid sequence having at least 80%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence encoded by VH4-39. In certain embodiments, the antibody or antigen-binding fragment comprises a VL of kappa class.

In some embodiments, an antibody or antigen-binding fragment comprises the CDRH3 amino acid sequence of the VH amino acid sequence set forth in SEQ ID NO.:7 and the CDRL3 amino acid sequence of the VL amino acid sequence set forth in SEQ ID NO. : 12, wherein the CDRH3 and the CDRL3 are according to IMGT, or are according to Kabat, or are according to Chothia, or are according to Martin, or are according to AHo, or are according to North, or are according to AbM, or are according to CCG, or are according to Contact, or are according to EU, or are according to a combination of two or more of the foregoing.

In some embodiments, an antibody or antigen-binding fragment comprises the CDRH3 amino acid sequence of the VH amino acid sequence set forth in SEQ ID NO. : 17 and the CDRL3 amino acid sequence of the VL amino acid sequence set forth in SEQ ID NO.: 22, wherein the CDRH3 and CDRL3 are according to IMGT, or are according to Kabat, or are according to Chothia, or are according to Martin, or are according to AHo, or are according to North, or are according to AbM, or are according to CCG, or are according to Contact, or are according to EU, or are according to a combination of two or more of the foregoing.

In some embodiments, an antibody or antigen-binding fragment comprises the CDRH3 amino acid sequence of the VH amino acid sequence set forth in SEQ ID NO.:27 and the CDRL3 amino acid sequence of the VL amino acid sequence set forth in SEQ ID NO.: 32, wherein the CDRH3 and CDRL3 are according to IMGT, or are according to Kabat, or are according to Chothia, or are according to Martin, or are according to AHo, or are according to North, or are according to AbM, or are according to CCG, or are according to Contact, or are according to EU, or are according to a combination of two or more of the foregoing. In some embodiments, an antibody or antigen-binding fragment comprises the CDRH1, CDRH2, and CDRH3 amino acid sequences of the VH amino acid sequence set forth in SEQ ID NO.:7, and the CDRL1, CDRL2, and CDRL3 amino acid sequences of the VL amino acid sequences set forth in SEQ ID NO.: 12, wherein the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 are according to IMGT, or are according to Kabat, or are according to Chothia, or are according to Martin, or are according to AHo, or are according to North, or are according to AbM, or are according to CCG, or are according to Contact, or are according to EU, or are according to a combination of two or more of the foregoing.

In some embodiments, an antibody or antigen-binding fragment comprises the CDRH1, CDRH2, and CDRH3 amino acid sequences of the VH amino acid sequence set forth in SEQ ID NO.: 17, and the CDRL1, CDRL2, and CDRL3 amino acid sequences of the VL amino acid sequences set forth in SEQ ID NO.:22, wherein the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 are according to IMGT, or are according to Kabat, or are according to Chothia, or are according to Martin, or are according to AHo, or are according to North, or are according to AbM, or are according to CCG, or are according to Contact, or are according to EU, or are according to a combination of two or more of the foregoing.

In some embodiments, an antibody or antigen-binding fragment comprises the CDRH1, CDRH2, and CDRH3 amino acid sequences of the VH amino acid sequence set forth in SEQ ID NO.:27, and the CDRL1, CDRL2, and CDRL3 amino acid sequences of the VL amino acid sequences set forth in SEQ ID NO.:32, wherein the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 are according to IMGT, or are according to Kabat, or are according to Chothia, or are according to Martin, or are according to AHo, or are according to North, or are according to AbM, or are according to CCG, or are according to Contact, or are according to EU, or are according to a combination of two or more of the foregoing.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)Hl, the CDRH2, and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment of the present disclosure binds to an epitope in B19 uVPl. In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment binds to a peptide having the amino acid sequence TGTDLE (SEQ ID NO.:4). In some embodiments, an antiparvovirus antibody or antigen-binding fragment binds to a peptide having the amino acid sequence X1X2TDX3EX4 (SEQ ID NO.: 5), wherein: Xi is present or absent, and, if present, is any amino acid; X2 is G or F, and is preferably G; X3 is L or K, and is preferably K; and X4 is present or absent, and, if present, is any amino acid except P.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and/or (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, or AHo numbering system, or in accordance with any combination thereof.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)Hl, the CDRH2, and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, or AHo numbering system, or in accordance with any combination thereof. In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.:20, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and (ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.:25, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO. : 18, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.: 19, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and (ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.:23, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.:24, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

In particular embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.: 18-20 and 23-25, respectively.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 17; and/or (ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:22. In some embodiments, amino acid sequence variation relative to SEQ ID NO.: 17 or SEQ ID NO.:22 is limited to variation relative to one or more framework regions (FRs) of SEQ ID NO : 17 or SEQ ID NO.:22, respectively.

Framework regions can be identified according to a numbering scheme (e.g., IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo, or a combination of two or more of these). The CDRs may be identified within a variable domain or within a heavy or light chain according to a numbering scheme or a combination of numbering schemes, and, preferably, the FRs may be identified using the same numbering scheme or combination of numbering schemes.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises a VH comprising a FR1, a FR2, a FR3, and/or a FR4 (or a variant of the FR1, FR2, FR3, and/or FR4 comprising one, two, three, four, or five amino acid substitutions, insertions, and/or deletions) of the VH amino acid sequence set forth in SEQ ID NO. : 17, and a VL comprising a a FR1, a FR2, a FR3, and/or a FR4 (or a variant of the FR1, FR2, FR3, and/or FR4 comprising one, two, three, four, or five amino acid substitutions, insertions, and/or deletions) of the VL amino acid sequence set forth in SEQ ID NO.:22. In some embodiments, the FRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence set forth in SEQ ID NO.: 17; and (ii) a light chain variable domain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence set forth in SEQ ID NO.:22.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising the amino acid sequence set forth in SEQ ID NO.: 17; and (ii) a light chain variable domain (VL) comprising the amino acid sequence set forth in SEQ ID NO.:22.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) consisting essentially of the amino acid sequence set forth in SEQ ID NO.: 17; and (ii) a light chain variable domain (VL) consisting essentially of the amino acid sequence set forth in SEQ ID NO.:22.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) consisting of the amino acid sequence set forth in SEQ ID NO.: 17; and (ii) a light chain variable domain (VL) consisting of the amino acid sequence set forth in SEQ ID NO.:22.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment binds to an epitope in B19 VP2.

In certain embodiments, an antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:7; and/or (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof. In certain further embodiments, an antiparvovirus antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region CDR)H1, the CDRH2, the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:7; and in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

In certain embodiments, an antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID N0.:7; and/or (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.: 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

In further embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region CDR)H1, the CDRH2, the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:7; and in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO. : 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.: 10, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and (ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.: 15, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.:8, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.:9, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and (ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.: 13, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO. : 14, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

In particular embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.:8-10 and 13-15, respectively.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:7; and/or (ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 12.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises a VH comprising a FR1, a FR2, a FR3, and/or a FR4 (or a variant of the FR1, FR2, FR3, and/or FR4 comprising one, two, three, four, or five amino acid substitutions, insertions, and/or deletions) of the VH amino acid sequence set forth in SEQ ID NO. :7, and a VL comprising a a FR1, a FR2, a FR3, and/or a FR4 (or a variant of the FR1, FR2, FR3, and/or FR4 comprising one, two, three, four, or five amino acid substitutions, insertions, and/or deletions) of the VL amino acid sequence set forth in SEQ ID NO. : 12. In some embodiments, the FRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence set forth in SEQ ID NO.:7; and (ii) a light chain variable domain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence set forth in SEQ ID NO. : 12. In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising the amino acid sequence set forth in SEQ ID NO.:7; and (ii) a light chain variable domain (VL) comprising the amino acid sequence set forth in SEQ ID NO. : 12.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) consisting essentially of the amino acid sequence set forth in SEQ ID NO.:7; and (ii) a light chain variable domain (VL) consisting essentially of the amino acid sequence set forth in SEQ ID NO.: 12.

In other embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and/or (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, or AHo numbering system, or in accordance with any combination thereof.

In other embodiments, an anti-parvovirus antibody or antigen-binding fragment of comprises: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and/or (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

In further embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and (ii) in a/the light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

In further embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and (ii) in a/the light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.:30, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; (ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.:35, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions. In some embodiments, an anti-parvovirus antibody or antigenbinding fragment comprises: (i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.:28, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.:29, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and (ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.:33, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.:34, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions. In particular embodiments, an anti-parvovirus antibody or antigen-binding fragment thereof comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.:28-30 and 33-35, respectively.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment thereof comprises: (i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:27; and/or (ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:32.

In certain embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises a VH comprising a FR1, a FR2, a FR3, and/or a FR4 (or a variant of the FR1, FR2, FR3, and/or FR4 comprising one, two, three, four, or five amino acid substitutions, insertions, and/or deletions) of the VH amino acid sequence set forth in SEQ ID NO. :27, and a VL comprising a a FR1, a FR2, a FR3, and/or a FR4 (or a variant of the FR1, FR2, FR3, and/or FR4 comprising one, two, three, four, or five amino acid substitutions, insertions, and/or deletions) of the VL amino acid sequence set forth in SEQ ID NO.:32. In some embodiments, the FRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

In further embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising, consisting essentially of, or consisting of the amino acid sequence set forth in SEQ ID NO.:27; and (ii) a light chain variable domain (VL) comprising, consisting essentially of, or consisting of the amino acid sequence set forth in SEQ ID NO.:32. In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) comprising the amino acid sequence set forth in SEQ ID NO.:27; and (ii) a light chain variable domain (VL) comprising the amino acid sequence set forth in SEQ ID NO.:32.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) consisting essentially of the amino acid sequence set forth in SEQ ID NO.:27; and (ii) a light chain variable domain (VL) consisting essentially of the amino acid sequence set forth in SEQ ID NO.:32.

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment comprises: (i) a heavy chain variable domain (VH) consisting of the amino acid sequence set forth in SEQ ID NO.:27; and (ii) a light chain variable domain (VL) consisting of the amino acid sequence set forth in SEQ ID NO.:32.

The term "CL" refers to an "immunoglobulin light chain constant region" or a "light chain constant region," z.e., a constant region from an antibody light chain. The term "CH" refers to an "immunoglobulin heavy chain constant region" or a "heavy chain constant region," which is further divisible, depending on the antibody isotype, into CHI, CH2, and CH3 (IgA, IgD, IgG), or CHI, CH2, CH3, and CH4 domains (IgE, IgM). The Fc region of an antibody heavy chain is described further herein. In any of the presently disclosed embodiments, an antibody or antigen-binding fragment of the present disclosure comprises any one or more of CL, a CHI, a CH2, and a CH3. In any of the presently disclosed embodiments, an antibody or antigen-binding fragment of the present disclosure may comprise any one or more of CL, a CHI, a CH2, and a CH3. In certain embodiments, a CL comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the amino acid sequence of SEQ ID NO.:36. In certain embodiments, a CL comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to a human lambda light chain constant domain. In certain embodiments, a CH1-CH3 comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the amino acid sequence of any one of SEQ ID NOs.:38-42.

In certain embodiments, a Fc polypeptide comprises an amino acid sequence having at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identity to the amino acid sequence of SEQ ID NO.:37.

It will be understood that, for example, production in a mammalian cell line can remove one or more C-terminal lysine of an antibody heavy chain (see, e.g., Liu et al. mAbs 6(5): 1145-1154 (2014)). Accordingly, an antibody or antigen-binding fragment of the present disclosure can comprise a heavy chain, a CH1-CH3, a CH3, or an Fc polypeptide wherein a C-terminal lysine residue is present or is absent; in other words, encompassed are embodiments where the C-terminal residue of a heavy chain, a CH1- CH3, or an Fc polypeptide is not a lysine, and embodiments where a lysine is the C- terminal residue. In certain embodiments, a composition comprises a plurality of an antibody and/or an antigen-binding fragment of the present disclosure, wherein one or more antibody or antigen-binding fragment does not comprise a lysine residue at the C- terminal end of the heavy chain, CH1-CH3, or Fc polypeptide, and wherein one or more antibody or antigen-binding fragment comprises a lysine residue at the C-terminal end of the heavy chain, CH1-CH3, or Fc polypeptide.

AFc, Fc fragment or portion, or antibody, may be of any allotype or combination of allotypes. “Allotype” refers to the allelic variation found among the IgG subclasses. For example, an allotype may comprise Glml (or Glm(a)), Glm2 (or Glm(x)), Glm3 (or Glm(f)), Glml7 (or Gm(z))m), Glm27, and/or Glm28 (Glm27 and Glm28 have been described as “alloallotypes”).

The Glm3 and Glml7 allotypes are located at the same position in the CHI domain (position 214 according to EU numbering). Glm3 comprises R214 (EU), while Glml7 comprises K214 (EU). The Glml allotype is located in the CH3 domain (at positions 356 and 358 (EU)) and refers to the replacements E356D and M358L. The Glm2 allotype refers to a replacement of the alanine in position 431 (EU) by a glycine. Glm allotypes, alloallotypes, and features thereof are known in the art and described at, for example, www.imgt.org/IMGTrepertoire/Proteins/allotypes/human/IGH/IGHC/Glm_allotypes.ht ml and Lefranc, M.-P. and Lefranc, G. Human Gm, Km and Am allotypes and their molecular characterization: a remarkable demonstration of polymorphism In: B. Tait, E Christiansen (Eds.), Immunogenetics, chap. 34, Humana Press, Springer, New York, USA. Methods Mol. Biol. 2012; 882, 635-680. PMID: 22665258, LIGM: 406, the contents and allotypes and allotype information of which are incorporated herein by reference.

The Glml allotype may be combined, for example, with the Glm3, Glm 17, Glm27, Glm2, and/or Glm28 allotype. In some embodiments, an allotype is Glm3 with no Glml (Glm3,-1). In some embodiments, an allotype is Glml7,l allotype. In some embodiments, an allotype is Glm3,l. In some embodiments, an allotype is Glml7 with no Glml (Glml7,-1). Optionally, these allotypes may be combined (or not combined) with the Glm2, Glm27 or Glm28 allotype. For example, an allotype may be Glml7,l,2.

In some embodiments, a polypeptide, CH2, Fc, Fc fragment or portion, or antibody of the present disclosure comprises a Glm3 allotype or a Glm3,l allotype. In some embodiments, a polypeptide, CH2, Fc, Fc fragment or portion, or antibody of the present disclosure comprises a Glm3 allotype and comprises M428L and N434S or M428L and N434A mutations or any other mutation(s) that enhance binding to a human FcRn, such as those described herein. In some embodiments, a polypeptide, CH2, Fc, Fc fragment or portion, or antibody of the present disclosure comprises a Glm3,l allotype and comprises M428L and N434S or M428L and N434A mutations or any other mutation(s) that enhance binding to a human FcRn, such as those described herein. In some embodiments, a polypeptide, CH2, Fc, Fc fragment or portion, or antibody of the present disclosure comprises a Glml7, 1 allotype. In some embodiments, a polypeptide, CH2, Fc, Fc fragment or portion, or antibody of the present disclosure comprises a Glml7, 1 allotype and comprises M428L and N434S or M428L and N434A mutations or any other mutation(s) that enhance binding to a human FcRn, as described further herein.

A "Fab" (fragment antigen binding) is the part of an antibody that binds to antigens and includes the variable region and CHI of the heavy chain linked to the light chain via an inter-chain disulfide bond. Each Fab fragment is monovalent with respect to antigen binding, z.e., it has a single antigen-binding site. Pepsin treatment of an antibody yields a single large F(ab')2 fragment that roughly corresponds to two disulfide linked Fab fragments having divalent antigen-binding activity and is still capable of cross-linking antigen. Both the Fab and F(ab’)2 are examples of "antigenbinding fragments." Fab' fragments differ from Fab fragments by having additional few residues at the carboxy terminus of the CHI domain including one or more cysteines from the antibody hinge region. Fab'-SH is the designation herein for Fab' in which the cysteine residue(s) of the constant domains bear a free thiol group. F(ab')2 antibody fragments originally were produced as pairs of Fab' fragments that have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.

Fab fragments may be joined, e.g., by a peptide linker, to form a single chain Fab, also referred to herein as "scFab." In these embodiments, an inter-chain disulfide bond that is present in a native Fab may not be present, and the linker serves in full or in part to link or connect the Fab fragments in a single polypeptide chain. A heavy chain- derived Fab fragment (e.g., comprising, consisting of, or consisting essentially of VH + CHI, or "Fd") and a light chain-derived Fab fragment (e.g., comprising, consisting of, or consisting essentially of VL + CL) may be linked in any arrangement to form a scFab. For example, a scFab may be arranged, in N-terminal to C-terminal direction, according to (heavy chain Fab fragment - linker - light chain Fab fragment) or (light chain Fab fragment - linker - heavy chain Fab fragment). Peptide linkers and exemplary linker sequences for use in scFabs are discussed in further detail herein.

"Fv" is a small antibody fragment that contains a complete antigen-recognition and antigen-binding site. This fragment generally consists of a dimer of one heavy- and one light-chain variable region domain in tight, non-covalent association. However, even a single variable domain (or half of an Fv comprising only three CDRs specific for an antigen) has the ability to recognize and bind antigen, although typically at a lower affinity than the entire binding site.

"Single-chain Fv" also abbreviated as "sFv" or "scFv", are antibody fragments that comprise the VH and VL antibody domains connected into a single polypeptide chain. In some embodiments, the scFv polypeptide comprises a polypeptide linker disposed between and linking the VH and VL domains that enables the scFv to retain or form the desired structure for antigen binding. Such a peptide linker can be incorporated into a fusion polypeptide using standard techniques well known in the art. For a review of scFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds., Springer- Verlag, New York, pp. 269-315 (1994); Borrebaeck 1995, infra. In certain embodiments, the antibody or antigen-binding fragment comprises a scFv comprising a VH domain, a VL domain, and a peptide linker linking the VH domain to the VL domain. In particular embodiments, a scFv comprises a VH domain linked to a VL domain by a peptide linker, which can be in a VH-linker- VL orientation or in a VL-linker-VH orientation. Any scFv of the present disclosure may be engineered so that the C-terminal end of the VL domain is linked by a short peptide sequence to the N-terminal end of the VH domain, or vice versa (i.e., (N)VL(C)-linker-(N)VH(C) or (N)VH(C)-linker-(N)VL(C). Alternatively, in some embodiments, a linker may be linked to an N-terminal portion or end of the VH domain, the VL domain, or both.

Peptide linker sequences may be chosen, for example, based on: (1) their ability to adopt a flexible extended conformation; (2) their inability or lack of ability to adopt a secondary structure that could interact with functional epitopes on the first and second polypeptides and/or on a target molecule; and/or (3) the lack or relative lack of hydrophobic or charged residues that might react with the polypeptides and/or target molecule. Other considerations regarding linker design (e.g., length) can include the conformation or range of conformations in which the VH and VL can form a functional antigen-binding site. In certain embodiments, peptide linker sequences contain, for example, Gly, Asn and Ser residues. Other near neutral amino acids, such as Thr and Ala, may also be included in a linker sequence. Other amino acid sequences which may be usefully employed as linker include those disclosed in Maratea et al., Gene 40:39 46 (1985); Murphy et al., Proc. Natl. Acad. Sci. USA 83:8258 8262 (1986); U.S. Pat. No. 4,935,233, and U.S. Pat. No. 4,751,180. Other illustrative and non-limiting examples of linkers may include, for example, Glu-Gly-Lys-Ser-Ser-Gly-Ser-Gly-Ser-Glu-Ser-Lys- Val-Asp (Chaudhary et al., Proc. Natl. Acad. Sci. USA 87:1066-1070 (1990)) and Lys- Glu-Ser-Gly-Ser-Val-Ser-Ser-Glu-Gln-Leu-Ala-Gln-Phe-Arg-Ser-Leu-Asp (Bird et al., Science 242:423-426 (1988)) and the pentamer Gly-Gly-Gly-Gly-Ser when present in a single iteration or repeated 1 to 5 or more times, or more. Any suitable linker may be used, and in general can be about 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 15 23, 24, 25, 26, 27, 28, 29, 30, 40, 50, 60, 70, 80, 90, 100 amino acids in length, or less than about 200 amino acids in length, and will preferably comprise a flexible structure (can provide flexibility and room for conformational movement between two regions, domains, motifs, fragments, or modules connected by the linker), and will preferably be biologically inert and/or have a low risk of immunogenicity in a human. ScFvs can be constructed using any combination of the VH and VL sequences or any combination of the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 sequences disclosed herein. In some embodiments, linker sequences are not required; for example, when the first and second polypeptides have non-essential N-terminal amino acid regions that can be used to separate the functional domains and prevent steric interference.

During antibody development, DNA in the germline variable (V), joining (J), and diversity (D) gene loci may be rearranged and insertions and/or deletions of nucleotides in the coding sequence may occur. Somatic mutations may be encoded by the resultant sequence, and can be identified by reference to a corresponding known germline sequence. In some contexts, somatic mutations that are not critical to a desired property of the antibody (e.g., binding to a uVPl or VP2 polypeptide), or that confer an undesirable property upon the antibody (e.g., an increased risk of immunogenicity in a subject administered the antibody), or both, may be replaced by the corresponding germline-encoded amino acid, or by a different amino acid, so that a desirable property of the antibody is improved or maintained and the undesirable property of the antibody is reduced or abrogated. Thus, in some embodiments, the antibody or antigen-binding fragment of the present disclosure comprises at least one more germline-encoded amino acid in a variable region as compared to a parent antibody or antigen-binding fragment, provided that the parent antibody or antigen binding fragment comprises one or more somatic mutations. Variable region and CDR amino acid sequences of exemplary anti-parvovirus antibodies of the present disclosure are provided in Table 1 herein.

Polynucleotide sequences and other information of these and related human IG alleles are available at, for example, IMGT.org (see e.g. www. imgt. org/IMGT_vquest/ analy si s).

In certain embodiments, an antibody or antigen-binding fragment comprises an amino acid modification (e.g., a substitution mutation) to remove an undesired risk of oxidation, deamidation, and/or isomerization.

Also provided herein are variant antibodies that comprise one or more amino acid alterations in a variable region (e.g., VH, VL, framework or CDR) as compared to a presently disclosed ("parent") antibody, wherein the variant antibody is capable of binding to a parvovirus antigen.

In some embodiments, a composition or combination is provided that comprises a first antibody or antigen-binding fragment, and a different, second antibody or antigen-binding fragment, wherein the first antibody or antigen-binding fragment binds to an epitope in uVPl and the second antibody or antigen-binding fragment binds to an epitope in VP2. In certain embodiments, the first antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigenbinding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A see also Figure 8A). In other embodiments, the first antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A see also Figure 8B), and the second antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A (see also Figure 8C). In some embodiments, the first antibody or antigen-binding fragment and/or the second antibody or antigen-binding fragment comprises a heavy chain comprising M428L and N434S mutations.

In certain embodiments, the first antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18, as shown in Table A (see also Figure 8 A). In other embodiments, the first antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (see also Figure 8C). In some embodiments, the first antibody or antigen-binding fragment and/or the second antibody or antigen-binding fragment comprises a heavy chain comprising M428L and N434S mutations.

In certain embodiments, an antibody or antigen-binding fragment of the present disclosure is monospecific (e.g., binds to a single epitope) or is multispecific (e.g., binds to multiple epitopes and/or target molecules). Antibodies and antigen binding fragments may be constructed in various formats. Exemplary antibody formats disclosed in Spiess et al., Mol. Immunol. 67(2):95 (2015), and in Brinkmann and Kontermann, mAbs 9(2): 182-212 (2017), which formats and methods of making the same are incorporated herein by reference and include, for example, Bispecific T cell Engagers (BiTEs), DARTs, Knobs-Into-Holes (KIH) assemblies, scFv-CH3-KIH assemblies, KIH Common Light-Chain antibodies, TandAbs, Triple Bodies, TriBi Minibodies, Fab-scFv, scFv-CH-CL-scFv, F(ab')2-scFv2, tetravalent HCabs, Intrabodies, CrossMabs, Dual Action Fabs (DAFs) (two-in-one or four-in-one), DutaMabs, DT-IgG, Charge Pairs, Fab-arm Exchange, SEEDbodies, Triomabs, LUZ-Y assemblies, Fcabs, Kk-bodies, orthogonal Fabs, DVD-Igs (e.g., US Patent No. 8,258,268, which formats are incorporated herein by reference in their entirety), IgG(H)-scFv, scFv-(H)IgG, IgG(L)-scFv, scFv-(L)IgG, IgG(L,H)-Fv, IgG(H)-V, V(H)- IgG, IgG(L)-V, V(L)-IgG, KIH IgG-scFab, 2scFv-IgG, IgG-2scFv, scFv4-Ig, Zybody, and DVLIgG (four-in-one), as well as so-called FIT-Ig (e.g., PCT Publication No. WO 2015/103072, which formats are incorporated herein by reference in their entirety), so- called WuxiBody formats (e.g., PCT Publication No. WO 2019/057122, which formats are incorporated herein by reference in their entirety), and so-called In-Elbow-Insert Ig formats (lELIg; e.g., PCT Publication Nos. WO 2019/024979 and WO 2019/025391, which formats are incorporated herein by reference in their entirety).

In certain embodiments, the antibody or antigen-binding fragment comprises two or more of VH domains, two or more VL domains, or both (z.e., two or more VH domains and two or more VL domains). In particular embodiments, an antigen-binding fragment comprises the format (N-terminal to C-terminal direction) VH-linker- VL- linker-VH-linker-VL, wherein the two VH sequences can be the same or different and the two VL sequences can be the same or different. Such linked scFvs can include any combination of VH and VL domains arranged to bind to a given target, and in formats comprising two or more VH and/or two or more VL, one, two, or more different eptiopes or antigens may be bound. It will be appreciated that formats incorporating multiple antigen-binding domains may include VH and/or VL sequences in any combination or orientation. For example, the antigen-binding fragment can comprise the format VL-linker-VH-linker-VL-linker-VH, VH-linker-VL-linker-VL-linker-VH, or VL-linker- VH-linker- VH-linker- VL .

Monospecific or multispecific antibodies or antigen-binding fragments of the present disclosure constructed comprise any combination of the VH and VL sequences and/or any combination of the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 sequences disclosed herein. A bispecific or multispecific antibody or antigenbinding fragment may, in some embodiments, comprise one, two, or more antigenbinding domains (e.g., a VH and a VL) of the instant disclosure. Two or more binding domains may be present that bind to the same or a different epitope, and a bispecific or multispecific antibody or antigen-binding fragment as provided herein can, in some embodiments, comprise a further parvovirus-specific binding domain, and/or can comprise a binding domain that binds to a different antigen or pathogen altogether.

In any of the presently disclosed embodiments, the antibody or antigen-binding fragment can be multispecific; e.g., bispecific, trispecific, or the like. In some embodiments, a multispecific antibody or antigen-binding fragment is provided that comprises the heavy and light chain CDRs of PAB5 and PAB18; or of PAB5 and PAA19. Also contemplated are multispecific antibodies or antigen-binding fragments comprising the VH and the VL of PAB5 and PAB18; or of P AB 5 and PAA19; or of PAB18 and PAA19. In some embodiments, the multispecific antibody or antigen-binding fragment comprises a heavy chain comprising M428L and N434S mutations.

In certain embodiments, the antibody or antigen-binding fragment comprises a Fc polypeptide, or a fragment thereof. The "Fc" fragment or Fc polypeptide comprises the carboxy -terminal portions (ie., the CH2 and CH3 domains of IgG) of both antibody H chains held together by disulfides. An Fc may comprise a dimer comprised of two Fc polypeptides (z.e., two CH2-CH3 polypeptides). Antibody "effector functions" refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody, and vary with the antibody isotype. Examples of antibody effector functions include: Clq binding and complement dependent cytotoxicity; Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; down regulation of cell surface receptors (e.g., B cell receptor); and B cell activation. As discussed herein, modifications (e.g., amino acid substitutions) may be made to an Fc domain in order to modify (e.g., improve, reduce, or ablate) one or more functionality of an Fc-containing polypeptide (e.g., an antibody of the present disclosure). Such functions include, for example, Fc receptor (FcR) binding, antibody half-life modulation (e.g., by binding to FcRn), ADCC function, protein A binding, protein G binding, and complement binding. Amino acid modifications that modify (e.g., improve, reduce, or ablate) Fc functionalities include, for example, the T250Q/M428L, M252Y/S254T/T256E, H433K/N434F, M428L/N434S, M428L/N434A, E233P/L234V/L235A/G236 + A327G/A330S/P331S, E333A, S239D/A330L/I332E, P257I/Q311, K326W/E333S, S239D/I332E/G236A, N297Q, K322A, S228P, L235E + E318A/K320A/K322A, L234A/L235A (also referred to herein as "LALA"), and L234A/L235A/P329G mutations, which mutations are summarized and annotated in "Engineered Fc Regions", published by InvivoGen (2011) and available online at invivogen.com/PDF/review/review-Engineered-Fc-Regions- invivogen.pdf?utm_source=review&utm_medium=pdf&utm_ campaign=review&utm_content=Engineered-Fc-Regions, and are incorporated herein by reference.

For example, to activate the complement cascade, the Clq protein complex can bind to at least two molecules of IgGl or one molecule of IgM when the immunoglobulin molecule(s) is attached to the antigenic target (Ward, E. S., and Ghetie, V., Then Immunol. 2 (1995) 77-94). Burton, D. R., described (Mol. Immunol. 22 (1985) 161-206) that the heavy chain region comprising amino acid residues 318 to 337 is involved in complement fixation. Duncan, A. R., and Winter, G. (Nature 332 (1988) 738-740), using site directed mutagenesis, reported that Glu318, Lys320 and Lys322 form the binding site to Clq. The role of Glu318, Lys320 and Lys 322 residues in the binding of Clq was confirmed by the ability of a short synthetic peptide containing these residues to inhibit complement mediated lysis.

For example, FcR binding can be mediated by the interaction of the Fc moiety (of an antibody) with Fc receptors (FcRs), which are specialized cell surface receptors on cells including hematopoietic cells. Fc receptors belong to the immunoglobulin superfamily, and shown to mediate both the removal of antibody-coated pathogens by phagocytosis of immune complexes, and the lysis of erythrocytes and various other cellular targets (e.g. tumor cells) coated with the corresponding antibody, via antibody dependent cell mediated cytotoxicity (ADCC; Van de Winkel, J. G., and Anderson, C. L., J. Leukoc. Biol. 49 (1991) 511-524). FcRs are defined by their specificity for immunoglobulin classes; Fc receptors for IgG antibodies are referred to as FcyR, for IgE as FcsR, for IgA as FcaR and so on and neonatal Fc receptors are referred to as FcRn. Fc receptor binding is described for example in Ravetch, J. V, and Kinet, J. P, Annu. Rev. Immunol. 9 (1991) 457-492; Capel, P. J., et al., Immunomethods 4 (1994) 25-34; de Haas, M., et al., J Lab. Clin. Med. 126 (1995) 330-341; and Gessner, J. E., et al., Ann. Hematol. 76 (1998) 231-248.

Cross-linking of receptors by the Fc domain of native IgG antibodies (FcyR) triggers a wide variety of effector functions including phagocytosis, antibody-dependent cellular cytotoxicity, and release of inflammatory mediators, as well as immune complex clearance and regulation of antibody production. Fc moi eties providing crosslinking of receptors (e.g., FcyR) are contemplated herein. In humans, three classes of FcyR have been characterized to-date, which are: (i) FcyRI (CD64), which binds monomeric IgG with high affinity and is expressed on macrophages, monocytes, neutrophils and eosinophils; (ii) FcyRII (CD32), which binds complexed IgG with medium to low affinity, is widely expressed, in particular on leukocytes, is believed to be a central player in antibody-mediated immunity, and which can be divided into FcyRIIA, FcyRIIB and FcyRIIC, which perform different functions in the immune system, but bind with similar low affinity to the IgG-Fc, and the ectodomains of these receptors are highly homologuous; and (iii) FcyRIII (CD 16), which binds IgG with medium to low affinity and has been found in two forms: FcyRIIIA, which has been found on NK cells, macrophages, eosinophils, and some monocytes and T cells, and is believed to mediate ADCC; and FcyRIIIB, which is highly expressed on neutrophils.

FcyRIIA is found on many cells involved in killing (e.g. macrophages, monocytes, neutrophils) and seems able to activate the killing process. FcyRIIB seems to play a role in inhibitory processes and is found on B-cells, macrophages and on mast cells and eosinophils. Importantly, it has been shown that 75% of all FcyRIIB is found in the liver (Ganesan, L. P. et al., 2012: "FcyRIIb on liver sinusoidal endothelium clears small immune complexes," Journal of Immunology 189: 4981-4988). FcyRIIB is abundantly expressed on Liver Sinusoidal Endothelium, called LSEC, and in Kupffer cells in the liver and LSEC are the major site of small immune complexes clearance (Ganesan, L. P. et al., 2012: FcyRIIb on liver sinusoidal endothelium clears small immune complexes. Journal of Immunology 189: 4981-4988).

In some embodiments, the antibodies disclosed herein and the antigen-binding fragments thereof comprise an Fc polypeptide or fragment thereof for binding to FcyRIIb, in particular an Fc region, such as, for example IgG-type antibodies. Moreover, it is possible to engineer the Fc moiety to enhance FcyRIIB binding by introducing the mutations S267E and L328F as described by Chu, S. Y. et al., 2008: Inhibition of B cell receptor-mediated activation of primary human B cells by coengagement of CD19 and FcgammaRIIb with Fc-engineered antibodies. Molecular Immunology 45, 3926-3933. Thereby, the clearance of immune complexes can be enhanced (Chu, S., et al., 2014: Accelerated Clearance of IgE In Chimpanzees Is Mediated By Xmab7195, An Fc-Engineered Antibody With Enhanced Affinity For Inhibitory Receptor FcyRIIb. Am J Respir Crit, American Thoracic Society International Conference Abstracts). In some embodiments, the antibodies of the present disclosure, or the antigen binding fragments thereof, comprise an engineered Fc moiety with the mutations S267E and L328F, in particular as described by Chu, S. Y. et al., 2008: Inhibition of B cell receptor-mediated activation of primary human B cells by coengagement of CD19 and FcgammaRIIb with Fc-engineered antibodies. Molecular Immunology 45, 3926-3933.

On B cells, FcyRIIB may function to suppress further immunoglobulin production and isotype switching to, for example, the IgE class. On macrophages, FcyRIIB is thought to inhibit phagocytosis as mediated through FcyRIIA. On eosinophils and mast cells, the B form may help to suppress activation of these cells through IgE binding to its separate receptor.

Regarding FcyRI binding, modification in native IgG of at least one of E233- G236, P238, D265, N297, A327 and P329 reduces binding to FcyRI. IgG2 residues at positions 233-236, substituted into corresponding positions IgGl and IgG4, reduces binding of IgGl and IgG4 to FcyRI by 10³-fold and eliminated the human monocyte response to antibody-sensitized red blood cells (Armour, K. L., et al. Eur J. Immunol. 29 (1999) 2613-2624).

Regarding FcyRII binding, reduced binding for FcyRIIA is found, e.g., for IgG mutation of at least one of E233-G236, P238, D265, N297, A327, P329, D270, Q295, A327, R292 and K414.

Two allelic forms of human FcyRIIA are the "Hl 31 " variant, which binds to IgGl Fc with higher affinity, and the "R131" variant, which binds to IgGl Fc with low affinityer. See, e.g., Bruhns et al., Blood 773:3716-3725 (2009).

Regarding FcyRIII binding, reduced binding to FcyRIIIA is found, e.g., for mutation of at least one of E233-G236, P238, D265, N297, A327, P329, D270, Q295, Ki l, S239, E269, E293, Y296, V303, A327, K338 and D376. Mapping of the binding sites on human IgGl for Fc receptors, the above-mentioned mutation sites, and methods for measuring binding to FcyRI and FcyRIIA, are described in Shields, R. L., et al., J. Biol. Chem. 276 (2001) 6591-6604.

Two allelic forms of human FcyRIIIA are the "Fl 58" variant, which binds to IgGl Fc with lower affinity, and the "VI 58" variant, which binds to IgGl Fc with higher affinity. See, e.g., Bruhns et al., Blood 773:3716-3725 (2009).

Regarding binding to FcyRII, two regions of native IgG Fc appear to be involved in interactions between FcyRIIs and IgGs, namely (i) the lower hinge site of IgG Fc, in particular amino acid residues L, L, G, G (234 - 237, EU numbering), and (ii) the adjacent region of the CH2 domain of IgG Fc, in particular a loop and strands in the upper CH2 domain adjacent to the lower hinge region, e.g. in a region of P331 (Wines, B.D., et al., J. Immunol. 2000; 164: 5313 - 5318). Moreover, FcyRI appears to bind to the same site on IgG Fc, whereas FcRn and Protein A bind to a different site on IgG Fc, which appears to be at the CH2-CH3 interface (Wines, B.D., et al., J. Immunol. 2000; 164: 5313 - 5318).

Also contemplated are mutations that increase binding affinity of an Fc polypeptide or fragment thereof of the present disclosure to a (i.e., one or more) Fey receptor (e.g., as compared to a reference Fc polypeptide or fragment thereof or containing the same that does not comprise the mutation(s)). See, e.g., Delillo and Ravetch, Cell 161(5): 1035-1045 (2015) and Ahmed et al., J. Struc. Biol. 194(1):78 (2016), the Fc mutations and techniques of which are incorporated herein by reference.

In any of the herein disclosed embodiments, an antibody or antigen-binding fragment can comprise a Fc polypeptide or fragment thereof comprising a mutation selected from G236A; S239D; A330L; and I332E; or a combination comprising any two or more of the same; e.g., S239D/I332E; S239D/A330L/I332E; G236A/S239D/I332E; G236A/A330L/I332E (also referred to herein as "GAALIE"); or G236A/S239D/A330L/I332E. In some embodiments, the Fc polypeptide or fragment thereof does not comprise S239D. In some embodiments, the Fc polypeptide or fragment thereof comprises S at position 239 (EU numbering). In certain embodiments, the Fc polypeptide or fragment thereof may comprise or consist of at least a portion of an Fc polypeptide or fragment thereof that is involved in FcRn binding. In certain embodiments, the Fc polypeptide or fragment thereof comprises one or more amino acid modifications that improve binding affinity for (e.g., enhance binding to) FcRn (e.g., at a pH of about 6.0) and, in some embodiments, thereby extend in vivo half-life of a molecule comprising the Fc polypeptide or fragment thereof (e.g., as compared to a reference Fc polypeptide or fragment thereof or antibody that is otherwise the same but does not comprise the modification(s)). In certain embodiments, the Fc polypeptide or fragment thereof comprises or is derived from a IgG Fc and a half-life-extending mutation comprises any one or more of: M428L; N434S; N434H; N434A; N434S; M252Y; S254T; T256E; T250Q; P257I Q311I; D376V; T307A; E380A (EU numbering). In certain embodiments, a half-life- extending mutation comprises M428L/N434S (also referred to herein as "MLNS", "LS", "_LS", and "-LS"). In certain embodiments, a half-life-extending mutation comprises M252Y/S254T/T256E. In certain embodiments, a half-life-extending mutation comprises T250Q/M428L. In certain embodiments, a half-life-extending mutation comprises P257I/Q311I. In certain embodiments, a half-life-extending mutation comprises P257I/N434H. In certain embodiments, a half-life-extending mutation comprises D376V/N434H. In certain embodiments, a half-life-extending mutation comprises T307A/E380A/N434A. In certain embodiments, a half-life- extending mutation comprises M428L/N434A.

In some embodiments, an antibody or antigen-binding fragment includes a Fc moiety that comprises the substitution mtuations M428L/N434S or M428L/N434A. In some embodiments, an antibody or antigen-binding fragment includes a Fc polypeptide or fragment thereof that comprises the substitution mtuations G236A/A330L/I332E. In certain embodiments, an antibody or antigen-binding fragment includes a (e.g., IgG) Fc moiety that comprises a G236A mutation, an A330L mutation, and a I332E mutation (GAALIE), and does not comprise a S239D mutation (e.g., comprises a native S at position 239). In particular embodiments, an antibody or antigen-binding fragment includes an Fc polypeptide or fragment thereof that comprises the substitution mutations: M428L/N434S (or M428L/N434A) and G236A/A330L/I332E, and optionally does not comprise S239D (e.g., comprises S at 239). In certain embodiments, an antibody or antigen-binding fragment includes a Fc polypeptide or fragment thereof that comprises the substitution mutations: M428L/N434S (or M428L/N434A) and G236A/S239D/A330L/I332E.

In certain embodiments, the antibody or antigen-binding fragment comprises a mutation that alters glycosylation, wherein the mutation that alters glycosylation comprises N297A, N297Q, or N297G, and/or the antibody or antigen-binding fragment is partially or fully aglycosylated and/or is partially or fully afucosylated. Host cell lines and methods of making partially or fully aglycosylated or partially or fully afucosylated antibodies and antigen-binding fragments are known (see, e.g., PCT Publication No. WO 2016/181357; Suzuki et al. Clin. Cancer Res. 73(6):1875-82 (2007); Huang et al. MAbs 6 1-12 (2018)).

An antibody or antigen-binding fragment of the present disclosure can be fucosylated (e.g., comprising one or more fucosyl moiety, and typically comprising a native (wild-type) fucosylation pattern or a fucosylation pattern that includes one or more additional, or fewer, fucosyl moieties as compared to native), or can be afucosylated. In particular, native IgGl antibodies carry a glycan site at N297, and this is typically the only site where a core fucose moiety may be found in the antibody, though some glycan sites may arise through mutation (e.g. in the variable domains) during antibody development. Fucosylation of an Fc polypeptide or fragment thereof, or of an antibody, can be effected by introducing amino acid mutations to introduce or disrupt a fucosylation site (e.g. a mutation at N297, such as N297Q or N297A, to disrupt formation of a glycan that can include a core fucose moiety), though typically it is preferred to maintain N297 and the glycan thereof, such as by expressing the polypeptide in a host cell which has been genetically engineered to lack the ability (or have an inhibited or compromised ability) to fucosylate the polypeptide; by expressing the polypeptide under conditions in which a host cell is impaired in its ability to fucosylate the polypeptide (e.g., in the presence of 2-fluoro-L-fucose (2FF)), or the like. An afucosylated polypeptide can comprise no fucose moieties, or substantially no fucose moieties, and/or can be expressed by a host cell that is genetically engineered to lack the ability (or have an inhibited or compromised ability) to fucosylate the polypeptide and/or can be expressed under conditions in which a host cell is impaired in its ability to fucosylate the polypeptide (e.g., in the presence of 2-fluoro-L-fucose (2FF)). In some embodiments, a polypeptide does not comprise a core fucose moiety at Asn297. In some embodiments, afucosylated polypeptides have increased binding to FcyRIIIA. In some contexts, addition of 2FF to a culture media comprising host cells expressing an antibody results in about 85% or more of the antibodies not carrying a fucose moiety. Accordingly, a plurality of antibodies may be described as “afucosylated” when the plurality was produced in the presence of 2FF or like reagent. In some contexts, a plurality of polypeptides or antibodies may be described as, for example, afucosylated, meaning that about 85% or more of the single polypeptide or antibody molecules of the plurality do not comprise a fucose moiety. In certain preferred embodiments, an afucosylated antibody or polypeptide or a population or a plurality thereof comprises an asparagine (N) at EU position 297. Fucosylation or lack thereof can be assessed using, for example, mass spectrometry (e.g. Electrospray mass spectrometry (ESI-MS)). In some embodiments, compositions are provided that comprise a plurality of any one or more of the presently disclosed polypeptides, wherein the composition comprises afucosylated polypeptides.

In certain embodiments, the antibody or antigen-binding fragment is capable of eliciting continued protection in vivo in a subject even once no detectable levels of the antibody or antigen-binding fragment can be found in the subject (z.e., when the antibody or antigen-binding fragment has been cleared from the subject following administration). Such protection is referred to herein as a vaccinal effect. Without wishing to be bound by theory, it is believed that dendritic cells can internalize complexes of antibody and antigen and thereafter induce or contribute to an endogenous immune response against antigen. In certain embodiments, an antibody or antigenbinding fragment comprises one or more modifications, such as, for example, mutations in the Fc comprising G236A, A330L, and I332E, that are capable of activating dendritic cells that may induce, e.g., T cell immunity to the antigen. In certain embodiments, an antibody or antigen-binding fragment fo the present disclosure comprises an Fc variant selected from the Fc variants summarized in Table C (see also PCT Publication No. WO 2022/251119). In certain embodiments, the Fc variant, or the antibody or antigen-binding fragment, is fucosylated. In other embodiments, the Fc variant, or the antibody or antigen-binding fragment, is afucosylated.

Table C. Certain Fc Variants (fucosylated unless otherwise indicated) and

Properties Thereof

In some embodiments, an anti-parvovirus antibody or antigen-binding fragment is provided that comprises, in a(n e.g. human) IgGl heavy chain, the amino acid mutation(s) set forth in any one of (i)-(xviii): (i) G236A, L328V, and Q295E; (ii) G236A, P230A, and Q295E; (iii) G236A, R292P, and I377N; (iv) G236A, K334A, and Q295E; (v) G236S, R292P, and Y300L; (vi) G236A and Y300L; (vii) G236A, R292P, and Y300L; (viii) G236S, G420V, G446E, and L309T; (ix) G236A and R292P; (x) R292P and Y300L; (xi) G236A and R292P; (xii) Y300L; (xiii) E345K, G236S, L235Y, and S267E; (xiv) E272R, L309T, S219Y, and S267E; (xv) G236Y; (xvi) G236W; (xvii) F243L, G446E, P396L, and S267E; (xviii) G236A, S239D, and H268E, wherein the numbering of amino acid residues is according to the EU index as set forth in Kabat. In certain embodiments, the antibody or antigen-binding fragment is afucosylated. In some embodiments, the antibody or antigen-binding fragment further comprises one or more mutation that enhances binding to a human FcRn, such as M428L and N434S mutations or M428L and N434A mutations (EU numbering) or any other mutation(s) that enhance binding to a human FcRn, such as those described herein. In certain embodiments, the antibody or antigen-binding fragment is afucosylated.

In any of the presently disclosed embodiments, the antibody or antigen-binding fragment comprises a Fc polypeptide or a fragment thereof, including a CH2 (or a fragment thereof, a CH3 (or a fragment thereof), or a CH2 and a CH3, wherein the CH2, the CH3, or both can be of any isotype and may contain amino acid substitutions or other modifications as compared to a corresponding wild-type CH2 or CH3, respectively. In certain embodiments, a Fc of the present disclosure comprises two CH2-CH3 polypeptides that associate to form a dimer. In any of the presently disclosed embodiments, the antibody or antigen-binding fragment can be monoclonal. The term "monoclonal antibody" (mAb) as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, z.e., individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present, in some cases in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to polyclonal antibody preparations that include different antibodies directed against different epitopes, each monoclonal antibody is directed against a single epitope of the antigen. In addition to their specificity, the monoclonal antibodies are advantageous in that they may be synthesized uncontaminated by other antibodies. The term "monoclonal" is not to be construed as requiring production of the antibody by any particular method. For example, monoclonal antibodies useful in the present invention may be prepared by the hybridoma methodology first described by Kohler et al., Nature 256 :495 (1975), or may be made using recombinant DNA methods in bacterial, eukaryotic animal, or plant cells (see, e.g., U.S. Pat. No. 4,816,567). Monoclonal antibodies may also be isolated from phage antibody libraries using the techniques described in Clackson et al., Nature, 352:624-628 (1991) and Marks et al., J. Mol. Biol., 222:581-597 (1991), for example. Monoclonal antibodies may also be obtained using methods disclosed in PCT Publication No. WO 2004/076677A2.

Antibodies and antigen-binding fragments of the present disclosure include "chimeric antibodies" in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (see, U.S. Pat. Nos. 4,816,567; 5,530,101 and 7,498,415; and Morrison et al., Proc. Natl. Acad. Sci. USA, 57:6851-6855 (1984)). For example, chimeric antibodies may comprise human and non-human residues. Furthermore, chimeric antibodies may comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. For further details, see Jones et al.. Nature 321 :522-525 (1986); Riechmann et al., Nature 332:323- 329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992). Chimeric antibodies also include primatized and humanized antibodies.

A "humanized antibody" is generally considered to be a human antibody that has one or more amino acid residues introduced into it from a source that is non-human. These non-human amino acid residues are typically taken from a variable domain. Humanization may be performed following the method of Winter and co-workers (Jones et al., Nature, 321 :522-525 (1986); Reichmann et al., Nature, 332:323-327 (1988); Verhoeyen et al., Science, 239: 1534-1536 (1988)), by substituting non-human variable sequences for the corresponding sequences of a human antibody. Accordingly, such "humanized" antibodies are chimeric antibodies (U.S. Pat. Nos. 4,816,567; 5,530,101 and 7,498,415) wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In some instances, a "humanized" antibody is one which is produced by a non-human cell or animal and comprises human sequences, e.g., He domains.

A "human antibody" is an antibody containing only sequences that are present in an antibody that is produced by a human (i.e., sequences that are encoded by human antibody-encoding genes). However, as used herein, human antibodies may comprise residues or modifications not found in a naturally occurring human antibody (e.g., an antibody that is isolated from a human), including those modifications and variant sequences described herein. These are typically made to further refine or enhance antibody performance. In some instances, human antibodies are produced by transgenic animals. For example, see U.S. Pat. Nos. 5,770,429; 6,596,541 and 7,049,426.

In certain embodiments, an antibody or antigen-binding fragment of the present disclosure is chimeric, humanized, or human.

In some embodiments, various pharmacokinetic ("PK") parameters are used to describe or characterize the antibodies or antigen-binding fragments provided herein. Details regarding collection of antibody serum concentrations for purpose of evaluating PK parameters are described in association with the Examples herein. The term "ti/2" or "half-life" refers to the elimination half-life of the antibody or antigen-binding fragment included in the pharmaceutical composition administered to a subject. The term "Clast" generally refers to the last measurable plasma concentration (z.e., subsequent thereto, the substance is not present at a measurable concentration in plasma).

Also provided are fusion proteins that comprise an antibody or antigen-binding fragment of the present disclosure. In some embodiments, a fusion protein comprises (i) an extracellular component comprising the antibody or antigen-binding fragment, (ii) a transmembrane component, and (iii) an intracellular component comprising one or more signaling domains (e.g., from CD3(^, CD28, 4-1BB, and/or TLR8). In some embodiments, a fusion protein comprises a chimeric antigen receptor. In some embodiments, a fusion protein comprises a chimeric engulfment receptor (see, e.g., Corey et al., Molecular Therapy Methods & Clinical Development 28: 1-10 (2023); doi.org/10.1016/j.omtim.2022.11.004).

Polynucleotides, Vectors, and Host cells

In another aspect, the present disclosure provides isolated polynucleotides that encode any of the presently disclosed antibodies or an antigen-binding fragment thereof, or a portion thereof (e.g., a CDR, a VH, a VL, a heavy chain, or a light chain, or a heavy chain and a light chain), or that encode a presently disclosed polypeptide.

In certain embodiments, the polynucleotide comprises deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), wherein the RNA optionally comprises messenger RNA (mRNA).

In some embodiments, the polynucleotide comprises a modified nucleoside, a cap-1 structure, a cap-2 structure, or any combination thereof. In certain embodiments, the polynucleotide comprises a pseudouridine, a N6-methyladenonsine, a 5- methylcytidine, a 2-thiouridine, or any combination thereof. In some embodiments, the pseudouridine comprises N1 -methylpseudouridine.

In certain embodiments, a polynucleotide comprises a polynucleotide having at least 50% (e.g., 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more) identity to the polynucleotide sequence set forth in any one or more of SEQ ID NOs.: 6, 11, 16, 21, 26, and 31. In certain embodiments, a polynucleotide comprises a polynucleotide having at least 50%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or more) identity to the polynucleotide sequence set forth in any one or more of SEQ ID NOs.: 6, 11, 16, 21, 26, and 31.

In certain embodiments, the polynucleotide is codon-optimized for expression in a host cell (e.g., a human cell, or a CHO cell). Once a coding sequence is known or identified, codon optimization can be performed using known techniques and tools, e.g., using the GenScript® OptimiumGene™ tool, or the like). Codon-optimized sequences include sequences that are partially codon-optimized (z.e., one or more codon is optimized for expression in the host cell) and those that are fully codon-optimized.

In particular embodiments, a polynucleotide comprises the polynucleotide sequence of any one or more of SEQ ID NO.:6, 11, 16, 21, 26, and 31.

In certain embodiments, a polynucleotide comprises the polynucleotide sequence of SEQ ID NO. :6 and the polynucleotide sequence of SEQ ID NO. : 11.

In certain embodiments, a polynucleotide comprises the polynucleotide sequence of SEQ ID NO. : 16 and the polynucleotide sequence of SEQ ID NO. :21.

In certain embodiments, a polynucleotide comprises the polynucleotide sequence of SEQ ID NO. :26 and the polynucleotide sequence of SEQ ID NO. :31.

It will also be appreciated that polynucleotides encoding antibodies and antigenbinding fragments of the present disclosure may possess different nucleotide sequences while still encoding a same antibody or antigen-binding fragment due to, for example, the degeneracy of the genetic code, splicing, and the like.

In any of the presently disclosed embodiments, the polynucleotide can comprise deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). In some embodiments, the RNA comprises messenger RNA (mRNA).

Vectors are also provided, wherein the vectors comprise or contain a polynucleotide as disclosed herein (e.g., a polynucleotide that encodes an anti- parvovirus antibody or antigen-binding fragment). A vector can comprise any one or more of the vectors disclosed herein. In particular embodiments, a vector is provided that comprises a DNA plasmid construct encoding the antibody or antigen-binding fragment, or a portion thereof (e.g., so-called "DMAb"; see, e.g., Muthumani et al., J Infect Dis. 277(3):369-378 (2016); Muthumani et al., Hum Vaccin Immunother 9:2253- 2262 (2013)); Flingai et al., Sci Rep. 5: 12616 (2015); and Elliott et al., NPJ Vaccines 18 (2017), which antibody-coding DNA constructs and related methods of use, including administration of the same, are incorporated herein by reference). In certain embodiments, a DNA plasmid construct comprises a single open reading frame encoding a heavy chain and a light chain (or a VH and a VL) of the antibody or antigenbinding fragment, wherein the sequence encoding the heavy chain and the sequence encoding the light chain are optionally separated by polynucleotide encoding a protease cleavage site and/or by a polynucleotide encoding a self-cleaving peptide. In some embodiments, the substituent components of the antibody or antigen-binding fragment are encoded by a polynucleotide comprised in a single plasmid. In other embodiments, the substituent components of the antibody or antigen-binding fragment are encoded by a polynucleotide comprised in two or more plasmids (e.g., a first plasmid comprises a polynucleotide encoding a heavy chain, VH, or VH+CH1, and a second plasmid comprises a polynucleotide encoding the cognate light chain, or VL). In certain embodiments, a single plasmid comprises a polynucleotide encoding a heavy chain and/or a light chain from two or more antibodies or antigen-binding fragments of the present disclosure. An exemplary expression vector is pVaxl, available from Invitrogen®. A DNA plasmid of the present disclosure can be delivered to a subject by, for example, electroporation (e.g., intramuscular electroporation), or with an appropriate formulation (e.g., hyaluronidase).

In some embodiments, a method is provided that comprises administering to a subject a first polynucleotide (e.g., mRNA) encoding an antibody heavy chain, a VH, or a Fd (VH + CHI), and administering to the subject a second polynucleotide (e.g., mRNA) encoding the cognate antibody light chain or VL. In some embodiments, a polynucleotide (e.g., mRNA) is provided that encodes a heavy chain and a light chain of an antibody or antigen-binding fragment thereof. In some embodiments, a polynucleotide (e.g., mRNA) is provided that encodes two heavy chains and two light chains of an antibody or antigen-binding fragment thereof. See, e.g. Li, JQ., Zhang, ZR., Zhang, HQ. et al. Intranasal delivery of replicating mRNA encoding neutralizing antibody against SARS-CoV-2 infection in mice. Sig Transduct Target Ther 6, 369 (2021). https://doi.org/10.1038/s41392-021-00783-l, the antibodyencoding mRNA constructs, vectors, and related techniques of which are incorporated herein by reference. In some embodiments, a polynucleotide is delivered to a subject via an alphavirus replicon particle (VRP) delivery system. In some embodiments, a replicon comprises a modified VEEV replicon comprising two subgenomic promoters. In some embodiments, a polynucleotide or replicon can translate simultaneously the heavy chain (or VH, or VH+1) and the light chain (or VL) of an antibody or antigenbinding fragment thereof. In some embodiments, a method is provided that comprises delivering to a subject such a polynucleotide or replicon.

In a further aspect, the present disclosure also provides a host cell expressing an antibody or antigen-binding fragment according to the present disclosure; or comprising or containing a vector or polynucleotide according the present disclosure.

Examples of such cells include but are not limited to, eukaryotic cells, e.g., yeast cells, animal cells, insect cells, plant cells; and prokaryotic cells, including E. coli. In some embodiments, the cells are mammalian cells, such as human B cells. In certain such embodiments, the cells are a mammalian cell line such as CHO cells (e.g., DHFR- CHO cells (Urlaub et al., PNAS 77:4216 (1980)), human embryonic kidney cells (e.g., HEK293T cells), PER.C6 cells, Y0 cells, Sp2/0 cells. NS0 cells, human liver cells, e.g. Hepa RG cells, myeloma cells or hybridoma cells. Other examples of mammalian host cell lines include mouse sertoli cells (e.g., TM4 cells); monkey kidney CV1 line transformed by SV40 (COS-7); baby hamster kidney cells (BHK); African green monkey kidney cells (VERO-76); monkey kidney cells (CV1); human cervical carcinoma cells (HELA); human lung cells (W138); human liver cells (Hep G2); canine kidney cells (MDCK; buffalo rat liver cells (BRL 3 A); mouse mammary tumor (MMT 060562); TRI cells; MRC 5 cells; and FS4 cells. Mammalian host cell lines suitable for antibody production also include those described in, for example, Yazaki and

Wu, Methods in Molecular Biology, Vol. 248 (B. K. C. Lo, ed., Humana Press, Totowa, N.J.), pp. 255-268 (2003).

In certain embodiments, a host cell is a prokaryotic cell, such as an E. coli. The expression of peptides in prokaryotic cells such as E. coli is well established (see, e.g., Pluckthun, A. Bio/Technology 9:545-551 (1991). For example, antibodies may be produced in bacteria, in particular when glycosylation and Fc effector function are not needed. For expression of antibody fragments and polypeptides in bacteria, see, e.g., U.S. Pat. Nos. 5,648,237; 5,789,199; and 5,840,523.

In particular embodiments, the cell may be transfected with a vector according to the present description with an expression vector. The term "transfection" refers to the introduction of nucleic acid molecules, such as DNA or RNA (e.g., mRNA) molecules, into cells, such as into eukaryotic cells. In the context of the present description, the term "transfection" encompasses any method known to the skilled person for introducing nucleic acid molecules into cells, such as into eukaryotic cells, including into mammalian cells. Such methods encompass, for example, electroporation, lipofection, e.g., based on cationic lipids and/or liposomes, calcium phosphate precipitation, nanoparticle based transfection, virus based transfection, or transfection based on cationic polymers, such as DEAE-dextran or polyethylenimine, etc. In certain embodiments, the introduction is non-viral.

Moreover, host cells of the present disclosure may be transfected stably or transiently with a vector according to the present disclosure, e.g. for expressing an antibody, or an antigen-binding fragment thereof, according to the present disclosure. In such embodiments, the cells may be stably transfected with the vector as described herein. Alternatively, cells may be transiently transfected with a vector according to the present disclosure encoding an antibody or antigen-binding fragment as disclosed herein. In any of the presently disclosed embodiments, a polynucleotide may be heterologous to the host cell. Accordingly, the present disclosure also provides recombinant host cells that heterologously express an antibody or antigen-binding fragment of the present disclosure. For example, the cell may be of a species that is different to the species from which the antibody was fully or partially obtained (e.g., CHO cells expressing a human antibody or an engineered human antibody). In some embodiments, the cell type of the host cell does not express the antibody or antigen-binding fragment in nature. Moreover, the host cell may impart a post-translational modification (PTM; e.g., glycosylation or fucosylation), or a lack thereof, on the antibody or antigenbinding fragment that is not present in a native state of the antibody or antigen-binding fragment (or in a native state of a parent antibody from which the antibody or antigen binding fragment was engineered or derived). Such a PTM, or a lack thereof, may result in a functional difference (e.g., reduced immunogenicity). Accordingly, an antibody or antigen-binding fragment of the present disclosure that is produced by a host cell as disclosed herein may include one or more post-translational modification that is distinct from the antibody (or parent antibody) in its native state (e.g., a human antibody produced by a host cell can comprise one or more post-translational modification, or can include fewer post-translational modification(s), such that it is distinct from the antibody when isolated from the human and/or produced by the native human B cell or plasma cell).

Insect cells useful expressing a binding protein of the present disclosure are known in the art and include, for example, Spodoptera frugipera Sf9 cells, Trichoplusia ni BTI-TN5B1-4 cells, and Spodoptera frugipera SfSWTOl "Mimic™" cells. See, e.g., Palmberger et al., J. Biotechnol. 753(3-4): 160-166 (2011). Numerous baculoviral strains have been identified which may be used in conjunction with insect cells, particularly for transfection of Spodoptera frugiperda cells.

Eukaryotic microbes such as filamentous fungi or yeast are also suitable hosts for cloning or expressing protein-encoding vectors, and include fungi and yeast strains with "humanized" glycosylation pathways, resulting in the production of an antibody with a partially or fully human glycosylation pattern. See Gerngross, Nat. Biotech. 22: 1409-1414 (2004); Li et al., Nat. Biotech. 24:210-215 (2006). Plant cells can also be utilized as hosts for expressing an antibody or antigenbinding fragment of the present disclosure. For example, PLANTIBODIES™ technology (described in, for example, U.S. Pat. Nos. 5,959,177; 6,040,498; 6,420,548; 7,125,978; and 6,417,429) employs transgenic plants to produce antibodies.

In certain embodiments, the host cell comprises a mammalian cell. In particular embodiments, the host cell is a CHO cell, a HEK293 cell, a PER.C6 cell, a Y0 cell, a Sp2/0 cell, a NSO cell, a human liver cell, a myeloma cell, or a hybridoma cell.

In a related aspect, the present disclosure provides methods for producing an antibody, or antigen-binding fragment, wherein the methods comprise culturing a host cell of the present disclosure under conditions and for a time sufficient to produce the antibody, or the antigen-binding fragment. Methods useful for isolating and purifying recombinantly produced antibodies, by way of example, may include obtaining supernatants from suitable host cell/vector systems that secrete the recombinant antibody into culture media and then concentrating the media using a commercially available filter. Following concentration, the concentrate may be applied to a single suitable purification matrix or to a series of suitable matrices, such as an affinity matrix or an ion exchange resin. One or more reverse phase HPLC steps may be employed to further purify a recombinant polypeptide. These purification methods may also be employed when isolating an immunogen from its natural environment. Methods for large scale production of one or more of the isolated/recombinant antibody described herein include batch cell culture, which is monitored and controlled to maintain appropriate culture conditions. Purification of soluble antibodies may be performed according to methods described herein and known in the art and that comport with laws and guidelines of domestic and foreign regulatory agencies.

Compositions

Also provided herein are compositions that comprise a presently disclosed antibody, antigen-binding fragment, polypeptide, polynucleotide, vector, or host cell, singly or in any combination, and can further comprise a pharmaceutically acceptable carrier, excipient, or diluent. Such compositions, as well as carriers, excipients, and diluents, are discussed in further detail herein. In certain embodiments, a composition comprises a first vector comprising a first plasmid, and a second vector comprising a second plasmid, wherein the first plasmid comprises a polynucleotide encoding a heavy chain, VH, or VH+CH1, and a second plasmid comprises a polynucleotide encoding the cognate light chain or VL of the antibody or antigen-binding fragment thereof. In certain embodiments, a composition comprises a polynucleotide (e.g., mRNA) coupled to a suitable delivery vehicle or carrier. Exemplary vehicles or carriers for administration to a human subject include a lipid or lipid-derived delivery vehicle, such as a liposome, solid lipid nanoparticle, oily suspension, submicron lipid emulsion, lipid microbubble, inverse lipid micelle, cochlear liposome, lipid microtubule, lipid microcylinder, or lipid nanoparticle (LNP) or a nanoscale platform (see, e.g., Li et al. Wilery Interdiscip Rev. Nanomed Nanobiotechnol. 77(2):el530 (2019)). Principles, reagents, and techniques for designing appropriate mRNA and and formulating mRNA-LNP and delivering the same are described in, for example, Pardi et al. (J Control Release 277345-351 (2015)); Thess et al. Mol Ther 23: 1456-1464 (2015)); Thran et al. (EMBO Mol Med 9(10): 1434-1448 (2017); Kose et al. (Set. Immunol. 4 eaaw6647 (2019); and Sabnis et al. (Mol. Ther. 26: 1509-1519 (2018)), which techniques, include capping, codon optimization, nucleoside modification, purification of mRNA, incorporation of the mRNA into stable lipid nanoparticles (e.g., ionizable cationic lipid/phosphatidylcholine/cholesterol/PEG-lipid; ionizable lipid:distearoyl PC:cholesterol:polyethylene glycol lipid), and subcutaneous, intramuscular, intradermal, intravenous, intraperitoneal, and intratracheal administration of the same, are incorporated herein by reference.

In certain embodiments, a composition comprises a first antibody or antigenbinding fragment of the present disclosure and a second antibody or antigen-binding fragment of the present disclosure, wherein of the first antibody or antigen-binding fragment and the second antibody or antigen-binding fragment are different. The first antibody or antigen-binding fragment can be any anti-parvovirus antibody or antigenbinding fragment of the present disclosure, and the second antibody or antigen-binding fragment can be any other anti-parvovirus antibody or antigen-binding fragment of the present disclosure.

In certain embodiments, the first antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigenbinding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A (see also Figure 8A). In other embodiments, the first antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A (see also Figure 8C). In some embodiments, the first antibody or antigen-binding fragment and/or the second antibody or antigen-binding fragment comprises a heavy chain comprising M428L and N434S mutations.

In certain embodiments, the first antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18, as shown in Table A (see also Figure 8 A). In other embodiments, the first antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (see also Figure 8C). In some embodiments, the first antibody or antigen-binding fragment and/or the second antibody or antigen-binding fragment comprises a heavy chain comprising M428L and N434S mutations.

Methods and Uses

Also provided herein are methods for use of an antibody or antigen-binding fragment, nucleic acid, vector, cell, combination, or composition of the present disclosure in the diagnosis of infection (e.g., in a human subject, or in a sample obtained from a human subject). In some embodiments, a parvovirus infection comprises infection with B 19. In some embodiments, a parvovirus infection comprises a chronic infection.

Methods of diagnosis e.g., in vitro, ex vivo) may include contacting an antibody, antibody fragment (e.g., antigen binding fragment) with a sample. Such samples may be isolated from a subject, for example an isolated tissue sample taken from, for example, nasal passages, sinus cavities, salivary glands, lung, liver, pancreas, kidney, ear, eye, placenta, alimentary tract, heart, ovaries, pituitary, adrenals, thyroid, brain, skin or blood. The methods of diagnosis may also include the detection of an antigen/antibody complex, in particular following the contacting of an antibody or antibody fragment with a sample. Such a detection step can be performed at the bench, i.e. without any contact to the human or animal body. Examples of detection methods are well-known to the person skilled in the art and include, e.g., ELISA (enzyme-linked immunosorbent assay), including direct, indirect, and sandwich ELISA.

Also provided herein are methods of treating a subject using an antibody or antigen-binding fragment of the present disclosure, or a composition comprising the same (or a polynucleotide, vector, host cell, or combination as disclosed herein), wherein the subject has, is believed to have, or is at risk for having an infection by parvovirus. In some embodiments, a parvovirus infection comprises infection with Bl 9. In some embodiments, a parvovirus infection comprises a chronic parvovirus infection. "Treat," "treatment," or "ameliorate" refers to medical management of a disease, disorder, or condition of a subject (e.g., a human or non-human mammal, such as a primate, horse, cat, dog, goat, mouse, or rat). In general, an appropriate dose or treatment regimen comprising an antibody or composition of the present disclosure is administered in an amount sufficient to elicit a therapeutic or prophylactic benefit. Therapeutic or prophylactic/preventive benefit includes improved clinical outcome; lessening or alleviation of symptoms associated with a disease; decreased occurrence of symptoms; improved quality of life; longer disease-free status; diminishment of extent of disease, stabilization of disease state; delay or prevention of disease progression; remission; survival; prolonged survival; or any combination thereof. In certain embodiments, therapeutic or prophylactic/preventive benefit includes reduction or prevention of hospitalization for treatment of a parvovirus infection (z.e., in a statistically significant manner). In certain embodiments, therapeutic or prophylactic/preventive benefit includes a reduced duration of hospitalization for treatment of a parvovirus infection (z.e., in a statistically significant manner). In certain embodiments, therapeutic or prophylactic/preventive benefit includes a reduced or abrogated need for respiratory intervention, such as intubation and/or the use of a respirator device. In certain embodiments, therapeutic or prophylactic/preventive benefit includes reversing a late-stage disease pathology and/or reducing mortality.

A "therapeutically effective amount" or "effective amount" of an antibody, antigen-binding fragment, polynucleotide, vector, host cell, combination, or composition of this disclosure refers to an amount of the composition or molecule sufficient to result in a therapeutic effect, including improved clinical outcome; lessening or alleviation of symptoms associated with a disease; decreased occurrence of symptoms; improved quality of life; longer disease-free status; diminishment of extent of disease, stabilization of disease state; delay of disease progression; remission; survival; or prolonged survival in a statistically significant manner. When referring to an individual active ingredient, administered alone, a therapeutically effective amount refers to the effects of that ingredient or cell expressing that ingredient alone. When referring to a combination, a therapeutically effective amount refers to the combined amounts of active ingredients or combined adjunctive active ingredient with a cell expressing an active ingredient that results in a therapeutic effect, whether administered serially, sequentially, or simultaneously.

Accordingly, in certain embodiments, methods are provided for treating a parvovirus infection in a subject, wherein the methods comprise administering to the subject an effective amount of an antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition as disclosed herein.

In certain embodiments, a method comprises administering to a subject an effective amount of: a first antibody or antigen-binding fragment of the present disclosure and a second antibody or antigen-binding fragment of the present disclosure (or administering an effective amount of a composition comprising the same), wherein of the first antibody or antigen-binding fragment and the second antibody or antigenbinding fragment are different. The first antibody or antigen-binding fragment can be any anti-parvovirus antibody or antigen-binding fragment of the present disclosure, and the second antibody or antigen-binding fragment can be any other anti-parvovirus antibody or antigen-binding fragment of the present disclosure. In certain embodiments, the first antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A (see also Figure 8A). In other embodiments, the first antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A (see also Figure 8C). In some embodiments, the first antibody or antigen-binding fragment and/or the second antibody or antigen-binding fragment comprises a heavy chain comprising M428L and N434S mutations. In certain embodiments, the first antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18, as shown in Table A (see also Figure 8A). In other embodiments, the first antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (see also Figure 8B), and the second antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (see also Figure 8C). In some embodiments, the first antibody or antigen-binding fragment and/or the second antibody or antigenbinding fragment comprises a heavy chain comprising M428L and N434S mutations.

Subjects that can be treated by the present disclosure are, in general, human and other primate subjects, such as monkeys and apes for veterinary medicine purposes. Other model organisms, such as mice and rats, may also be treated according to the present disclosure. In any of the aforementioned embodiments, the subject may be a human subject. The subjects can be male or female and can be any suitable age, including infantjuvenile, adolescent, adult, and geriatric subjects.

A number of criteria are believed to contribute to high risk for severe symptoms or death associated with a parvovirus infection. These include, but are not limited to, age, occupation, general health, pre-existing health conditions, locale, and lifestyle habits. In some embodiments, a subject treated according to the present disclosure comprises one or more risk factors.

In certain embodiments, a human subject treated according to the present disclosure is an infant, a child, a young adult, an adult of middle age, or an elderly person. In certain embodiments, a human subject treated according to the present disclosure is less than 1 year old, or is 1 to 5 years old, or is between 5 and 125 years old (e.g., 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 125 years old, including any and all ages therein or therebetween). In certain embodiments, a human subject treated according to the present disclosure is 0- 19 years old, 20-44 years old, 45-54 years old, 55-64 years old, 65-74 years old, 75-84 years old, or 85 years old, or older. Persons of middle, and especially of elderly age are can be at particular risk. In particular embodiments, the human subject is 45-54 years old, 55-64 years old, 65-74 years old, 75-84 years old, or 85 years old, or older. In some embodiments, the human subject is male. In some embodiments, the human subject is female.

In some embodiments, a subject receiving treatment for parvovirus infection according to the present disclosure has, or is at risk for having, contracting, or developing: fifth disease (z.e., a rash illness caused by parvovirus B19 and most commonly seen in children, also called erythema infetiosum); pure red cell aplasia; an immunocompromised state; sickle cell disease; rheumatoid arthritis; hydrops fetalis; fetal death; polyarthralgia; aplastic crisis (e.g., with increased hematopoiesis); or any combination of the foregoing.

In some embodiments, a subject receiving treatment for parvovirus infection according to the present disclosure is pregnant, has a chronic parvovirus infection, or both. In some embodiments, a subject receiving treatment for parvovirus infection according to the present disclosure has previously received an immune globulin preparation comprising immune globulin from a host or hosts (e.g., human and/or equine) that had been exposed to a parvovirus.Prophylaxis of infection with parvovirus refers in particular to prophylactic settings, wherein the subject was not diagnosed with infection with parvovirus (either no diagnosis was performed or diagnosis results were negative) and/or the subject does not show or experience symptoms of infection with parvovirus. Prophylaxis of infection with parvovirus is particularly useful in subjects at greater risk of severe disease or complications when infected, such as pregnant women, children (such as children under 59 months), the elderly, individuals with chronic medical conditions (such as chronic cardiac, pulmonary, renal, metabolic, neurodevelopmental, liver or hematologic diseases) and individuals with immunosuppressive conditions (such as HIV/AIDS, receiving chemotherapy or steroids, or malignancy).

In certain embodiments, treatment is administered as peri-exposure or preexposure prophylaxis. In certain embodiments, treatment is administered as postexposure prophylaxis.

In therapeutic settings, in contrast, the subject is typically infected with parvovirus, diagnosed with parvovirus infection, and/or showing symptoms of parvovirus infection. Of note, the terms "treatment" and "therapy"/"therapeutic" of parvovirus infection can refer to (complete) cure as well as attenuation/reduction of parvovirus infection and/or related symptoms (e.g., attenuation/reduction of severity of infection and/or symptoms, number of symptoms, duration of infection and/or symptoms, or any combination thereof).

It will be understood that reference herein to a reduced number and/or severity of symptoms, which reduction results from administration of a presently disclosed pharmaceutical composition, describes a comparison with a reference subject who did not receive a disclosed pharmaceutical composition. A reference subject can be, for example, (i) the same subject during an earlier period of time, (ii) a subject of a same or a similar: age or age group; gender; pregnancy status; chronic medical condition (such as chronic cardiac, pulmonary, renal, metabolic, neurodevel opmental, liver or hematologic diseases) or lack thereof; and/or immunosuppressive condition or lack thereof; or (iii) a typical subject within a population (e.g., local, regional, or national, including of a same or similar age or age range and/or general state of health). Prophylaxis can be determined by, for example, the failure to develop a diagnosed parvovirus infection and/or the lack of symptoms associated with parvovirus infection.

In some embodiments, treatment and/or prevention comprises post-exposure prophylaxis.

Typical routes of administering the presently disclosed compositions include, without limitation, oral, topical, transdermal, inhalation, parenteral, sublingual, buccal, rectal, vaginal, and intranasal. The term "parenteral", as used herein, includes subcutaneous injections, intravenous, intramuscular, intrasternal injection or infusion techniques. In certain embodiments, administering comprises administering by a route that is selected from oral, intravenous, parenteral, intragastric, intrapleural, intrapulmonary, intrarectal, intradermal, intraperitoneal, intratumoral, subcutaneous, topical, transdermal, intracisternal, intrathecal, intranasal, and intramuscular. In particular embodiments, a method comprises orally administering the antibody, antigenbinding fragment, polynucleotide, vector, host cell, or composition to the subject.

Pharmaceutical compositions according to certain embodiments of the present invention are formulated so as to allow the active ingredients contained therein to be bioavailable upon administration of the composition to a patient. Compositions that will be administered to a subject or patient may take the form of one or more dosage units, where for example, a tablet may be a single dosage unit, and a container of a herein described an antibody or antigen-binding in aerosol form may hold a plurality of dosage units. Actual methods of preparing such dosage forms are known, or will be apparent, to those skilled in this art; for example, see Remington: The Science and Practice of Pharmacy, 20th Edition (Philadelphia College of Pharmacy and Science, 2000). The composition to be administered will, in any event, contain an effective amount of an antibody or antigen-binding fragment, polynucleotide, vector, host cell, , or composition of the present disclosure, for treatment of a disease or condition of interest in accordance with teachings herein.

A composition may be in the form of a solid or liquid. In some embodiments, the carrier(s) are particulate, so that the compositions are, for example, in tablet or powder form. The carrier(s) may be liquid, with the compositions being, for example, an oral oil, injectable liquid or an aerosol, which is useful in, for example, inhalatory administration. When intended for oral administration, the pharmaceutical composition is preferably in either solid or liquid form, where semi solid, semi liquid, suspension and gel forms are included within the forms considered herein as either solid or liquid.

As a solid composition for oral administration, the pharmaceutical composition may be formulated into a powder, granule, compressed tablet, pill, capsule, chewing gum, wafer or the like. Such a solid composition will typically contain one or more inert diluents or edible carriers. In addition, one or more of the following may be present: binders such as carboxymethylcellulose, ethyl cellulose, microcrystalline cellulose, gum tragacanth or gelatin; excipients such as starch, lactose or dextrins, disintegrating agents such as alginic acid, sodium alginate, Primogel, corn starch and the like; lubricants such as magnesium stearate or Sterotex; glidants such as colloidal silicon dioxide; sweetening agents such as sucrose or saccharin; a flavoring agent such as peppermint, methyl salicylate or orange flavoring; and a coloring agent. When the composition is in the form of a capsule, for example, a gelatin capsule, it may contain, in addition to materials of the above type, a liquid carrier such as polyethylene glycol or oil.

The composition may be in the form of a liquid, for example, an elixir, syrup, solution, emulsion or suspension. The liquid may be for oral administration or for delivery by injection, as two examples. When intended for oral administration, preferred compositions contain, in addition to the present compounds, one or more of a sweetening agent, preservatives, dye/colorant and flavor enhancer. In a composition intended to be administered by injection, one or more of a surfactant, preservative, wetting agent, dispersing agent, suspending agent, buffer, stabilizer and isotonic agent may be included. Liquid pharmaceutical compositions, whether they be solutions, suspensions or other like form, may include one or more of the following adjuvants: sterile diluents such as water for injection, saline solution, preferably physiological saline, Ringer’s solution, isotonic sodium chloride, fixed oils such as synthetic mono or diglycerides which may serve as the solvent or suspending medium, polyethylene glycols, glycerin, propylene glycol or other solvents; antibacterial agents such as benzyl alcohol or methyl paraben; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic. Physiological saline is a preferred adjuvant. An injectable pharmaceutical composition is preferably sterile.

A liquid composition intended for either parenteral or oral administration should contain an amount of an antibody or antigen-binding fragment as herein disclosed such that a suitable dosage will be obtained. Typically, this amount is at least 0.01% of the antibody or antigen-binding fragment in the composition. When intended for oral administration, this amount may be varied to be between 0.1 and about 70% of the weight of the composition. Certain oral pharmaceutical compositions contain between about 4% and about 75% of the antibody or antigen-binding fragment. In certain embodiments, pharmaceutical compositions and preparations according to the present invention are prepared so that a parenteral dosage unit contains between 0.01 to 10% by weight of antibody or antigen-binding fragment prior to dilution.

The composition may be intended for topical administration, in which case the carrier may suitably comprise a solution, emulsion, ointment or gel base. The base, for example, may comprise one or more of the following: petrolatum, lanolin, polyethylene glycols, bee wax, mineral oil, diluents such as water and alcohol, and emulsifiers and stabilizers. Thickening agents may be present in a composition for topical administration. If intended for transdermal administration, the composition may include a transdermal patch or iontophoresis device. The pharmaceutical composition may be intended for rectal administration, in the form, for example, of a suppository, which will melt in the rectum and release the drug. The composition for rectal administration may contain an oleaginous base as a suitable nonirritating excipient. Such bases include, without limitation, lanolin, cocoa butter and polyethylene glycol.

A composition may include various materials which modify the physical form of a solid or liquid dosage unit. For example, the composition may include materials that form a coating shell around the active ingredients. The materials that form the coating shell are typically inert, and may be selected from, for example, sugar, shellac, and other enteric coating agents. Alternatively, the active ingredients may be encased in a gelatin capsule. The composition in solid or liquid form may include an agent that binds to the antibody or antigen-binding fragment of the disclosure and thereby assists in the delivery of the compound. Suitable agents that may act in this capacity include monoclonal or polyclonal antibodies, one or more proteins or a liposome. The composition may consist essentially of dosage units that can be administered as an aerosol. The term aerosol is used to denote a variety of systems ranging from those of colloidal nature to systems consisting of pressurized packages. Delivery may be by a liquefied or compressed gas or by a suitable pump system that dispenses the active ingredients. Aerosols may be delivered in single phase, bi phasic, or tri phasic systems in order to deliver the active ingredient(s). Delivery of the aerosol includes the necessary container, activators, valves, subcontainers, and the like, which together may form a kit. One of ordinary skill in the art, without undue experimentation, may determine preferred aerosols.

It will be understood that compositions of the present disclosure also encompass carrier molecules for polynucleotides, as described herein (e.g., lipid nanoparticles, nanoscale delivery platforms, and the like).

The pharmaceutical compositions may be prepared by methodology well known in the pharmaceutical art. For example, a composition intended to be administered by injection can be prepared by combining a composition that comprises an antibody, antigen-binding fragment thereof, or antibody conjugate as described herein and optionally, one or more of salts, buffers and/or stabilizers, with sterile, distilled water so as to form a solution. A surfactant may be added to facilitate the formation of a homogeneous solution or suspension. Surfactants are compounds that non-covalently interact with the peptide composition so as to facilitate dissolution or homogeneous suspension of the antibody or antigen-binding fragment thereof in the aqueous delivery system.

In general, an appropriate dose and treatment regimen provide the composition(s) in an amount sufficient to provide therapeutic and/or prophylactic benefit (such as described herein, including an improved clinical outcome (e.g., a decrease in frequency, duration, or severity of diarrhea or associated dehydration, or inflammation, or longer disease-free and/or overall survival, or a lessening of symptom severity). For prophylactic use, a dose should be sufficient to prevent, delay the onset of, or diminish the severity of a disease associated with disease or disorder. Prophylactic benefit of the compositions administered according to the methods described herein can be determined by performing pre-clinical (including in vitro and in vivo animal studies) and clinical studies and analyzing data obtained therefrom by appropriate statistical, biological, and clinical methods and techniques, all of which can readily be practiced by a person skilled in the art.

Compositions are administered in an effective amount (e.g., to treat a parvovirus infection), which will vary depending upon a variety of factors including the activity of the specific compound employed; the metabolic stability and length of action of the compound; the age, body weight, general health, sex, and diet of the subject; the mode and time of administration; the rate of excretion; the drug combination; the severity of the particular disorder or condition; and the subject undergoing therapy. In certain embodiments, tollowing administration of therapies according to the formulations and methods of this disclosure, test subjects will exhibit about a 10% up to about a 99% reduction in one or more symptoms associated with the disease or disorder being treated as compared to placebo-treated or other suitable control subjects.

Generally, a therapeutically effective dose of an antibody or antigen binding fragment is (for a 70 kg mammal) from about 0.001 mg/kg (z.e., 0.07 mg) to about 100 mg/kg (z.e., 7.0 g); preferably a therapeutically effective dose is (for a 70 kg mammal) from about 0.01 mg/kg (z.e., 0.7 mg) to about 50 mg/kg (z.e., 3.5 g); more preferably a therapeutically effective dose is (for a 70 kg mammal) from about 1 mg/kg (z.e., 70 mg) to about 25 mg/kg (z.e., 1.75 g). For polynucleotides, vectors, host cells, and related compositions of the present disclosure, a therapeutically effective dose may be different than for an antibody or antigen-binding fragment.

In certain embodiments, a method comprises administering the antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition to the subject at 2, 3, 4, 5, 6, 7, 8, 9, 10 times, or more.

In certain embodiments, a method comprises administering the antibody, antigen-binding fragment, or composition to the subject a plurality of times, wherein a second or successive administration is performed at about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 24, about 48, about 74, about 96 hours, or more, following a first or prior administration, respectively.

In certain embodiments, a method comprises administering the antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition at least one time prior to the subject being infected by parvovirus.

Compositions comprising an antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition of the present disclosure may also be administered simultaneously with, prior to, or after administration of one or more other therapeutic agents, such as, for example, human immunoglobulin preparations (IVIG). Such combination therapy may include administration of a single pharmaceutical dosage formulation which contains a compound of the invention and one or more additional active agents, as well as administration of compositions comprising an antibody or antigen-binding fragment of the disclosure and each active agent in its own separate dosage formulation. For example, an antibody or antigen-binding fragment thereof as described herein and the other active agent can be administered to the patient together in a single oral dosage composition such as a tablet or capsule, or each agent administered in separate oral dosage formulations. Similarly, an antibody or antigenbinding fragment as described herein and the other active agent can be administered to the subject together in a single parenteral dosage composition such as in a saline solution or other physiologically acceptable solution, or each agent administered in separate parenteral dosage formulations. Where separate dosage formulations are used, the compositions comprising an antibody or antigen-binding fragment and one or more additional active agents can be administered at essentially the same time, z.e., concurrently, or at separately staggered times, z.e., sequentially and in any order; combination therapy is understood to include all these regimens.

In some embodiments, an antibody (or one or more nucleic acid, host cell, vector, or composition) is administered to a subject who has previously received one or more anti-inflammatory agent and/or one or more antiviral agent. In some embodiments, one or more anti-inflammatory agent and/or one or more antiviral agent is administered to a subject who has previously received an antibody (or one or more nucleic acid, host cell, vector, or composition).

In a related aspect, uses of the presently disclosed antibodies, antigen-binding fragments, vectors, host cells, and compositions (e.g., in the diagnosis, prophylaxis, and/or treatment of a parvovirus infection, in the manufacture of a medicament for preventing or treating a parvovirus infection) are provided.

In certain embodiments, an antibody, antigen-binding fragment, polynucleotide, vector, host cell, or composition is provided for use in a method of treating or preventing a parvovirus infection in a subject.

In certain embodiments, an antibody, antigen-binding fragment, or composition is provided for use in a method of manufacturing or preparing a medicament for treating or preventing a parvovirus infection in a subject.

The present disclosure also provides the following non-limiting enumerated Embodiments.

Embodiment 1. An anti -parvovirus antibody, or an antigen-binding fragment thereof.

Embodiment 2. The anti-parvovirus antibody or antigen-binding fragment of Embodiment 1, wherein the parvovirus comprises an erythrovirus, optionally wherein the parvovirus is an erythrovirus. Embodiment 3. The anti-parvovirus antibody or antigen-binding fragment of Embodiment 1 or 2, wherein the parvovirus comprises Bl 9, optionally wherein the parvovirus is Bl 9.

Embodiment 4. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, which binds to an epitope in B19 uVPl.

Embodiment 5. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-4, which binds to a peptide having the amino acid sequence TGTDLE (SEQ ID NO.:4).

Embodiment 6. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-4, which binds to a peptide having the amino acid sequence X1X2TDX3EX4 (SEQ ID NO.:5), wherein:

Xi is present or absent, and, if present, is any amino acid;

X2 is G or F, and is preferably G;

X3 is L or K, and is preferably K; and

X4 is present or absent, and, if present, is any amino acid except P.

Embodiment 7. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-6, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and/or

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

Embodiment 8. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-7, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)Hl, the CDRH2, and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and (ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

Embodiment 9. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-7, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.:20, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.:25, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

Embodiment 10. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-7 and 9, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.: 18, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.: 19, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.:23, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.:24, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

Embodiment 11. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-10, comprising the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.: 18-20 and 23-25, respectively.

Embodiment 12. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-11, comprising:

(i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 17; and/or

(ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:22.

Embodiment 13. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-12, comprising:

(i) a heavy chain variable domain (VH) comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 17; and

(ii) a light chain variable domain (VL) comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:22.

Embodiment 14. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, which binds to an epitope in B19 VP2.

Embodiment 15. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3 and 14, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:7; and/or

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO. : 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

Embodiment 16. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, and 15, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 7; and

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO. : 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

Embodiment 17. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3 and 14-15, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.: 10, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.: 15, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

Embodiment 18. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, 15, and 17, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.:8, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.:9, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.: 13, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.: 14, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

Embodiment 19. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3 and 14-18, comprising the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.:8-10 and 13-15, respectively.

Embodiment 20. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3 and 14-19, comprising:

(i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:7; and/or

(ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO. : 12.

Embodiment 21. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3 and 14-20, comprising:

(i) a heavy chain variable domain (VH) comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:7; and

(ii) a light chain variable domain (VL) comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 12. Embodiment 22. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3 and 14, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and/or

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

Embodiment 23. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, and 22, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and

(ii) in a/the light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, AbM, CCG, or AHo numbering system, or in accordance with any combination thereof.

Embodiment 24. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, and 22, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.:30, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions;

(ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.:35, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions. Embodiment 25. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, 22, and 24, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.:28, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.:29, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.:33, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.:34, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

Embodiment 26. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, and 22-25, comprising the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.:28-30 and 33-35, respectively.

Embodiment 27. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, and 22-26 comprising:

(i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:27; and/or

(ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:32. Embodiment 28. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-3, 14, and 22-27, comprising:

(i) a heavy chain variable domain (VH) comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:27; and

(ii) a light chain variable domain (VL) comprising, consisting essentially of, or consisting of, the amino acid sequence set forth in SEQ ID NO.:32.

Embodiment 29. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-28, wherein the anti -parvovirus antibody or antigenbinding fragment comprises a human antibody, a monoclonal antibody, a purified antibody, a single chain antibody, a Fab, a Fab’, a F(ab’)2, or Fv.

Embodiment 30. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-29, wherein the anti -parvovirus antibody or antigenbinding fragment is a multi-specific antibody or antigen-binding fragment, wherein, optionally, the antibody or antigen-binding fragment is a bi-specific antibody or antigen-binding fragment.

Embodiment 31. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-30, wherein the anti -parvovirus antibody or antigenbinding fragment comprises an (e.g., IgGl) Fc polypeptide or a fragment thereof.

Embodiment 32. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-31, which comprises a IgG, IgA, IgM, IgE, or IgD isotype.

Embodiment 33. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-32, which comprises an IgG isotype selected from IgGl, IgG2, IgG3, and IgG4.

Embodiment 34. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-33, which comprises an IgGl isotype.

Embodiment 35. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-34, which comprises an IgGlm3 allotype, an IgGlml7 allotype, an IgGl ml allotype, or any combination thereof. Embodiment 36. The anti-parvovirus antibody or antigen-binding fragment of Embodiment 31-35, wherein the Fc polypeptide or fragment thereof comprises:

(i) a mutation that increases binding affinity to a human FcRn (e.g., as measured using surface plasmon resonance (SPR) (e.g., Biacore, e.g., T200 instrument, using manufacturer’s protocols)), as compared to a reference Fc polypeptide that does not comprise the mutation; and/or

(ii) a mutation that increases binding affinity to a human FcyR (e.g., as measured using surface plasmon resonance (SPR) (e.g., Biacore, e.g., T200 instrument, using manufacturer’s protocols, and/or as measured using mesoscale discovery (MSD))) as compared to a reference Fc polypeptide that does not comprise the mutation.

Embodiment 37. The anti-parvovirus antibody or antigen-binding fragment of Embodiment 36, wherein the mutation that increases binding affinity to a human FcRn comprises: M428L; N434S; N434H; N434A; N434S; M252Y; S254T; T256E; T250Q; P257I; Q311I; D376V; T307A; E380A; or any combination thereof.

Embodiment 38. The anti-parvovirus antibody or antigen-binding fragment of Embodiment 36 or 37, wherein the mutation that increases binding affinity to a human FcRn comprises: (i) M428L/N434S; (ii) M252Y/S254T/T256E; (iii) T250Q/M428L; (iv) P257VQ311I; (v) P257I/N434H; (vi) D376V/N434H; (vii) T307A/E380A/N434A; (viii) M428L/N434A; or (ix) any combination of (i)-(viii).

Embodiment 39. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 36-38, wherein the mutation that increases binding affinity to a human FcRn comprises M428L/N434S or M428L/N434A.

Embodiment 40. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 36-38, wherein the mutation that enhances binding to a FcyR comprises S239D; I332E; A330L; G236A; or any combination thereof.

Embodiment 41. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 36-40, wherein the mutation that enhances binding to a FcyR comprises: (i) S239D/I332E; (ii) S239D/A330L/I332E; (iii) G236A/S239D/I332E; or (iv) G236A/A330L/I332E, wherein the Fc polypeptide or fragment thereof optionally comprises Ser at position 239. Embodiment 42. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-41, which comprises a mutation that alters glycosylation, wherein the mutation that alters glycosylation comprises N297A, N297Q, or N297G, and/or which is aglycosylated, and/or which is afucosylated.

Embodiment 43. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-42, which: is afucosylated; has been produced in a host cell that is incapable of fucosylation or that is inhibited in its ability to fucosylate a polypeptide; has been produced under conditions that inhibit fucosylation thereof by a host cell; or any combination thereof.

Embodiment 44. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-43, which is human, humanized, or chimeric.

Embodiment 45. An isolated polynucleotide encoding the anti -parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44, or encoding a VH, a heavy chain, a VL, and/or a light chain of the anti-parvovirus antibody or the antigen-binding fragment.

Embodiment 46. The polynucleotide of Embodiment 45, wherein the polynucleotide comprises deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), wherein the RNA optionally comprises messenger RNA (mRNA).

Embodiment 47. The polynucleotide of any one of Embodiments 45-46, comprising a modified nucleoside, a cap-1 structure, a cap-2 structure, or any combination thereof.

Embodiment 48. The polynucleotide of Embodiment 47, wherein the polynucleotide comprises a pseudouridine, a N6-methyladenonsine, a 5-methylcytidine, a 2-thiouridine, or any combination thereof.

Embodiment 49. The polynucleotide of Embodiment 48, wherein the pseudouridine comprises N1 -methylpseudouridine.

50. The polynucleotide of any one of Embodiments 45-49, which is codon- optimized for expression in a host cell.

Embodiment 51. The polynucleotide of Embodiment 50, wherein the host cell comprises a human cell. Embodiment 52. A recombinant vector comprising the polynucleotide of any one of Embodiments 45-51.

Embodiment 53. A host cell comprising the polynucleotide of any one of Embodiments 45-51 and/or the vector of Embodiment 52, wherein the polynucleotide is optionally heterologous to the host cell and/or wherein the host cell is capable of expressing the encoded antibody or antigen-binding fragment or polypeptide.

Embodiment 54. An isolated human B cell comprising the polynucleotide of any one of Embodiments 45-51 and/or the vector of Embodiment 52, wherein polynucleotide is optionally heterologous to the human B cell and/or wherein the human B cell is immortalized.

Embodiment 55. A composition comprising:

(i) the anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44;

(ii) the polynucleotide of any one of Embodiments 45-51;

(iii) the recombinant vector of Embodiment 52;

(iv) the host cell of Embodiment 53; and/or

(v) the human B cell of Embodiment 54, and a pharmaceutically acceptable excipient, carrier, or diluent.

Embodiment 56. The composition of Embodiment 55, comprising a first anti-parvovirus antibody or antigen-binding fragment and a second anti-parvovirus antibody or antigen-binding fragment, wherein each of the first antibody or antigenbinding fragment and the second antibody or antigen-binding fragment are different and are each according any one of Embodiments 1-44, wherein, preferably, the first antiparvovirus antibody or antigen-binding fragment binds to an epitope in B19 uVPl and the second anti-parvovirus antibody or antigen-binding fragment binds to an epitope in B19 VP2, wherein, optionally:

(i) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (z.e., comprises SEQ ID NOs.: 18-20 and 23-25), and the second antiparvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A (z.e., comprises SEQ ID NOs.:8-10 and 13-15);

(ii) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A, and the second anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A (z.e., comprises SEQ ID NOs.:28-30 and 33-35);

(iii) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (z.e., comprises SEQ ID NOs.: 17 and 22), and the second anti -parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18 (z.e., comprises SEQ ID NOs.:7 and 12), as shown in Table A; or

(iv) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A, and the second antiparvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (z.e., comprises SEQ ID NOs.:27 and 32).

Embodiment 57. A composition comprising the polynucleotide of any one of Embodiments 45-51 or the vector of Embodiment 52 encapsulated in a carrier molecule, wherein the carrier molecule optionally comprises a lipid, a lipid-derived delivery vehicle, such as a liposome, a solid lipid nanoparticle, an oily suspension, a submicron lipid emulsion, a lipid microbubble, an inverse lipid micelle, a cochlear liposome, a lipid microtubule, a lipid microcylinder, lipid nanoparticle (LNP), or a nanoscale platform.

Embodiment 58. A method of making an anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44, comprising culturing the host cell of Embodiment 53 or the human B cell of Embodiment 54 for a time and under conditions sufficient for the host cell or human B cell, respectively, to express the anti-parvovirus antibody or antigen-binding fragment.

Embodiment 59. The method of Embodiment 58, further comprising isolating the anti-parvovirus antibody or antigen-binding fragment. Embodiment 60. A method of treating or preventing a parvovirus infection in a subject, the method comprising administering to the subject an effective amount of:

(i) the anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44;

(ii) the polynucleotide of any one of Embodiments 45-51, wherein, optionally, the polynucleotide comprises mRNA;

(iii) the recombinant vector of Embodiment 52;

(iv) the host cell of Embodiment 53;

(v) the human B cell of Embodiment 54; and/or

(vi) the composition of any one of Embodiments 55-57, wherein, optionally, the method comprises administering to the subject an effective amount: of a first antibody or antigen-binding fragment and a second antibody or antigen-binding fragment, wherein, further optionally:

(a) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (z.e., comprises SEQ ID NOs.: 18-20 and 23-25), and the second antiparvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A (i.e., comprises SEQ ID NOs.:8-10 and 13-15);

(b) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A, and the second anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A i.e., comprises SEQ ID NOs.:28-30 and 33-35);

(c) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A i.e., comprises SEQ ID NOs.: 17 and 22), and the second anti -parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18 i.e., comprises SEQ ID NOs.:7 and 12), as shown in Table A; or (d) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A, and the second antiparvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (z.e., comprises SEQ ID NOs.:27 and 32).

Embodiment 61. The method of Embodiment 60, comprising administering a single dose of the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, or composition to the subject.

Embodiment 62. The method of Embodiment 60 or 61, comprising administering two or more doses of the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, or composition to the subject.

Embodiment 63. The method of any one of Embodiments 60-62, comprising administering the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, or composition intramuscularly, subcutaneously, or intravenously.

Embodiment 64. The method of any one of Embodiments 60-63, wherein the treatment and/or prevention comprises post-exposure prophylaxis.

Embodiment 65. The method of any one of Embodiments 60-64, wherein the subject has received, is receiving, or will receive an antiviral.

Embodiment 66. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44, the polynucleotide of any one of Embodiments 45-51, the recombinant vector of Embodiment 52, the host cell of Embodiment 53, the human B cell of Embodiment 54, and/or the composition of any one of Embodiments 55-57, for use in a method of treating or preventing a parvovirus infection in a subject wherein, optionally, the method comprises administering to the subject an effective amount: of a first antibody or antigen-binding fragment and a second antibody or antigen-binding fragment, wherein, further optionally:

(a) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (z.e., comprises SEQ ID NOs.: 18-20 and 23-25), and the second antiparvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A (i.e., comprises SEQ ID NOs.:8-10 and 13-15);

(b) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A, and the second anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A (i.e., comprises SEQ ID NOs.:28-30 and 33-35);

(c) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (i.e., comprises SEQ ID NOs.: 17 and 22), and the second anti -parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18 (i.e., comprises SEQ ID NOs.:7 and 12), as shown in Table A; or

(d) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A, and the second antiparvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (z.e., comprises SEQ ID NOs.:27 and 32).

Embodiment 67. The anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44, the polynucleotide of any one of Embodiments 45-51, the recombinant vector of Embodiment 52, the host cell of Embodiment 53, the human B cell of Embodiment 54, and/or the composition of any one of Embodiments 55-57, for use in the preparation of a medicament for the treatment or prevention of a parvovirus infection in a subject, wherein, optionally, the medicament comprises an effective amount: of a first antibody or antigen-binding fragment and a second antibody or antigen-binding fragment, wherein, further optionally:

(a) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A (i.e., comprises SEQ ID NOs.: 18-20 and 23-25), and the second antiparvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A (i.e., comprises SEQ ID NOs.:8-10 and 13-15); (b) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A, and the second anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A (i.e., comprises SEQ ID NOs.:28-30 and 33-35);

(c) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A (i.e., comprises SEQ ID NOs.: 17 and 22), and the second anti -parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18 (i.e., comprises SEQ ID NOs.:7 and 12), as shown in Table A; or

(iv) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A, and the second antiparvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A (z.e., comprises SEQ ID NOs.:27 and 32).

Embodiment 68. A method for in vitro diagnosis of a parvovirus infection, the method comprising:

(i) contacting a sample from a subject with an anti-parvovirus antibody or antigen-binding fragment of any one of Embodiments 1-44; and

(ii) detecting a complex comprising an antigen and the anti-parvovirus antibody, or comprising an antigen and the anti-parvovirus antigen-binding fragment.

Embodiment 69. The method of any one of Embodiments 60-65 and 68 or the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, human B cell, and/or composition for use of Embodiment 66 or 67, wherein the parvovirus infection comprises a B19 infection and/or comprises a chronic parvovirus infection. TABLE 1. TABLE OF CERTAIN SEQUENCESAND SEQ ID NUMBERS

EXAMPLES

EXAMPLE 1

SELECTION AND ISOLATION OF B19-SPECIFIC MONOCLONAL ANTIBODIES

Supernatants from stimulated B cells from 30 healthy donor tonsils were screened for the presence of IgG binding to Parvovirus B19 VPl/VP2-expressing viruslike particles (VLPs) using an antigen-specific B-cell memory repertoire analysis (AMBRA) method (Figure 1). Half of the donors are positive to VP1/VP2. Forty-three percent (43%) of the tonsil donors scored positive. Three tonsils were selected for isolation of mAbs. IgG⁺ memory B cells from the three selected cryopreserved tonsils were immortalized with EBV and TLR agonist as described (Traggiai et al., Nat Med 2004, the techniques of which are incorporated herein by reference), and interrogated for the presence of antibodies against VLPs displaying VP1/VP2 or VP2 alone (native conformation ofVPl and VP2).

EXAMPLE 2

IMMUNODOMINANCE STUDY

An immunodominance study was conducted in AMBRA supernatants and different collections of sera. Figure 2A shows frequency of positivity from AMBRA supernatants on VP1/VP2 and VP2 VLPs. Figures 2B-2C show endpoint VP 1 vs VP2 from 60 Sera collected in Bologna, Italy (Figure 2B) or 111 sera collected in Bellinzona, Switzerland (Figure 2C): Ab values were expressed as endpoint titers defined as the highest dilution at which the OD was higher than twice the background OD. Figure 2D shows inhibition of competition in sera collected in Bellinzona with PAB5 (VP1) biotinylated vs PAB18 (VP2) biotinylated.

Additional data is provided in Figures 11 and 12. Ninety-six half area wellplates (Corning, 3690) were coated for 3 hours at 37 C with 25 pl of VP2-only or VP1- VP2 VLPs in PBS at 2 pg/ml (prospecbio.com/parvovirus_bl9_vlp_vpl-vp2). Plates were then blocked with PBS 1% BSA (Sigma-Aldrich, A3059) ON at 4C. After washing of the plates once with PBS 0.05% Tween 20 (PBS-T) (Sigma-Aldrich, 93773), plates were incubated with sera serially diluted (starting from 1 :50, 1 :3, 6 dilutions) for 1.5 h at RT. After 4 washing steps with PBS-T, goat anti-IgG alkalin phosphatase (Southern Biotech, 2040-04) diluted 1 :500 in PBS 1% BSA (Sigma- Aldrich, A3059) was added and incubated for 1 h at RT. Plates were then washed four times with PBS-T and 4-nitrophenyl phosphate (pNPP, Sigma-Aldrich, 71768) substrate was added. After 30 min incubation, absorbance at 405 nm was measured by a plate reader (Biotek) and data were plotted using Prism GraphPad 9.1.0. Data are shown in Figure 11. In another experiment (AMBRA analysis of B cell repertoire), ninety-six half area well-plates (Corning, 3690) were coated overnight at 4°C with 25 pl of VP2- only or VP1-VP2 VLPs in PBS at 1.5 pg/ml (prospecbio.com/parvovirus_bl9_vlp_vpl- vp2). After washing of the plates twice with PBS 0.05% Tween 20 (PBS-T) (Sigma- Aldrich, 93773), plates were blocked with PBS 2% BSA (Sigma-Aldrich, A3059) for 1 hour at RT. After washing of the plates twice with PBS-T, plates were incubated with AMBRA' s supernatants from different tonsils diluted 1 :4 in PBS 2% BSA for 1.5 h at RT.

After 4 washing steps with PBS-T, goat anti-IgG alkalin phosphatase (Southern Biotech, 2040-04) diluted 1 :500 in PBS 1

2% BSA was added and incubated for 1 h at RT. Plates were then washed four times with PBS-T and 4-nitrophenyl phosphate (pNPP, Sigma-Aldrich, 71768) substrate was added. After 30 min incubation, absorbance at 405 nm was measured by a plate reader (Biotek) and data were plotted using Prism GraphPad 9.1.0. Data are shown in Figure 12.

EXAMPLE 3

CHARACTERIZATION OF ANTI-PARVOVIRUS MONOCLONAL ANTIBODIES

Figure 3A provides a table showing, for the indicated mAbs (PAB5-PAC69), neutralization of mAb, the light chain isotype of mAb determined by ELISA, the germline usage for V-D-J (VH) and V-J (VL) genes defined using the ImMunoGeneTics information system (IMGT) database, and results of Western blot binding to reduced and non-reduced antigen.

Binding of various mAbs isolated from immortalized IgG+ memory B cells was assessed by ELISA (Figures 3B-3D). Binding to VP1/VP2 VLPs or VP2-only VLPs was used to determine the specificity of isolated mAbs so that VP 1 -specific mAbs bound to VP1/VP2 VLPs only, while VP2-specific mAbs bound to both VP1/VP2 VLPs and VP2 VLPs. Six anti-VPl and nine anti-VP2 mAbs were selected from the interrogation of memory IgG B cells derived from selected tonsils. Six mAbs were found to bind specifically to VP1 on VP1/VP2 VLPs. Nine mAbs were found to bind to VP2 on both VP1/VP2 VLPs (not shown) and to VP2 VLPs. MAbs bound with varying EC50s (as a proxy for binding avidity). Positive cultures were expanded and the VH and VL sequences were retrieved by RT-PCR to produce recombinant human IgGl .

Ninety-six half area well-plates (Corning, 3690) were coated overnight at 4 C with 25 pl of VP2-only or VP1/VP2 VLPs were coated in PBS at 1 pg/ml (prospecbio.com/parvovirus_bl9_vlp_vpl-vp2) in PBS pH 7.2. Plates were then blocked with PBS 1% BSA (Sigma-Aldrich, A3059) and subsequently incubated with mAb serial dilutions for 1 h at room temperature. After 4 washing steps with PBS 0.05% Tween 20 (PBS-T) (Sigma-Aldrich, 93773), goat anti-human IgG secondary antibody (Southern Biotech, 2040-04) was added and incubated for 1 h at room temperature. Plates were then washed four times with PBS-T and 4-nitrophenyl phosphate (pNPP, Sigma-Aldrich, 71768) substrate was added. After 30 min incubation, absorbance at 405 nm was measured by a plate reader (Biotek) and data were plotted using Prism GraphPad 9.1.0.

Figure 3B shows mAbs binding exclusively to VP1/VP2 VLPs (z.e., VP1- specific) (PAC24=PAC24.1 is not recombinant). Figure 3C shows mAbs binding to VP1/VP2 and VP2 VLPs (i.e., VP2-specific) (PAC57, PAC58, PAC59 are not recombinant). Figure 3D shows IgG and Fab of PAB5 mAb binding to VP1/VP2 VLPs.

Binding and blockade of binding (BOB) for IVIG (Grifols Pharmaceuticals), PAB5 and PAB18 mabs to VP1/VP2 VLPs were also compared. Figure 4A shows binding of IVIG, PAB5 and PAB18 mAbs to uVPl/VP2 VLPs by ELISA. Blockade of binding of labeled PAB5 (Figure 4B) or PAB18 (Figure 4C) mAbs to VP1/VP2 VLPs by different concentrations of unlabeled PAB5, PAB18, and IVIG was assessed.

EXAMPLE 4

NEUTRALIZATION OF B19 BY SELECTED MONOCLONAL ANTIBODIES

Identified anti- VP 1 and anti-VP2 IgGs were tested in neutralization assays using seronegative patient sera from primary B19 infections containing B 19 on UT7/Epo-Sl cells. After 3 days, the level of neutralization was measured by immunofluorescence analysis after permeabilization using a 488DL-anti-B19. Data on EPC primary cells showed potent neutralization by the selected VP1 and VP2 antibodies (Figures 6A-6C). Fc-mediated neutralization was exhibited by PAA19 and partially by PAB5, but not by PAB18.

EXAMPLE 5

CROSS-COMPETITION STUDIES AND EPITOPE MAPPING

Competition studies were performed to determine the spatial proximity of each of the epitopes recognized by the selected VP1- and VP2-specific mAbs. Results of the cross-competition studies were used to cluster the 6+9 (VP1 vs VP2 mAbs) tested mAbs into sub-groups.

Four uVPl antigenic sites (VP1-I to VP1-IV) were defined using the 6 VP1- specific mAbs: PAB5 and PAC21 were assigned to the VP1-I site, PAB47, PAC4 and PAC10 to VP1-II, VP1-III and VP1-IV, respectively (Figure 5A). Two VP2 antigenic sites were defined with the 9 VP2-specific mAbs tested. PAB18, PAA21, PAA23 and PAC60 mAbs were assigned to the VP2-I antigenic site, while PAA19 was assigned to a unique VP2-II antigenic site due to the lack of competition with VP2-I mAbs such as PAB18 and PAC60. PAC40, PAC58 and PAC57 were assigned to a site overlapping VP2-I and VP2-II (VP2-I/II). PAC69 mAb was not assigned to a specific site due to the observed pattern of competition with PAC40 and PAC58 mAbs but not with the other VP1-I site mAbs (Figure 5B).

MAbs were labeled with biotin and tested by ELISA in a matrix competition assay, in which unlabeled antibodies were incubated first at a concentration of 5 pg/ml on VP2- or VP1/VP2 VLPs coated plates (coating in PBS at 2 pg/ml), followed by the addition of a limiting concentration of biotinylated antibodies whose binding was revealed with alkaline phosphatase-conjugated streptavidin. When interpreting competition results, it should be taken into account that if two epitopes overlap, or the areas covered by the arms of the two antibodies overlap, competition should be almost complete. Weak inhibitory or enhancing effects may reflect a decrease in affinity owing to steric or allosteric effects.

Epitope specificity on a selection of VP 1 -specific antibodies was determined using a library of cyclic peptides. Figure 5C shows an intensity plot with averaged spot intensities of PAB5-rIgGl (lOpg/ml) on a conformational peptide microarray containing 696 different cyclic constrained peptides. Figure 5D shows an intensity plot with averaged spot intensities of PAA19-rIgGl (500 pg/ml) on a conformational peptide microarray containing 1,677 different cyclic constrained peptides. The intensity plots were correlated with peptide and intensity maps as well as with visual inspection of the microarray scans to identify the epitopes of the human antibodies. In case it was not clear if a certain amino acid contributed to antibody binding, the corresponding letter was written in lighter font.

PAB5 binds to the TGTDLE (SEQ ID NO.:4) peptide (highly conserved) in the RBD of VP1. Analysis of public databases was performed (n=280), and four variants were identified as potential escapes (TETDLE) (SEQ ID NO.:43).

Figure 5E shows an amino acid plot of PAB5-rIgGl against the microarray containing conformational peptides with 119 variants of the wild type peptide: the plot was calculated by dividing the spot intensity of a given peptide (e.g.,¹YPYDVQDYA⁹) (SEQ ID NO.:44) by the spot intensity of the native epitope (¹YPYDVPDYA⁹) (SEQ ID NO.:45). The position of an amino acid at a given position, thus, reflects the intensity ratio compared to the wild type amino acid at the same position. The heat map highlights a conserved core motif²GTDLE⁶ (SEQ ID NO.:46). Amino acid positions³T,⁴D and⁶E were essential for binding by PAB5, as all amino acid changes were not tolerated. Positions²G and⁵L display only a very limited tolerance for substitutions. The N- and C-terminal amino acid positions ’T and⁷L are less essential for binding.

The VP1 RBD (5-80 aa) includes a rigid fold of three alpha helices (with conserved aa). The peptide TGTDLE (SEQ ID NO. :4) is in the loop region between helix 1 and helix 2. Mutation on TGTDLE (SEQ ID NO.:4) changes the spatial assembly of the three helices. Analysis of all permutations of the epitope was performed (Figure 7).

EXAMPLE 6 ADDITIONAL STUDIES

Neutralization of infection was assessed using flow cytometry. Briefly, aliquots of infected EPCs collected at 72 hpi were analyzed using flow cytometry (FACSCalibur, Becton Dickinson) to determine the percentage of VP proteins- positive cells. Aliquots of 5 x 10⁵ EPCs were fixed in PBS-paraformaldehyde 0.5% at 4°C overnight and permeabilised in PBS containing 0.2% Saponin. After 45 min at room temperature, the cells were washed with PBS and resuspended in 50 pl monoclonal mouse antibody against VP1 and VP2 proteins (MAB8293, Merck), diluted 1 :200 in PBS/FCS 2%, for 1 h at room temperature. After washing in PBS, cells were incubated for 1 h with AlexaFluor488 anti-mouse secondary antibody, diluted 1 : 1000 in PBS/ FCS 2%. Data were analyzed using the Cell Quest Pro Software (Becton Dickinson). % Neutralization was calculated using the value of % FITC positive cell without antibody as 0% and the value of % FITC positive cell with the highest amount of PAB5+PAA19 combo as 100%. Figure 9A shows neutralization obtained from an experiment performed with titration of the antibodies or combo. Figure 9B shows neutralization obtained from an experiment with further titrations of the antibodies or combo. Figure 9C shows neutralization obtained from an experiment with 1 ug/ml of antibody or combo. Neutralization of infection was also assessed via nucleic acid analysis. Briefly, equal amounts of 1 xlO⁵ cells were collected at 2 and 72 hpi following infection and processed by using the Maxwell Viral Total Nucleic Acid kit on a Maxwell MDx platform (Promega), to obtain a total nucleic acid fraction in elution volumes of 100 pL. For quantitative analysis of viral DNA, an aliquot of the eluted nucleic acids, corresponding to 500 cells, was amplified by qPCR (Maxima SYBR Green qPCR Master Mix, Thermo Scientific) in a RotorQ system (Qiagen). For the analysis of B 19V RNA, parallel aliquots were first treated with the Turbo DNAfree reagent (Ambion) before amplification in a qRT-PCR assay (QuantiNova SYBR Green RT-PCR Kit, Qiagen). The primer pair R2210-R2355, located in the central exon of B19V genome, was used to amplify both viral DNA and total RNA. Quantitation of viral DNA and RNA was obtained by the absolute quantitation algorithm, converting quantification cycle (Cq) values to geq number using external calibration curves obtained from standard targets. Finally, from the B19V DNA values, the IC80 value was calculated through interpolation and data are reported from 2 independent experiments (Figure 10A) or from 3 independent experiments (Figure 10B).

The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, including U.S. Patent Application No. 63/352,600, filed on June 15, 2022, are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments.

These and other changes can be made to the embodiments in light of the above- detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

Claims

CLAIMS What is claimed is:

1. An anti -parvovirus antibody, or an antigen-binding fragment thereof.

2. The anti-parvovirus antibody or antigen-binding fragment of claim 1, wherein the parvovirus comprises an erythrovirus, wherein, optionally, the parvovirus is an erythrovirus.

3. The anti-parvovirus antibody or antigen-binding fragment of claim 1 or 2, wherein the parvovirus comprises Bl 9, wherein, optionally, the parvovirus is Bl 9.

4. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, which binds to an epitope in B19 uVPl.

5. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-4, which binds to a peptide having the amino acid sequence TGTDLE (SEQ ID N0.:4).

6. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-4, which binds to a peptide having the amino acid sequence X1X2TDX3EX4 (SEQ ID NO.:5), wherein:

Xi is present or absent, and, if present, is any amino acid;

X2 is G or F, and is preferably G;

X3 is L or K, and is preferably K; and

X4 is present or absent, and, if present, is any amino acid except P.

7. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-6, comprising: (i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and/or

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

8. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-7, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)Hl, the CDRH2, and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.: 17; and

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:22, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

9. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-7, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.:20, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.:25, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

10. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-7 and 9, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.: 18, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.: 19, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.:23, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.:24, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

11. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-10, comprising the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.: 18-20 and 23-25, respectively.

12. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-11, comprising:

(i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 17; and/or

(ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or consisting of, the amino acid sequence set forth in SEQ ID NO.:22.

13. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-12, comprising:

(i) a heavy chain variable domain (VH) comprising the amino acid sequence set forth in SEQ ID NO.: 17; and

(ii) a light chain variable domain (VL) comprising the amino acid sequence set forth in SEQ ID NO.:22.

14. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, which binds to an epitope in B19 VP2.

15. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3 and 14, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:7; and/or

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO. : 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

16. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, and 15, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)Hl, the CDRH2, and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:7; and

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO. : 12, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia,

North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

17. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3 and 14-15, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.: 10, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.: 15, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

18. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, 15, and 17, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.:8, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.:9, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.: 13, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.: 14, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

19. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3 and 14-18, comprising the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.:8-10 and 13-15, respectively.

20. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3 and 14-19, comprising:

(i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or consisting of, the amino acid sequence set forth in SEQ ID NO.:7; and/or

(ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or consisting of, the amino acid sequence set forth in SEQ ID NO.: 12.

21. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3 and 14-20, comprising:

(i) a heavy chain variable domain (VH) comprising the amino acid sequence set forth in SEQ ID NO.:7; and

(ii) a light chain variable domain (VL) comprising the amino acid sequence set forth in SEQ ID NO.: 12.

22. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3 and 14, comprising:

(i) in a heavy chain variable domain (VH), the complementarity determining region (CDR)H1, the CDRH2, and/or the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and/or

(ii) in a light chain variable domain (VL), the CDRL1, the CDRL2, and/or the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia,

North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

23. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, and 22, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)Hl, the CDRH2, and the CDRH3 of the VH amino acid sequence set forth in SEQ ID NO.:27; and

(ii) in a/the light chain variable domain (VL), the CDRL1, the CDRL2, and the CDRL3 of the VL amino acid sequence set forth in SEQ ID NO.:32, wherein the CDRs are defined in accordance with the IMGT, Kabat, Chothia, North, EU, Martin (Enhanced Chothia), Contact, or AHo numbering system, or in accordance with any combination thereof.

24. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, and 22, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H3 amino acid sequence set forth in SEQ ID NO.:30, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions;

(ii) in a/the light chain variable domain (VL), the complementarity determining region (CDR)L3 amino acid sequence set forth in SEQ ID NO.:35, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

25. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, 22, and 24, comprising:

(i) in a/the heavy chain variable domain (VH), the complementarity determining region (CDR)H1 amino acid sequence set forth in SEQ ID NO.:28, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the complementarity determining region (CDR)H2 amino acid sequence set forth in SEQ ID NO.:29, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions; and

(ii) in a/the light chain variable domain (VL), the CDRL1 amino acid sequence set forth in SEQ ID NO.:33, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions, and the CDRL2 amino acid sequence set forth in SEQ ID NO.:34, or a functional variant thereof comprising one, two, or three, optionally conservative, amino acid substitutions.

26. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, and 22-25, comprising the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 amino acid sequences set forth in SEQ ID NOs.:28-30 and 33-35, respectively.

27. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, and 22-26 comprising:

(i) a heavy chain variable domain (VH) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or consisting of, the amino acid sequence set forth in SEQ ID NO.:27; and/or

(ii) a light chain variable domain (VL) comprising an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identity to, or consisting of, the amino acid sequence set forth in SEQ ID NO.:32.

28. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-3, 14, and 22-27, comprising: (i) a heavy chain variable domain (VH) comprising the amino acid sequence set forth in SEQ ID NO.:27; and

(ii) a light chain variable domain (VL) comprising the amino acid sequence set forth in SEQ ID NO.:32.

29. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-28, wherein the anti -parvovirus antibody or antigen-binding fragment comprises a human antibody, a monoclonal antibody, a purified antibody, a single chain antibody, a Fab, a Fab’, a F(ab’)2, or Fv.

30. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-29, wherein the anti -parvovirus antibody or antigen-binding fragment is a multi-specific antibody or antigen-binding fragment, wherein, optionally, the antibody or antigen-binding fragment is a bi-specific antibody or antigen-binding fragment.

31. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-30, wherein the anti -parvovirus antibody or antigen-binding fragment comprises an (e.g., IgGl) Fc polypeptide or a fragment thereof.

32. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-31, which comprises an IgG, IgA, IgM, IgE, or IgD isotype.

33. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-32, which comprises an IgG isotype selected from IgGl, IgG2, IgG3, and IgG4.

34. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-33, which comprises an IgGl isotype.

35. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-34, which comprises an IgGlm3 allotype, an IgGlml7 allotype, an IgGlml allotype, or any combination thereof.

36. The anti-parvovirus antibody or antigen-binding fragment of claim 31- 35, wherein the Fc polypeptide or fragment thereof comprises:

(i) a mutation that increases binding affinity to a human FcRn (e.g., as measured using surface plasmon resonance (SPR) (e.g., Biacore, e.g., T200 instrument, using manufacturer’s protocols)), as compared to a reference Fc polypeptide that does not comprise the mutation; and/or

(ii) a mutation that increases binding affinity to a human FcyR (e.g., as measured using surface plasmon resonance (SPR) (e.g., Biacore, e.g., T200 instrument, using manufacturer’s protocols, and/or as measured using mesoscale discovery (MSD))) as compared to a reference Fc polypeptide that does not comprise the mutation.

37. The anti-parvovirus antibody or antigen-binding fragment of claim 36, wherein the mutation that increases binding affinity to a human FcRn comprises: M428L; N434S; N434H; N434A; N434S; M252Y; S254T; T256E; T250Q; P257I; Q311I; D376V; T307A; E380A; or any combination thereof.

38. The anti-parvovirus antibody or antigen-binding fragment of claim 36 or 37, wherein the mutation that increases binding affinity to a human FcRn comprises: (i) M428L/N434S; (ii) M252Y/S254T/T256E; (iii) T250Q/M428L; (iv) P257I/Q311I; (v) P257I/N434H; (vi) D376V/N434H; (vii) T307A/E380A/N434A; (viii) M428L/N434A; or (ix) any combination of (i)-(viii).

39. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 36-38, wherein the mutation that increases binding affinity to a human FcRn comprises M428L/N434S or M428L/N434A.

40. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 36-38, wherein the mutation that enhances binding to a FcyR comprises S239D; I332E; A330L; G236A; or any combination thereof.

41. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 36-40, wherein the mutation that enhances binding to a FcyR comprises: (i) S239D/I332E; (ii) S239D/A330L/I332E; (iii) G236A/S239D/I332E; or (iv) G236A/A330L/I332E, wherein the Fc polypeptide or fragment thereof optionally comprises Ser at position 239.

42. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-41, which comprises a mutation that alters glycosylation, wherein the mutation that alters glycosylation comprises N297A, N297Q, or N297G, and/or which is aglycosylated, and/or which is afucosylated.

43. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-42, which: is afucosylated; has been produced in a host cell that is incapable of fucosylation or that is inhibited in its ability to fucosylate a polypeptide; has been produced under conditions that inhibit fucosylation thereof by a host cell; or any combination thereof.

44. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-43, which is human, humanized, or chimeric.

45. An isolated polynucleotide encoding the anti -parvovirus antibody or antigen-binding fragment of any one of claims 1-44, or encoding a VH, a heavy chain, a VL, and/or a light chain of the anti-parvovirus antibody or the antigen-binding fragment.

46. The polynucleotide of claim 45, wherein the polynucleotide comprises deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), wherein the RNA optionally comprises messenger RNA (mRNA).

47. The polynucleotide of any one of claims 45-46, comprising a modified nucleoside, a cap-1 structure, a cap-2 structure, or any combination thereof.

48. The polynucleotide of claim 47, wherein the polynucleotide comprises a pseudouridine, a N6-methyladenonsine, a 5-methylcytidine, a 2-thiouridine, or any combination thereof.

49. The polynucleotide of claim 48, wherein the pseudouridine comprises N 1 -methylpseudouridine.

50. The polynucleotide of any one of claims 45-49, which is codon- optimized for expression in a host cell.

51. The polynucleotide of claim 50, wherein the host cell comprises a human cell.

52. A recombinant vector comprising the polynucleotide of any one of claims 45-51.

53. A host cell comprising the polynucleotide of any one of claims 45-51 and/or the vector of claim 52, wherein the polynucleotide is optionally heterologous to the host cell and/or wherein the host cell is capable of expressing the encoded antibody or antigen-binding fragment or polypeptide.

54. An isolated human B cell comprising the polynucleotide of any one of claims 45-51 and/or the vector of claim 52, wherein polynucleotide is optionally heterologous to the human B cell and/or wherein the human B cell is immortalized.

55. A composition comprising:

(i) the anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-44;

(ii) the polynucleotide of any one of claims 45-51;

(iii) the recombinant vector of claim 52;

(iv) the host cell of claim 53; and/or

(v) the human B cell of claim 54, and a pharmaceutically acceptable excipient, carrier, or diluent.

56. The composition of claim 55, comprising a first anti-parvovirus antibody or antigen-binding fragment and a second anti-parvovirus antibody or antigen-binding fragment, wherein each of the first antibody or antigen-binding fragment and the second antibody or antigen-binding fragment are different and are each according any one of claims 1-44, wherein, preferably, the first anti -parvovirus antibody or antigen-binding fragment binds to an epitope in B19 uVPl and the second anti -parvovirus antibody or antigen-binding fragment binds to an epitope in B19 VP2, wherein, optionally:

(i) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A, and the second anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB18, as shown in Table A;

(ii) the first anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAB5, as shown in Table A, and the second anti-parvovirus antibody or antigen-binding fragment comprises the CDRH1, CDRH2, CDRH3, CDRL1, CDRL2, and CDRL3 of antibody PAA19, as shown in Table A; (iii) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A, and the second antiparvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB18, as shown in Table A; or

(iv) the first anti-parvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAB5, as shown in Table A, and the second antiparvovirus antibody or antigen-binding fragment comprises the VH and the VL of antibody PAA19, as shown in Table A.

57. A composition comprising the polynucleotide of any one of claims 45-51 or the vector of claim 52 encapsulated in a carrier molecule, wherein the carrier molecule optionally comprises a lipid, a lipid-derived delivery vehicle, such as a liposome, a solid lipid nanoparticle, an oily suspension, a submicron lipid emulsion, a lipid microbubble, an inverse lipid micelle, a cochlear liposome, a lipid microtubule, a lipid microcylinder, lipid nanoparticle (LNP), or a nanoscale platform.

58. A method of making an anti -parvovirus antibody or antigen-binding fragment of any one of claims 1-44, comprising culturing the host cell of claim 53 or the human B cell of claim 54 for a time and under conditions sufficient for the host cell or human B cell, respectively, to express the anti-parvovirus antibody or antigenbinding fragment.

59. The method of claim 58, further comprising isolating the anti-parvovirus antibody or antigen-binding fragment.

60. A method of treating or preventing a parvovirus infection in a subject, the method comprising administering to the subject an effective amount of

(i) the anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-44; (ii) the polynucleotide of any one of claims 45-51, wherein, optionally, the polynucleotide comprises mRNA;

(iii) the recombinant vector of claim 52;

(iv) the host cell of claim 53;

(v) the human B cell of claim 54; and/or

(vi) the composition of any one of claims 55-57.

61. The method of claim 60, comprising administering a single dose of the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, or composition to the subject.

62. The method of claim 60 or 61, comprising administering two or more doses of the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, or composition to the subject.

63. The method of any one of claims 60-62, comprising administering the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, or composition intramuscularly, subcutaneously, or intravenously.

64. The method of any one of claims 60-63, wherein the treatment and/or prevention comprises post-exposure prophylaxis.

65. The method of any one of claims 60-64, wherein the subject has received, is receiving, or will receive an antiviral.

66. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-44, the polynucleotide of any one of claims 45-51, the recombinant vector of claim 52, the host cell of claim 53, the human B cell of claim 54, and/or the composition of any one of claims 55-57, for use in a method of treating or preventing a parvovirus infection in a subject.

67. The anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-44, the polynucleotide of any one of claims 45-51, the recombinant vector of claim 52, the host cell of claim 53, the human B cell of claim 54, and/or the composition of any one of claims 55-57, for use in the preparation of a medicament for the treatment or prevention of a parvovirus infection in a subject.

68. A method for in vitro diagnosis of a parvovirus infection, the method comprising:

(i) contacting a sample from a subject with an anti-parvovirus antibody or antigen-binding fragment of any one of claims 1-44; and

(ii) detecting a complex comprising an antigen and the anti-parvovirus antibody, or comprising an antigen and the anti-parvovirus antigen-binding fragment.

69. The method of any one of claims 60-65 and 68 or the anti-parvovirus antibody or antigen-binding fragment, polynucleotide, recombinant vector, host cell, human B cell, and/or composition for use of claim 66 or 67, wherein the parvovirus infection comprises a B19 infection and/or comprises a chronic parvovirus infection.