US20190134196A1

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Publication number: US20190134196A1
Application number: US16/305,828
Authority: US
Inventors: Cheng Zhang; Kesuo Fan; Yong Guo; Chenjiang YAO; Hua Zhang; Xiaofeng Wang; Shuqian Jing
Original assignee: Gmax Biopharm LLC
Current assignee: Gmax Biopharm LLC
Priority date: 2016-05-31
Filing date: 2017-05-27
Publication date: 2019-05-09
Also published as: EP3476864A4; KR20190013918A; US20230346932A1; JP7090557B2; WO2017206840A1; CA3025714A1; KR102549008B1; TWI826351B; KR20230098919A; AU2017273959A1; JP2019523764A; KR102669444B1; AU2017273959B2; TW201805023A; EP3476864A1

Abstract

Provided herein are a stable solution formulation of an ET_AR antibody, and use thereof in treating, preventing, or alleviating one or more symptoms of pulmonary arterial hypertension or one or more symptoms of cancer of a reproductive organ.

Description

FIELD

Provided herein are an ET_AR antibody and a pharmaceutical composition thereof, for example, a stable pharmaceutical solution formulation of the ET_AR antibody. Also provided herein is a method of treating, preventing, or alleviating one or more symptoms of pulmonary arterial hypertension or one or more symptoms of cancer of a reproductive organ.

BACKGROUND

Endothelin (ET) is a vasoconstriction peptide hormone, important to the homeostasis and regulation of the biological functions of the cardiovascular system. ET is found not only in the endothelium but also in many other tissues and cell types (Barton et al., 2008, Can. J. Physiol. Pharmacol.86:485-498). ET is a 2,400 Da peptide of 21 amino acids, having 2 disulfide bonds at its N-terminus, linking the 1st and 15th cysteine residues and the 3rd and 11th cysteine residues, respectively. Its C-terminus contains hydrophobic amino acid residues. Its N-terminal structure is important for binding to its receptor, while its C-terminal structure is important as to where on the receptor to bind. ET has three isoforms: ET-1, ET-2 and ET-3. They differ by a few amino acid residues. ET-1 plays a major role in the regulation of the biological functions of the cardiovascular system. Upon stimulation, endothelial cells synthesize and release ET-1. ET-1 is mainly regulated at the transcription level.

Endothelin receptors (ETR) has two isoforms: ET_AR and ETBR, which belong to the G protein-coupled receptor (GPCR) family. Upon stimulation, ET_AR activates membrane Na⁺/Ca²⁺ exchanger (NCX) and Na⁺/H⁺ exchanger (NHE) to increase cellular Ca²⁺ concentrations and to sensitize muscle fibers to Ca²⁺, resulting in the constriction of vascular smooth muscle and cardiac muscle (Neylon, 1999, Clin. Exp. Pharmacol. Physiol.26:149-153). Unlike ET_AR, ETBR mainly relaxes the vascular smooth muscle cells and cardiac muscle cells (Nelson et al., 2003, Nat. Rev. Cancer3:110-113).

ET_AR belongs to GPCR family A and has seven transmembrane domains. The extracellular domain is short and small, and only accounts for about one seventh of the full-length receptor, while a GPCR antibody can only target its extracellular domain.

Therefore, the structural feature and naturally low expression level of a GPCR make it difficult to produce biologically active antigens.

Pulmonary arterial hypertension (PAH) is due to the vasoconstriction of the lung or lung related vasculature, resulting in lung artery insufficiency and a compensatory increase in the blood pressure of the heart. On the microscopic scale, there appear to be changes in the small pulmonary arteries, including intimal fibrosis, medial hypertrophy, and plexiform lesions, causing in situ thrombosis of elastic and small pulmonary arteries, and resulting in increased blood circulation resistance in the whole lung vasculature (Simonneau et al., 2004, J. Am. Coll. Cardiol.43:5S-12S; Barst et al., 2004, J. Am. Coll. Cardiol.43:40S-47S). PAH is a disease with a fairly high rate of disability or death. It is a devastating disease that severely affects the health of patients and imposes significant burden on society.

The severity of PAH depends on the degree of relevant cardiac deformity, and the common congenital cardiac abnormalities that will result in secondary PAH includes: aortic stenosis, aortopulmonary window, atrial septal defect, complete atrioventricular septal defect, artery coarctation, dilated cardiomyopathy, double outlet right ventricle, hypertrophic cardiomyopathy, mitral stenosis, patent ductus arteriosus, single ventricle, persistent truncus arteriosus, and ventricular septal defect. PAH mainly affects pulmonary arteries and right heart, causing right ventricular hypertrophy, right atrial dilatation, the dilatation of the trunk of the pulmonary artery, and the sparsity of the surrounding pulmonary arterioles. The hypertrophy of endothelial and smooth muscle cells of pulmonary arteriole results in tunica intima fibrosis, tunica media hypertrophy, lumina stenosis, occlusion or distortion, and plexus change. Tunica intima fibrosis and lumina occlusion may also afflict the pulmonary venules.

It has been shown that an ET_AR antagonist can effectively block the increase in vascular pressure caused by endothelin to ameliorate PAH symptoms and improve exercise capability and hemodynamics in PAH patients (Serasli et al., 2010, Recent Pat. Cardiovasc. Drug Discov.5:184-95). The antibody provided herein can specifically bind to a human ET_AR and attenuate pulmonary arterial pressure in an animal model. It can significantly improve a symptom of PAH in an animal model.

SUMMARY

The ET_AR antibody provided herein comprises 1, 2, 3, 4, 5, or 6 amino acid sequences, wherein each amino acid sequence is independently selected from:

- a. light chain CDR1 amino acid sequences: SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 28, and SEQ ID NO: 30;
- b. light chain CDR2 amino acid sequences: SEQ ID NO: 32, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 38, SEQ ID NO: 40, SEQ ID NO: 42, SEQ ID NO: 44, SEQ ID NO: 46, and SEQ ID NO: 48;
- c. light chain CDR3 amino acid sequences: SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 54, SEQ ID NO: 56, SEQ ID NO: 58, SEQ ID NO: 60, SEQ ID NO: 62, SEQ ID NO: 64, SEQ ID NO: 66, and SEQ ID NO: 68;
- d. heavy chain CDR1 amino acid sequences: SEQ ID NO: 70, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 76, SEQ ID NO: 78, SEQ ID NO: 80, SEQ ID NO: 82, SEQ ID NO: 84, SEQ ID NO: 86, SEQ ID NO: 88, and SEQ ID NO: 90;
- e. heavy chain CDR2 amino acid sequences: SEQ ID NO: 92, SEQ ID NO: 94, SEQ ID NO: 96, SEQ ID NO: 98, SEQ ID NO: 100, SEQ ID NO: 102, SEQ ID NO: 104, SEQ ID NO: 106, SEQ ID NO: 108, SEQ ID NO: 110, SEQ ID NO: 112, and SEQ ID NO: 114; and
- f. heavy chain CDR3 amino acid sequences: SEQ ID NO: 116, SEQ ID NO: 118, SEQ ID NO: 120, SEQ ID NO: 122, SEQ ID NO: 124, SEQ ID NO: 126, SEQ ID NO: 128, SEQ ID NO: 130, SEQ ID NO: 132, SEQ ID NO: 134, and SEQ ID NO: 136.

Also provided herein is a pharmaceutical composition comprising an ET_AR antibody provided herein and one or more pharmaceutically acceptable carriers.

Provided herein is a stable pharmaceutical solution formulation of an ET_AR antibody, comprising an ET_AR antibody provided herein and a buffer.

Provided herein is a method of treating, preventing or alleviating one or more symptoms of pulmonary arterial hypertension in a subject, comprising administrating to the subject a therapeutically effective amount of a pharmaceutical composition provided herein, for example, a stable pharmaceutical solution formulation of an ET_AR antibody provided herein.

Provided herein is a method of treating, preventing, or alleviating one or more symptoms of a disease associated with elevated pulmonary arterial pressure in a subject, comprising administrating to the subject a therapeutically effective amount of a pharmaceutical composition provided herein, for example, a stable pharmaceutical solution formulation of an ET_AR antibody provided herein.

Provided herein is a method of treating, preventing, or alleviating one or more symptoms of cancer of a reproductive organ in a subject, comprising administrating to the subject a therapeutically effective amount of a pharmaceutical composition provided herein, for example, a stable pharmaceutical solution formulation of an ET_AR antibody provided herein.

Provided herein is a kit for treating pulmonary arterial hypertension, a disease associated with elevated pulmonary arterial pressure, or cancer of a reproductive organ, comprising a pharmaceutical composition provided herein.

Provided herein is use of a pharmaceutical composition provided herein in the manufacture of a medicament for treating pulmonary arterial hypertension, a disease associated with elevated pulmonary arterial pressure, or cancer of a reproductive organ.

Provided herein is an isolated nucleic acid comprising a polynucleotide sequence encoding an ET_AR antibody provided herein.

Provided herein is a recombinant expression vector comprising a nucleic acid provided herein.

Provided herein is a host cell comprising a vector provided herein.

Provided herein is a method for producing an ET_AR antibody, comprising cultivating a host cell under conditions suitable for expressing an antibody provided herein.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the ELISA screening results of the supernatants of hybridomas for binding to CHO-DHFR-ET_AR cells (labeled as CHO-ET_AR in the figure). Among them, the ET_AR antibody A-1 (comprising SEQ ID NO: 138 and SEQ ID NO: 166) was obtained from hybridoma clone 15F3.

FIG. 2 shows the specific binding of recombinant ET_AR antibodies (A-1, A-2 (comprising SEQ ID NO: 140 and SEQ ID NO: 168), A-7 (comprising SEQ ID NO: 150 and SEQ ID NO: 178), and A-12 (comprising SEQ ID NO: 160 and SEQ ID NO: 188)) to human ET_AR as determined by FACS. The gray peak and the dotted peak are negative controls, the dotted peak representing the binding curve of the ET_AR antibody to CHO-DHFR- and the solid line peak representing the binding curve of the ET_AR antibody to CHO-DHFR-ET_AR.

FIG. 3 shows the inhibitory effects of the supernatants of hybridomas on cellular ET_AR-mediated Ca²⁺ changes as determined using a calcium flux assay.

FIG. 4 shows the dose responses of recombinant ET_AR antibodies on the inhibition of human ET_AR as determined using a calcium flux assay (IC₅₀=37.91 nM, R²=0.97) (A-1); (IC₅₀=87.84 nM, R²=0.97) (A-9 (comprising SEQ ID NO: 154 and SEQ ID NO: 182)).

FIG. 5 shows the in vivo activity of the recombinant ET_AR (A-1) in a hypoxia-induced PAH cynomolgus monkey model. A-1 was found to be able to reduce the hypoxia-induced pulmonary systolic pressure significantly, and also to be effective within 96-hr as measured by area under the curve of the pulmonary systolic pressure versus time.

FIG. 6 shows that the biological activity of ET_AR antibody A-1 (25 mg/mL) did not change significantly after 3 months of storage in a formulation solution containing 20 mM sodium citrate, 140 mM arginine-HCl, and 0.04% TWEEN-80 at pH 5.8 and 4° C.

FIG. 7 shows that the biological activity of ET_AR antibody A-1 (25 mg/mL) did not change significantly after 3 months of storage in a formulation solution containing 20 mM sodium citrate, 140 mM arginine-HCl, and 0.04% TWEEN-80 at pH 5.8 and 25° C.

DETAILED DESCRIPTIONDefinitions

Unless otherwise defined herein, scientific and technical terms provided herein shall have the meanings that are commonly understood by those of ordinary skill in the art. Generally, nomenclatures and techniques provided herein in connection with pharmacology, biology, biochemistry, cell and tissue culture, molecular biology, immunology, microbiology, genetics and protein and nucleic acid chemistry and hybridization are those well-known and commonly used in the art.

The standard one- or three-letter abbreviations provided herein describe polynucleotide and polypeptide sequences. Unless otherwise specified, polypeptide sequences have their amino termini at the left and their carboxyl termini at the right, and single-stranded nucleic acid sequences and the top strands of double-stranded nucleic acid sequences have their 5′ termini at the left and their 3′ termini at the right. A particular section of a polypeptide can be designated by amino acid residue numbers such asamino acids 80 to 130, or in combination with the corresponding actual residues such as Lys80 to Lys130. A particular polypeptide or polynucleotide sequence also can be described by showing its differences from a reference sequence.

The terms “peptide” “polypeptide” and “protein” each refer to a molecule comprising two or more amino acid residues joined to each other by peptide bonds. These terms encompass, e.g., native and artificial proteins, protein fragments and polypeptide analogs (such as muteins, variants, and fusion proteins) of a protein sequence as well as post translationally, or otherwise covalently or non-covalently, modified proteins. A peptide, polypeptide, or protein may be monomeric or polymeric.

The term “polypeptide fragment” refers to a polypeptide that has an amino-terminal and/or carboxyl-terminal deletion as compared to a corresponding full-length protein. Fragments can be, for example, at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 50, 70, 80, 90, 100, 150 or 200 amino acids in length. Fragments can also be, for example, at most 1,000, 750, 500, 250, 200, 175, 150, 125, 100, 90, 80, 70, 60, 50, 40, 30, 20, 15, 14, 13, 12, 11, or 10 amino acids in length. A fragment can further comprise, at either or both of its ends, one or more additional amino acids, for example, a sequence of amino acids from a different naturally-occurring protein (e.g., an Fc or leucine zipper domain) or an artificial amino acid sequence (e.g., an artificial linker sequence).

Polypeptides of the disclosure include polypeptides that have been modified in any way and for any reason, for example, to: (1) reduce susceptibility to proteolysis, (2) reduce susceptibility to oxidation, (3) alter susceptibility to form a protein complex, (4) alter binding affinities, and (4) confer or modify other physicochemical or functional properties. Analogs include muteins of a polypeptide. For example, single or multiple amino acid substitutions (e.g., conservative amino acid substitutions) can be made in the naturally occurring sequence (e.g., in the portion of the polypeptide outside the domain(s) forming intermolecular contacts). A “conservative amino acid substitution” is one that does not substantially change the structural characteristics of the parent sequence (e.g., replacement of an amino acid should not break a helix that occurs in the parent sequence, or disrupt other types of secondary structure that characterize the parent sequence or are necessary for its functionality).

A “variant” of a polypeptide comprises an amino acid sequence wherein one or more amino acid residues are inserted into, deleted from and/or substituted into the amino acid sequence relative to another polypeptide sequence. Variants of the disclosure include fusion proteins.

A “derivative” of a polypeptide is a polypeptide that has been chemically modified, e.g., via conjugation to another chemical moiety such as, for example, polyethylene glycol, albumin (e.g., human serum albumin), phosphorylation, and glycosylation.

Unless otherwise indicated, the term “antibody” includes, in addition to antibodies comprising two full-length heavy chains and two full-length light chains, derivatives, variants, fragments, and muteins thereof, examples of which are described below.

An “antibody” is a protein comprising a portion that binds to an antigen and optionally a scaffold or framework portion that allows the antibody to adopt a conformation that promotes the binding of the antibody to the antigen. Examples of antibodies include antibodies, antibody fragments (e.g., an antigen binding portion of an antibody), antibody derivatives, and antibody analogs. The antibody can comprise, for example, an alternative protein scaffold or artificial scaffold with grafted CDRs or CDRs derivatives. Such scaffolds include, but are not limited to, antibody-derived scaffolds comprising mutations introduced, for example, to stabilize the three-dimensional structure of the antibody as well as completely synthetic scaffolds comprising, for example, a biocompatible polymer. See, for example, Korndorfer et al., 2003, Proteins: Structure, Function, and Bioinformatics,53:121-129; Roque et al., 2004, Biotechnol. Prog.20:639-654. In addition, peptide antibody mimetics (“PAMs”) can be used, as well as scaffolds based on antibody mimetics utilizing fibronectin components as a scaffold.

An antibody can have, for example, the structure of a naturally occurring immunoglobulin. An “immunoglobulin” is a tetrameric molecule. In a naturally occurring immunoglobulin, each tetramer is composed of two identical pairs of polypeptide chains, each pair having one “light” (about 25 kDa) and one “heavy” chain (about 50-70 kDa). The amino-terminal portion of each chain includes a variable region of about 100 to 110 or more amino acids primarily responsible for antigen recognition. The carboxyl terminal portion of each chain defines a constant region primarily responsible for effector function. Human light chains are classified as kappa and lambda light chains. Heavy chains are classified as mu, delta, gamma, alpha, or epsilon, and define the antibody's isotype as IgM, IgD, IgG, IgA, and IgE, respectively. Within light and heavy chains, the variable and constant regions are joined by a “J” region of about 12 or more amino acids. The heavy chain also includes a “D” region of about 10 more amino acids. See generally, Fundamental Immunology, Ch. 7 (Paul, W., ed., 2nd ed. Raven Press, N.Y. (1989)) (incorporated herein by reference in its entirety for all purposes). The variable regions of each light/heavy chain pair form the antibody binding site such that an intact immunoglobulin has two binding sites.

Naturally occurring immunoglobulin chains exhibit the same general structure of relatively conserved framework regions (FR) joined by three hypervariable regions, also called complementarity determining regions or CDRs. From N-terminus to C-terminus, both light and heavy chains comprise regions FR1, CDR1, FR2, CDR2, FR3, CDR3 and FR4. The assignment of amino acids to each region is in accordance with the definitions of Kabat et al. in Sequences of Proteins of Immunological Interest, 5th Ed., US Dept. of Health and Human Services, PHS, NIH, NIH Publication No. 91-3242, 1991.

Unless otherwise specified, an “antibody” refers to an intact immunoglobulin or to an antigen binding portion thereof that competes with the intact antibody for specific binding. Antigen binding portions can be produced by recombinant DNA techniques or by enzymatic or chemical cleavage of intact antibodies. Antigen binding portions include, inter alia, Fab, Fab′, F(ab′)₂, Fv, domain antibodies (dAbs), fragments including complementarity determining regions (CDRs), single-chain antibodies (scFv), chimeric antibodies, diabodies, tribodies, tetrabodies, and polypeptides that contain at least a portion of an immunoglobulin that is sufficient to confer specific antigen binding to the polypeptide.

A Fab fragment is a monovalent fragment having the V_L, V_H, C_Land C_H1regions; a F(ab′)₂fragment is a bivalent fragment having two Fab fragments linked by a disulfide bridge at the hinge region; a Fd fragment has the V_Hand C_H1regions; and a dAb fragment has a V_Hregion, a V_Lregion, or an antigen-binding fragment of a V_Hor V_Lregion (U.S. Pat. Nos. 6,846,634, 6,696,245, US App. Pub. Nos. 05/0202512, 04/0202995, 04/0038291, 04/0009507, 03/0039958, Ward et al., 1989, Nature341:544-546).

A single-chain antibody (scFv) is an antibody in which a V_Land a V_Hregion are joined via a linker (e.g., a synthetic sequence of amino acid residues) to form a continuous protein chain wherein the linker is long enough to allow the protein chain to fold back on itself and form a monovalent antigen binding site (see, e.g., Bird et al., 1988, Science242:423-26 and Huston et al., 1988, Proc. Natl. Acad. Sci. USA85:5879-83). Diabodies are bivalent antibodies comprising two polypeptide chains, wherein each polypeptide chain comprises V_Hand V_Lregions joined by a linker that is too short to allow for pairing between two regions on the same chain, thus allowing each region to pair with a complementary region on another polypeptide chain (see, e.g., Holliger et al., 1993, Proc. Natl. Acad. Sci. USA90:6444-48, and Poljak et al., 1994, Structure2:1121-23). If the two polypeptide chains of a diabody are identical, then a diabody resulting from their pairing will have two identical antigen binding sites. Polypeptide chains having different sequences can be used to make a diabody with two different antigen binding sites. Similarly, tribodies and tetrabodies are antibodies comprising three and four polypeptide chains, respectively, and forming three and four antigen binding sites, respectively, which can be the same or different.

Complementarity determining regions (CDRs) and frame work regions (FR) of a given antibody can be identified using the system described by Kabat et al. in Sequences of Proteins of Immunological Interest, 5th Ed., US Dept. of Health and Human Services, PHS, NIH, NIH Publication no. 91-3242, 1991. One or more CDRs can be incorporated into a molecule either covalently or noncovalently to make it an antibody. An antibody can incorporate the CDR(s) as part of a larger polypeptide chain, can covalently link the CDR(s) to another polypeptide chain, or can incorporate the CDR(s) noncovalently. The CDRs permit the antibody to specifically bind to a particular antigen of interest.

An antibody can have one or more binding sites. If there are more than one binding sites, the binding sites can be identical to one another or can be different. For example, a naturally occurring human immunoglobulin typically has two identical binding sites, while a “bispecific” or “bifunctional” antibody has two different binding sites.

The term “murine antibody” includes all antibodies that have one or more variable and constant regions derived from a murine immunoglobulin sequence.

The term “humanized antibody” refers to an antibody that produced by grafting the complementarity determining region sequence of a murine antibody molecule into a human antibody variable region framework.

The term “antigen-binding domain,” “antigen-binding region,” or “antibody-binding site” is a portion of an antibody that comprises amino acid residues (or other portion) interacting with an antigen and contributing to the specificity and affinity of the antibody for the antigen. For antibodies that specifically bind to their antigen, this will include at least a portion of at least one of its CDR regions.

The term “epitope” is the portion of a molecule that is bound by an antibody (e.g., by an antibody). An epitope can comprise non-contiguous portions of the molecule (e.g., in a polypeptide, amino acid residues that are not contiguous in the polypeptide's primary sequence but that, in the context of the polypeptide's tertiary and quaternary structure, are near enough to each other to be bound by an antibody).

The “percent identity” of two polynucleotide or two polypeptide sequences is determined by comparing the sequences using the GAP computer program (a part of the GCG Wisconsin Package, version 10.3 (Accelrys, San Diego, Calif.)) using its default parameters.

The terms “polynucleotide,” “oligonucleotide” and “nucleic acid” are used interchangeably throughout and include DNA molecules (e.g., cDNA or genomic DNA), RNA molecules (e.g., mRNA), analogs of the DNA or RNA generated using nucleotide analogs (e.g., peptide nucleic acids and non-naturally occurring nucleotide analogs), and hybrids thereof. The nucleic acid molecule can be single-stranded or double-stranded. In one embodiment, the nucleic acid molecules of the invention comprise a contiguous open reading frame encoding an antibody of the invention, or a fragment, derivative, mutein, or variant thereof.

Two single-stranded polynucleotides are “the complement” of each other if their sequences can be aligned in an anti-parallel orientation such that every nucleotide in one polynucleotide is opposite its complementary nucleotide in the other polynucleotide, without the introduction of gaps and without unpaired nucleotides at the 5′ or the 3′ end of either sequences. A polynucleotide is “complementary” to another polynucleotide if the two polynucleotides can hybridize to one another under moderately stringent conditions. Thus, a polynucleotide can be complementary to another polynucleotide without being its complement.

The term “vector” is a nucleic acid that can be used to introduce another nucleic acid linked to it into a cell. One type of vector is a “plasmid,” which refers to a linear or circular double stranded DNA molecule into which additional nucleic acid segments can be ligated. Another type of vector is a viral vector (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), wherein additional DNA segments can be introduced into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors comprising a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. An “expression vector” is a type of vectors that can direct the expression of a chosen polynucleotide.

A nucleotide sequence is “operably linked” to a regulatory sequence if the regulatory sequence affects the expression (e.g., the level, timing, or location of expression) of the nucleotide sequence. A “regulatory sequence” is a nucleic acid that affects the expression (e.g., the level, timing, or location of expression) of a nucleic acid to which it is operably linked. The regulatory sequence can, for example, exert its effects directly on the regulated nucleic acid, or through the action of one or more other molecules (e.g., polypeptides that bind to the regulatory sequence and/or the nucleic acid). Examples of regulatory sequences include promoters, enhancers and other expression control elements (e.g., polyadenylation signals). Further examples of regulatory sequences are described in, for example, Goeddel, 1990, Gene Expression Technology: Methods in EnZymology 185, Academic Press, San Diego, Calif. and Baron et al., 1995, Nucleic Acids Res.23:3605-06.

The term “host cell” is a cell that can be used to express a nucleic acid, e.g., a nucleic acid of the invention. A host cell can be a prokaryote, for example,E. coli, or it can be an eukaryote, for example, a single-celled eukaryote (e.g., a yeast or other fungus), a plant cell (e.g., a tobacco or tomato plant cell), an animal cell (e.g., a human cell, a monkey cell, a hamster cell, a rat cell, a mouse cell, or an insect cell) or a hybridoma. Typically, a host cell is a cultured cell that can be transformed or transfected with a polypeptide-encoding nucleic acid, which can then be expressed in the host cell. The phrase “recombinant host cell” can be used to denote a host cell that has been transformed or transfected with a nucleic acid to be expressed. A host cell also can be a cell that comprises the nucleic acid but does not express it at a desired level unless a regulatory sequence is introduced into the host cell such that it becomes operably linked with the nucleic acid. It is understood that the term host cell refers not only to the particular subject cell but to the progeny or potential progeny of such a cell. Because certain modifications may occur in succeeding generations due to, e.g., mutation or environmental influence, such progeny may not, in fact, be identical to the parent cell, but are still included within the scope of the term as used herein.

Endothelin Receptor

Endothelin A receptor (ET_AR) belongs to family A of 7-transmembrane receptors that are coupled to one or more intracellular signaling pathways via heterotrimeric guanine nucleotide-binding proteins (G proteins) (Jelinek et al., 1993, Science259:1614-1616, Segre et al., 1993, Trends Endocrinol. Metab.4:309-314). As used herein, “endothelin receptor” and “ET_AR” are used interchangeably.

In one embodiment, the antibody provided herein can be selected to bind to membrane bound endothelin receptors as expressed on cells, and inhibit or block endothelin signaling through the endothelin receptors. In one embodiment, the antibody provided herein specifically binds to the human endothelin receptor. In a further embodiment, the antibody binding to the human endothelin receptor can also bind to the endothelin receptors of other species, e.g., rat. The examples below provide one method of generating murine antibodies which bind to human membrane-bound endothelin receptors, and in a further embodiment, bind to endothelin receptors of other species.

The polynucleotide and polypeptide sequences for several species of the endothelin receptors are known. SEQ ID NO: 1-SEQ ID NO: 6 present sequences for human, monkey, and rat. The sequence data were obtained from the GeneBank database of the National Center for Biotechnology Information.

Endothelin a Receptor:

Human (Homo sapiens) polynucleotides (SEQ ID NO: 1); accession number: 563938.

Human (Homo sapiens) amino acid (SEQ ID NO: 2); accession number: AAB20278.

Cynomolgus (Homo sapiens) polynucleotides (SEQ ID NO: 3); accession number: JV635771.

Cynomolgus (Homo sapiens) amino acid (SEQ ID NO: 4); accession number: AFJ71111.

Rat (Rattus norvegicus) polynucleotides (SEQ ID NO: 5); accession number: M60786.

Rat (Rattus norvegicus) amino acid (SEQ ID NO: 6); accession number: AAA41114.

Endothelin Receptor A (ET_AR) Antibody

In one embodiment, an ET_AR antibody (for example, a full-length antibody, antibody fragment, antibody derivative, antibody variant, and antibody mutein) is provided herein.

In one embodiment, the ET_AR antibody provided herein comprises 1, 2, 3, 4, 5, or 6 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

Table 1 lists light chain CDR amino acid sequences of the ET_AR antibodies provided herein, as well as their polynucleotides coding sequences. Table 2 lists heavy chain CDR amino acid sequences of the ET_AR antibodies provided herein, as well as their polynucleotides coding sequences.

TABLE 1

light chain CDR amino acid sequences and polynucleotide coding sequences

	CDR1	CDR2	CDR3

A-1	agggccagtcagaacattggc	tatgcttctaagtctatatct	caacatagttatagctggccg
Nucleic Acid	acaagcatacac	(SEQ ID NO: 31)	tggacg
	(SEQ ID NO: 7)		(SEQ ID NO: 49)

A-1	RASQNIGTSIH	YASKSIS	QHSYSWPWT
Amino Acid	(SEQ ID NO: 8)	(SEQ ID NO: 32)	(SEQ ID NO: 50)

A-2	cgagcaagtgaaaatatttac	aatgcaaaaaccttagcagaa	cagcatcattatggtattccg
Nucleic Acid	agttatttagca	(SEQ ID NO: 33)	ttcacg
	(SEQ ID NO: 9)		(SEQ ID NO: 51)

A-2	RASENIYSYLA	NAKTLAE	QHHYGIPFT
Amino Acid	(SEQ ID NO: 10)	(SEQ ID NO: 34)	(SEQ ID NO: 52)

A-3	cagagcctctttgatattgat	ctggtgtctgaattggactct	tggcaaggtacacattttccg
Nucleic Acid	ggaaagacatatttgaat	(SEQ ID NO: 35)	ctcacg
	(SEQ ID NO: 11)		(SEQ ID NO: 53)

A-3	QSLFDIDGKTYLN	LVSELDS	WQGTHFPLT
Amino Acid	(SEQ ID NO: 12)	(SEQ ID NO: 36)	(SEQ ID NO: 54)

A-4	cgggcaagtcaggacattggt	gccacatccagcttagattct	ctacaatatgctagttctccg
Nucleic Acid	ggtagcttaaac	(SEQ ID NO: 37)	tatacg
	(SEQ ID NO: 13)		(SEQ ID NO: 55)

A-4	RASQDIGGSLN	ATSSLDS	LQYASSPYT
Amino Acid	(SEQ ID NO: 14)	(SEQ ID NO: 38)	(SEQ ID NO: 56)

A-5	agggccagccagactattagc	tatgcttcccaatccatctct	caaagtggtaacacctttccg
Nucleic Acid	gacttcttacac	(SEQ ID NO: 39)	tggacg
	(SEQ ID NO: 15)		(SEQ ID NO: 57)

A-5	RASQTISDFLH	YASQSIS	QSGNTFPWT
Amino Acid	(SEQ ID NO: 16)	(SEQ ID NO: 40)	(SEQ ID NO: 58)

A-6	agggcaagtgaggacatacac	ggtgcagccagtttgaaaagt	caacagtataggagtattccg
Nucleic Acid	actcaattagcc	(SEQ ID NO: 41)	tggacg
	(SEQ ID NO: 17)		(SEQ ID NO: 59)

A-6	RASEDIIITQLA	GAASLKS	QQYRSIPWT
Amino Acid	(SEQ ID NO: 18)	(SEQ ID NO: 42)	(SEQ ID NO: 60)

A-7	agatctagtcagtacattgtt	aaagtttccaaccgattttct	tttcaaggttcacattttcca
Nucleic Acid	catagtactggaaccacctat	(SEQ ID NO: 43)	ttcacg
	ttagaa		(SEQ ID NO: 61)
	(SEQ ID NO: 19)

A-7	RSSQYIVHSTGTTYLE	KVSNRFS	FQGSHFPFT
Amino Acid	(SEQ ID NO: 20)	(SEQ ID NO: 44)	(SEQ ID NO: 62)

A-8	agatctagtcattaccttgtt	aaggtttccaaccgattttct	tttcaaggttcacatttccca
Nucleic Acid	catgataacggaaacacctat	(SEQ ID NO: 43)	ttcacg
	gttgaa		(SEQ ID NO: 63)
	(SEQ ID NO: 21)

A-8	RSSHYLVHDNGNTYVE	KVSNRFS	FQGSHFPFT
Amino Acid	(SEQ ID NO: 22)	(SEQ ID NO: 44)	(SEQ ID NO: 62)

A-9	agatctagtcagaacattgtc	aaagtttccaaccgattttct	tttcaaggttcacattttcca
Nucleic Acid	catagtactggaaacacctat	(SEQ ID NO: 43)	ttcacg
	ttagaa		(SEQ ID NO: 61)
	(SEQ ID NO: 23)

A-9	RSSQNIVHSTGNTYLE	KVSNRFS	FQGSHFPFT
Amino Acid	(SEQ ID NO: 24)	(SEQ ID NO: 44)	(SEQ ID NO: 62)

A-10	agtgtcagctcaagtgtaagt	gacacatccaaactggcttct	caccagtggagtactaaccca
Nucleic Acid	tcatacac	(SEQ ID NO: 45)	(SEQ ID NO: 63)
	(SEQ ID NO: 25)

A-10	SVSSSVSYIH	DTSKLAS	HQWSTNPPT
Amino Acid	(SEQ ID NO: 26)	(SEQ ID NO: 46)	(SEQ ID NO: 64)

A-11	agtgccagctcaagtgtaagt	gacacatccaaactggcttct	cagcagtggagtagtaaccca
Nucleic Acid	tacatgtgc	(SEQ ID NO: 45)	cccacg
	(SEQ ID NO: 27)		(SEQ ID NO: 65)

A-11	SASSSVSYMC	DTSKALS	QQWSSNPPT
Amino Acid	(SEQ ID NO: 28)	(SEQ ID NO: 46)	(SEQ ID NO: 66)

A-12	cagggcattaacaattat	tatacatcaactttacagtca	cagcagtttagtaaacttcgg
Nucleic Acid	(SEQ ID NO: 29)	(SEQ ID NO: 47)	aca
			(SEQ ID NO: 67)

A-12	QGINNY	YTSTLQS	QQFSKLRT
Amino Acid	(SEQ ID NO: 30)	(SEQ ID NO: 48)	(SEQ ID NO: 68)

TABLE 2

heavy chain CDR amino acid sequences and polynucleotide coding sequences

	CDR1	CDR2	CDR3

A-1	gggttctcactgaccactt	cacatttggtcggatggtgacacgcg	atgaaggatgatagtcttta
Nucleic Acid	ctggcttgggtgttgcc	ctattacccagccctgaagaac	ctttgacaac
	(SEQ ID NO: 69)	(SEQ ID NO: 91)	(SEQ ID NO: 115)

A-1	GFSLTTSGLGVA	HIWSDGDTRYYPALKN	MKDDSLYFDN
Amino Acid	(SEQ ID NO: 70)	(SEQ ID NO: 92)	(SEQ ID NO: 116)

A-2	ggctacacctttactagct	tacattaatcctgacactgattatag	gcaagtgctggttattattt
Nucleic Acid	actggatacac	tgagtacaat	ttttgacttc
	(SEQ ID NO: 71)	(SEQ ID NO: 93)	(SEQ ID NO: 117)

A-2	GYTFTSYWIH	YINPDTDYSEYN	ASAGYYFFDF
Amino Acid	(SEQ ID NO: 72)	(SEQ ID NO: 94)	(SEQ ID NO: 118)

A-3	ggcctcaacattaaagaca	aggattgatcctgcgaacggtaagaa	ggtaggggggcccac
Nucleic Acid	tctatattcac	ctgcatatgac	(SEQ ID NO: 119)
	(SEQ ID NO: 73)	(SEQ ID NO: 95)
A-3	GLNIKDIYIH	RIDPANGKTAYD	GRGAH
Amino Acid	(SEQ ID NO: 74)	(SEQ ID NO: 96)	(SEQ ID NO: 120)

A-4	ggttactcattcaccaact	atgattgatccttccgatgctgaaac	gcaagaattggcgattacta
Nucleic Acid	actggatacac	tgggttaaat	taatatggactac
	(SEQ ID NO: 75)	(SEQ ID NO: 97)	(SEQ ID NO: 121)

A-4	GYSFTNYWIH	MIDPSDAETGLN	ARIGDYYNMDY
Amino Acid	(SEQ ID NO: 76)	(SEQ ID NO: 98)	(SEQ ID NO: 122)

A-5	ggattcactttcagtgact	gttagtgatggtggtggttccacc	acaagacatgcttcctacta
Nucleic Acid	atcccatgtct		tagctacgaccattctatgg
	(SEQ ID NO: 77)	(SEQ ID NO: 99)	actac
			(SEQ ID NO: 123)

A-5	GFTFSDYPMS	VSDGGGST	TRHASYYSYDHSMDY
Amino Acid	(SEQ ID NO: 78)	(SEQ ID NO: 100)	(SEQ ID NO: 124)

A-6	ggattcactttcagtagct	attagtagtgctggtagtttcacc	gcaagacgggggtacgacgt
Nucleic Acid	ttggcatgtct	(SEQ ID NO: 101)	tgggtgctttgaccac
	(SEQ ID NO: 79)		(SEQ ID NO: 125)

A-6	GFTFSSFGMS	ISSAGSFT	ARRGYDVGCFDH
Amino Acid	(SEQ ID NO: 80)	(SEQ ID NO: 102)	(SEQ ID NO: 126)

A-7	ggattcactttcagtacct	accattaatactaatggtggtaccac	gcaagagactacggggctat
Nucleic Acid	atggcatgtct	ctattatcgagacagtgtgaagggc	ggactac
	(SEQ ID NO: 81)	(SEQ ID NO: 103)	(SEQ ID NO: 127)

A-7	GFTFSTYGMS	TINTNGGTTYYRDSVKG	ARDYGAMDY
Amino Acid	(SEQ ID NO: 82)	(SEQ ID NO: 104)	(SEQ ID NO: 128)

A-8	ggattcactttcagtacct	accataaatactaatggtggtaacac	gcaagagactacggggctat
Nucleic Acid	atggcatgtct	ctattattcagacaatgtgaagggc	ggactac
	(SEQ ID NO: 81)	(SEQ ID NO: 105)	(SEQ ID NO: 127)

A-8	GFTFSTYGMS	TINTNGGNTYYSDNVKG	ARDYGAMDY
Amino Acid	(SEQ ID NO: 82)	(SEQ ID NO: 106)	(SEQ ID NO: 128)

A-9	ggattcactttcagtagtt	accattagtactaatggtgccaccgc	gcaactgaaaagggagctat
Nucleic Acid	atggcatgtct	caattatccagacagtgtgaagggc	gggctac
	(SEQ ID NO: 83)	(SEQ ID NO: 107)	(SEQ ID NO: 129)

A-9	GFTFSSYGMS	TISTNGATANYPDSVKG	ATEKGAMGY
Amino Acid	(SEQ ID NO: 84)	(SEQ ID NO: 108)	(SEQ ID NO: 130)

A-10	gggttttcactgaccactt	cacatttggtgggatgatgataagta	gctcgaagaactgagactat
Nucleic Acid	ctggtatgggtgtaggc	ctataatccatccctgaagagc	gattacgacagtgctatatt
	(SEQ ID NO: 85)	(SEQ ID NO: 109)	actatgctatggactac
			(SEQ ID NO: 131)

A-10	GFSLTTSGMGVG	HIWWDDDKYYNPSLKS	ARRTETMITTVLYYYAMDY
Amino Acid	(SEQ ID NO: 86)	(SEQ ID NO: 110)	(SEQ ID NO: 132)

A-11	ggattttcactgagcactt	cacatttggtgggatgatgataagta	gctcgaaggagggaagttaa
Nucleic Acid	ctggtttgggtgtaggc	ctataatccatcccttaagaga	cttcggtattaactattact
	(SEQ ID NO: 87)	(SEQ ID NO: 111)	attctatggactac
			(SEQ ID NO: 133)

A-11	GFSLSTSGLGVG	HIWWDDDKYYNPSLKR	ARRREVNFGINYYYSMDY
Amino Acid	(SEQ ID NO: 88)	(SEQ ID NO: 112)	(SEQ ID NO: 134)

A-12	ggattcaccttcagtgatt	attagaaatcgggctaatggttacac	gtaagagattcctatcacta
Nucleic Acid	attac	aaca	cgggtacttcgatgtc
	(SEQ ID NO: 89)	(SEQ ID NO: 113)	(SEQ ID NO: 135)

A-12	GFTFSDYY	IRNRANGYTT	VRDSYHYGYFDV
Amino Acid	(SEQ ID NO: 90)	(SEQ ID NO: 114)	(SEQ ID NO: 136)

In one embodiment, the antibody provided herein comprises a sequence that differs from a CDR sequence listed in Table 1 and Table 2 by 5, 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In another embodiment, the antibody provided herein comprises a sequence that differs from a CDR sequence listed in Table 1 and Table 2 by 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In yet another embodiment, the antibody provided herein comprises a sequence that differs from a CDR sequence listed in Table 1 and Table 2 by 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In yet another embodiment, the antibody provided herein comprises a sequence that differs from a CDR sequence listed in Table 1 and Table 2 by 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In still another embodiment, the antibody provided herein comprises a sequence that differs from a CDR sequence listed in Table 1 and Table 2 by 1 amino acid addition, substitution, and/or deletion.

In another embodiment, the ET_AR antibody provided herein (ET_AR-1 antibody) comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

- a. light chain CDR1 amino acid sequences: SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 28, and SEQ ID NO: 30; and
- b. heavy chain CDR1 amino acid sequences: SEQ ID NO: 70, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 76, SEQ ID NO: 78, SEQ ID NO: 80, SEQ ID NO: 82, SEQ ID NO: 84, SEQ ID NO: 86, SEQ ID NO: 88, and SEQ ID NO: 90.

In one aspect, the ET_AR-1 antibody further comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

- a. light chain CDR2 amino acid sequences: SEQ ID NO: 32, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 38, SEQ ID NO: 40, SEQ ID NO: 42, SEQ ID NO: 44, SEQ ID NO: 46, and SEQ ID NO: 48; and
- b. heavy chain CDR2 amino acid sequences: SEQ ID NO: 92, SEQ ID NO: 94, SEQ ID NO: 96, SEQ ID NO: 98, SEQ ID NO: 100, SEQ ID NO: 102, SEQ ID NO: 104, SEQ ID NO: 106, SEQ ID NO: 108, SEQ ID NO: 110, SEQ ID NO: 112, and SEQ ID NO: 114.

In another aspect, the ET_AR-1 antibody further comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

- a. light chain CDR3 amino acid sequences: SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 54, SEQ ID NO: 56, SEQ ID NO: 58, SEQ ID NO: 60, SEQ ID NO: 62, SEQ ID NO: 64, SEQ ID NO: 66, and SEQ ID NO: 68; and
- b. heavy chain CDR3 amino acid sequences: SEQ ID NO: 116, SEQ ID NO: 118, SEQ ID NO: 120, SEQ ID NO: 122, SEQ ID NO: 124, SEQ ID NO: 126, SEQ ID NO: 128, SEQ ID NO: 130, SEQ ID NO: 132, SEQ ID NO: 134, and SEQ ID NO: 136.

In yet another embodiment, the ET_AR antibody provided herein (ET_AR-2 antibody) comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

In one aspect, the ET_AR-2 antibody further comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

- a light chain CDR1 amino acid sequences: SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 28, and SEQ ID NO: 30; and
- b. heavy chain CDR1 amino acid sequences: SEQ ID NO: 70, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 76, SEQ ID NO: 78, SEQ ID NO: 80, SEQ ID NO: 82, SEQ ID NO: 84, SEQ ID NO: 86, SEQ ID NO: 88, and SEQ ID NO: 90.

In another aspect, the ET_AR-2 antibody further comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

In yet another embodiment, the ET_AR antibody provided herein (ET_AR-3 antibody) comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

In one aspect, the ET_AR-3 antibody further comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

In another aspect, the ET_AR-3 antibody further comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

In one embodiment, the ET_AR antibody provided herein comprises:

- a. a light chain CDR1 amino acid sequence independently selected from the list below: SEQ ID NO: 8, SEQ ID NO: 10, SEQ ID NO: 12, SEQ ID NO: 14, SEQ ID NO: 16, SEQ ID NO: 18, SEQ ID NO: 20, SEQ ID NO: 22, SEQ ID NO: 24, SEQ ID NO: 26, SEQ ID NO: 28, and SEQ ID NO: 30;
- b. a light chain CDR2 amino acid sequence independently selected from the list below: SEQ ID NO: 32, SEQ ID NO: 34, SEQ ID NO: 36, SEQ ID NO: 38, SEQ ID NO: 40, SEQ ID NO: 42, SEQ ID NO: 44, SEQ ID NO: 46, and SEQ ID NO: 48;
- c. a light chain CDR3 amino acid sequence independently selected from the list below: SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 54, SEQ ID NO: 56, SEQ ID NO: 58, SEQ ID NO: 60, SEQ ID NO: 62, SEQ ID NO: 64, SEQ ID NO: 66, and SEQ ID NO: 68;
- d. a heavy chain CDR1 amino acid sequence independently selected from the list below: SEQ ID NO: 70, SEQ ID NO: 72, SEQ ID NO: 74, SEQ ID NO: 76, SEQ ID NO: 78, SEQ ID NO: 80, SEQ ID NO: 82, SEQ ID NO: 84, SEQ ID NO: 86, SEQ ID NO: 88, and SEQ ID NO: 90;
- e. a heavy chain CDR2 amino acid sequence independently selected from the list below: SEQ ID NO: 92, SEQ ID NO: 94, SEQ ID NO: 96, SEQ ID NO: 98, SEQ ID NO: 100, SEQ ID NO: 102, SEQ ID NO: 104, SEQ ID NO: 106, SEQ ID NO: 108, SEQ ID NO: 110, SEQ ID NO: 112, and SEQ ID NO: 114; and
- f. a heavy chain CDR3 amino acid sequence independently selected from the list below: SEQ ID NO: 116, SEQ ID NO: 118, SEQ ID NO: 120, SEQ ID NO: 122, SEQ ID NO: 124, SEQ ID NO: 126, SEQ ID NO: 128, SEQ ID NO: 130, SEQ ID NO: 132, SEQ ID NO: 134, and SEQ ID NO: 136.

In one embodiment, the ET_AR antibody provided herein comprises a light chain CDR3 amino acid sequence independently selected from the list below: SEQ ID NO: 50, SEQ ID NO: 52, SEQ ID NO: 54, SEQ ID NO: 56, SEQ ID NO: 58, SEQ ID NO: 60, SEQ ID NO: 62, SEQ ID NO: 64, SEQ ID NO: 66, and SEQ ID NO: 68. In another embodiment, the ET_AR antibody provided herein comprises a heavy chain CDR3 amino acid sequence independently selected from the list below: SEQ ID NO: 116, SEQ ID NO: 118, SEQ ID NO: 120, SEQ ID NO: 122, SEQ ID NO: 124, SEQ ID NO: 126, SEQ ID NO: 128, SEQ ID NO: 130, SEQ ID NO: 132, SEQ ID NO: 134, and SEQ ID NO: 136. In yet another embodiment, the ET_AR antibody comprises a combination of light and heavy chain CDR3 amino acid sequences independently selected from the list below: SEQ ID NO: 50 versus SEQ ID NO: 116, SEQ ID NO: 62 versus SEQ ID NO: 128, SEQ ID NO: 62 versus SEQ ID NO: 130, SEQ ID NO: 64 versus SEQ ID NO: 132, SEQ ID NO: 66 versus SEQ ID NO: 134, and SEQ ID NO: 68 versus SEQ ID NO: 136.

In another embodiment, the ET_AR antibody comprises 1 or 2 amino acid sequences, wherein each amino acid sequence is independently selected from the amino acid sequences listed below:

- a. amino acid sequences of light chain variable domains: SEQ ID NO: 138 (L1), SEQ ID NO: 140 (L2), SEQ ID NO: 142 (L3), SEQ ID NO: 144 (L4), SEQ ID NO: 146 (L5), SEQ ID NO: 148 (L6), SEQ ID NO: 150 (L7), SEQ ID NO: 152 (L8), SEQ ID NO: 154 (L9), SEQ ID NO: 156 (L10), SEQ ID NO: 158 (L11), SEQ ID NO: 160 (L12), SEQ ID NO: 162 (L13), SEQ ID NO: 164 (L14) and amino acid sequences at least 80%, 85%, 90% or 95% identical to one of the amino acid sequences listed above; and
- b. amino acid sequences of heavy chain variable domains: SEQ ID NO: 166 (H1), SEQ ID NO: 168 (H2), SEQ ID NO: 170 (H3), SEQ ID NO: 172 (H4), SEQ ID NO: 174 (H5), SEQ ID NO: 176 (H6), SEQ ID NO: 178 (H7), SEQ ID NO: 180 (H8), SEQ ID NO: 182 (H9), SEQ ID NO: 184 (H10), SEQ ID NO: 186 (H11), SEQ ID NO: 188 (H12), SEQ ID NO: 190 (H13), and SEQ ID NO: 192 (H14), and amino acid sequences at least 80%, 85%, 90% or 95% identical to one of the amino acid sequences listed above.

In yet another embodiment, a polynucleotide coding sequence of the ET_AR antibody provided herein comprises 1 or 2 polynucleotide sequences, wherein each polynucleotide sequence is independently selected from the polynucleotide sequences listed below:

- a. polynucleotide coding sequences of light chain variable domains: SEQ ID NO: 137, SEQ ID NO: 139, SEQ ID NO: 141, SEQ ID NO: 143, SEQ ID NO: 145, SEQ ID NO: 147, SEQ ID NO: 149, SEQ ID NO: 151, SEQ ID NO: 153, SEQ ID NO: 155, SEQ ID NO: 157, SEQ ID NO: 159, SEQ ID NO: 161, SEQ ID NO: 163, and polynucleotide sequences at least 80%, 85%, 90% or 95% identical to one of the polynucleotide sequences listed above, and
- b. polynucleotide coding sequences of heavy chain variable domains: SEQ ID NO: 165, SEQ ID NO: 167, SEQ ID NO: 169, SEQ ID NO: 171, SEQ ID NO: 173, SEQ ID NO: 175, SEQ ID NO: 177, SEQ ID NO: 179, SEQ ID NO: 181, SEQ ID NO: 183, SEQ ID NO: 185, SEQ ID NO: 187, SEQ ID NO: 189, SEQ ID NO: 191, and polynucleotide sequences at least 80%, 85%, 90% or 95% identical to one of the polynucleotide sequences listed above.

In yet another embodiment, the ET_AR antibody provided herein comprises:

- a. an amino acid sequence of light chain variable domain independently selected from the list below: SEQ ID NO: 138 (L1), SEQ ID NO: 140 (L2), SEQ ID NO: 142 (L3), SEQ ID NO: 144 (L4), SEQ ID NO: 146 (L5), SEQ ID NO: 148 (L6), SEQ ID NO: 150 (L7), SEQ ID NO: 152 (L8), SEQ ID NO: 154 (L9), SEQ ID NO: 156 (L10), SEQ ID NO: 158 (L11), SEQ ID NO: 160 (L12), SEQ ID NO: 162 (L13), SEQ ID NO: 164 (L14), and amino acid sequences at least 80%, 85%, 90% or 95% identical to one of the amino acid sequences listed above, and
- b. an amino acid sequence of heavy chain variable domain independently selected from the list below: SEQ ID NO: 166 (H1), SEQ ID NO: 168 (H2), SEQ ID NO: 170 (H3), SEQ ID NO: 172 (H4), SEQ ID NO: 174 (H5), SEQ ID NO: 176 (H6), SEQ ID NO: 178 (H7), SEQ ID NO: 180 (H8), SEQ ID NO: 182 (H9), SEQ ID NO: 184 (H10), SEQ ID NO: 186 (H11), SEQ ID NO: 188 (H12), SEQ ID NO: 190 (H13), SEQ ID NO: 192 (H14), and amino acid sequences at least 80%, 85%, 90% or 95% identical to one of the amino acid sequences listed above.

In yet another embodiment, the ET_AR antibody provided herein comprises:

- a. an amino acid sequence of light chain variable domain independently selected from the list below: SEQ ID NO: 138 (L1), SEQ ID NO: 140 (L2), SEQ ID NO: 142 (L3), SEQ ID NO: 144 (L4), SEQ ID NO: 146 (L5), SEQ ID NO: 148 (L6), SEQ ID NO: 150 (L7), SEQ ID NO: 152 (L8), SEQ ID NO: 154 (L9), SEQ ID NO: 156 (L10), SEQ ID NO: 158 (L11), SEQ ID NO: 160 (L12), SEQ ID NO: 162 (L13), and SEQ ID NO: 164 (L14), and
- b. an amino acid sequence of heavy chain variable domain independently selected from the list below: SEQ ID NO: 166 (H1), SEQ ID NO: 168 (H2), SEQ ID NO: 170 (H3), SEQ ID NO: 172 (H4), SEQ ID NO: 174 (H5), SEQ ID NO: 176 (H6), SEQ ID NO: 178 (H7), SEQ ID NO: 180 (H8), SEQ ID NO: 182 (H9), SEQ ID NO: 184 (H10), SEQ ID NO: 186 (H11), SEQ ID NO: 188 (H12), SEQ ID NO: 190 (H13), and SEQ ID NO: 192 (H14).

In yet another embodiment, the ET_AR antibody provided herein comprises a combination of amino acid sequences of light and heavy chain variable domains independently selected from the list below: SEQ ID NO: 138 and SEQ ID NO: 166 (L1H1), SEQ ID NO: 140 and SEQ ID NO: 168 (L2H2), SEQ ID NO: 142 and SEQ ID NO: 170 (L3H3), SEQ ID NO: 144 and SEQ ID NO: 172 (L4H4), SEQ ID NO: 146 and SEQ ID NO: 174 (L5H5), SEQ ID NO: 148 and SEQ ID NO: 176 (L6H6), SEQ ID NO: 150 and SEQ ID NO: 178 (L7H7), SEQ ID NO: 152 and SEQ ID NO: 180 (L8H8), SEQ ID NO: 154 and SEQ ID NO: 182 (L9H9), SEQ ID NO: 156 and SEQ ID NO: 184 (L10H10), SEQ ID NO: 158 and SEQ ID NO: 186 (L11H11), SEQ ID NO: 160 and SEQ ID NO: 188 (L12H12), SEQ ID NO: 162 and SEQ ID NO: 190 (L13H13), and SEQ ID NO: 164 and SEQ ID NO: 192 (L14H14).

ET_AR antibody provided herein can also be designated using the nomenclature “LxHy”, wherein “x” corresponds to the sequence number of the light chain variable region and “y” corresponds to the sequence number of the heavy chain variable region. For example, L2H1 refers to an antibody with a light chain variable region comprising the amino acid sequence of SEQ ID NO: 140 (L2) and a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 166 (H1).

In yet another embodiment, the ET_AR antibody provided herein comprises a light chain variable domain selected from L1-L14 or a heavy chain variable domain selected from H1-H14, and fragments, derivatives, muteins, or variants thereof.

In yet another embodiment, the ET_AR antibody provided herein comprises a combination of light and heavy chain CDR3 amino acid sequences independently selected from the list below: SEQ ID NO: 138 and SEQ ID NO: 166, SEQ ID NO: 150 and SEQ ID NO: 178, SEQ ID NO: 152 and SEQ ID NO: 180, SEQ ID NO: 154 and SEQ ID NO: 182, SEQ ID NO: 156 and SEQ ID NO: 184, SEQ ID NO: 158 and SEQ ID NO: 186, SEQ ID NO: 160 and SEQ ID NO: 188, SEQ ID NO: 162 and SEQ ID NO: 190, and SEQ ID NO: 164 and SEQ ID NO: 192.

In one embodiment, the ET_AR antibody provided herein comprises light chain variable domain amino acid sequence SEQ ID NO: 138 or heavy chain variable domain amino acid sequence SEQ ID NO: 166. In another embodiment, the ET_AR antibody provided herein comprises the combination of light chain variable domain amino acid sequence SEQ ID NO: 138 and heavy chain variable domain amino acid sequence SEQ ID NO: 166.

In another embodiment, the ET_AR antibody provided herein further comprises an amino acid sequence of a constant domain, wherein the amino acid sequence of the constant domain is independently selected from the amino acid sequences listed below:

- a. light chain constant domain amino acid sequences: SEQ ID NO: 194 and SEQ ID NO: 196; and
- b. heavy chain constant domain amino acid sequence: SEQ ID NO: 198.

In yet another embodiment, the ET_AR antibody provided herein further comprises constant domain amino acid sequences, wherein each constant domain amino acid sequence is independently selected from the combinations of the light chain and heavy chain constant domain amino acid sequences listed below:

- a. a combination of light chain constant domain amino acid sequence SEQ ID NO:194 and heavy chain constant domain amino acid sequence SEQ ID NO: 198; and
- b. a combination of light chain constant domain amino acid sequence SEQ ID NO:196 and heavy chain constant domain amino acid sequence SEQ ID NO: 198.

In one embodiment, a CDR3 sequence of the antibody differs from the combination of SEQ ID NO: 50 and SEQ ID NO: 116 of the light chain and heavy chain CDR3 sequences illustrated above by no more than 6, 5, 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In another embodiment, a light chain CDR3 sequence of the antibody differs from SEQ ID NO: 50 of the light chain CDR3 sequence illustrated above by no more than 6, 5, 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In another embodiment, a light chain CDR3 sequence of the antibody differs from SEQ ID NO: 50 of the light chain CDR3 sequence illustrated above by no more than 6, 5, 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s) and a heavy chain CDR3 sequence of the antibody differs from SEQ ID NO: 116 or SEQ ID NO: 118 of the heavy chain CDR3 sequence illustrated above by no more than 6, 5, 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In another embodiment, the antibody further comprises a combination of 1, 2, 3, 4, 5 or 6 of light and heavy chain CDR sequences illustrated above. In another embodiment, the antibody further comprises a combination of 1, 2, 3, 4, 5 or 6 of light and heavy chain CDR sequences illustrated above, wherein each sequence independently differs from a combination of SEQ ID NO: 50 and SEQ ID NO: 116 of light chain and heavy chain CDR3 sequences by 6, 5, 4, 3, 2 or 1 amino acid addition(s), substitution(s), and/or deletion(s). In another embodiment, the antibody comprises the CDRs of a light chain variable region and the CDRs of a heavy chain variable region illustrated above. In another embodiment, the antibody comprises a combination of 1, 2, 3, 4, 5, and/or 6 of light and heavy chain CDR sequences illustrated above.

In one embodiment, the antibody (such as an antibody or antibody fragment) comprises the amino acid sequence of light chain variable domain L1 illustrated above. In one embodiment, the sequence of the light chain variable domain differs from the sequence of light chain variable domain L1 by 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 amino acid deletion(s), insertion(s), or substitution(s). In another embodiment, the light-chain variable domain comprises an amino acid sequence at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97% or at least 99% identical to the sequence of light chain variable domain L1. In another embodiment, the polynucleotide coding sequence of the light chain variable domain comprises a nucleotide coding sequence at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 97% or at least 99% identical to the polynucleotide coding sequence of L1. In another embodiment, the polynucleotide coding sequence of the light chain variable domain comprises a polynucleotide that hybridizes under moderately stringent conditions to the complement of the polynucleotide coding sequence of light chain variable domain L1. In another embodiment, the polynucleotide coding sequence of the light chain variable domain comprises a polynucleotide that hybridizes under stringent conditions to the complement of the polynucleotide coding sequence of light chain variable domain L1.

In one embodiment, the antibody provided herein include the combination of L1H1, L2H2, L3H3, L4H4, L5H5, L6H6, L7H7, L8H8, L9H9, L10H10, L11H11, L12H12, L13H13 or L14H14; or an isotype thereof (for example, IgA, IgG1, IgG2a, IgG2b, IgG3, IgM, IgE, or IgD) or a Fab or F(ab′)₂fragment thereof.

In one embodiment, the antibody provided herein includes an antibody comprising a combination of L1H1, or a converted isotype antibody thereof (for example, IgA, IgG1, IgG2a, IgG2b, IgG3, IgM, IgE, or IgD) or a Fab or F(ab′)₂fragment thereof.

The antibody (e.g., an antibody, antibody fragment, and antibody derivative) provided herein can comprise any constant region known in the art. The light chain constant region can be, for example, a kappa- or lambda-type light chain constant region, e.g., a murine kappa- or lambda-type light chain constant region. The heavy chain constant region can be, for example, an alpha-, delta-, epsilon-gamma-, or mu-type heavy chain constant regions, e.g., a murine alpha-, delta-, epsilon-, gamma-, or mu-type heavy chain constant region. In one embodiment, the light or heavy chain constant region is a fragment, derivative, variant, or mutein of a naturally occurring constant region.

In one embodiment, the antibody provided herein further comprises a constant light chain κ or λ region or a fragment thereof. The light chain constant region sequence and its polynucleotide coding sequence are provided as follows:

Light Chain Constant Region:

- polynucleotide (κ), (SEQ ID NO: 193); amino acid (κ), (SEQ ID NO: 194)
- polynucleotide (λ), (SEQ ID NO: 195); amino acid (λ), (SEQ ID NO: 196)

In another embodiment, the antibody provided herein further comprises a heavy chain constant region or a fragment thereof. The heavy chain constant region sequence and its polynucleotide coding sequence are provided as follows:

polynucleotide (IgG1), (SEQ ID NO: 197); amino acid (IgG1), (SEQ ID NO: 198)

In one embodiment, the ET_AR antibody provided herein is selected from murine antibodies, humanized antibodies, chimeric antibodies, monoclonal antibodies, polyclonal antibodies, recombinant antibodies, antigen-binding antibody fragments, single-chain antibodies, double-chain antibodies, triple-chain antibodies, tetra-chain antibodies, Fab fragments, F(ab′)x fragments, domain antibodies, IgD antibodies, IgE antibodies, IgM antibodies, IgG1 antibodies, IgG2 antibodies, IgG3 antibodies, and IgG4 antibodies. In another embodiment, the ET_AR antibody provided herein is an ET_AR monoclonal antibody. In yet another embodiment, the ET_AR antibody provided herein is a mouse ET_AR antibody. The ET_AR antibody provided herein is a humanized ET_AR antibody.

Antibodies and Antibody Fragments

In one embodiment, the antibody provided herein is a full-length antibody (including polyclonal, monoclonal, chimeric, humanized or human antibody with full length heavy and/or light chains). In another embodiment, the antibody provided herein is an antibody fragment, for example, F(ab′)₂, Fab, Fab′, Fv, Fc, or Fd fragment, and can be incorporated into single domain antibodies, single-chain antibodies, maxibodies, minibodies, intrabodies, double-chain antibodies, triple-chain antibodies, tetra-chain antibodies, v-NAR and bis-scFv (see e.g., Hollinger and Hudson, 2005, Nature Biotechnology,23, 9, 1126-1136). In another embodiment, the antibody provided herein also includes antibody polypeptides such as those disclosed in U.S. Pat. No. 6,703,199, including fibronectin polypeptide monobodies. In another embodiment, the antibody provided herein also includes other antibody polypeptides disclosed in U.S. Patent Publication 2005/0238646, which are single-chain polypeptides.

In one embodiment, the variable regions of a gene expressing a monoclonal antibody of interest are amplified using nucleotide primers in a hybridoma. These primers can be synthesized by one of ordinary skill in the art, or can be purchased from commercially available sources (see, e.g., Stratagene, La Jolla, Calif.), which sells primers for mouse and human variable regions including, among others, primers for V_Ha, V_Hb, V_Hc, V_Hd, C_H1, V_Land C_Lregions. These primers can be used to amplify heavy or light chain variable regions, which can then be inserted into vectors such as IMMUNOZAP™H or IMMUNOZAP™L (Stratagene), respectively. These vectors can then be introduced intoE. coli, yeast, or mammalian-based systems for expression. Large amounts of a single-chain protein containing a fusion of the V_Hand V_Lregions can be produced using these methods (see Bird el al., 1988, Science242:423-426).

Once antibody-producing cells of the instant invention have been obtained using any above-described immunization and other techniques, the genes of the specific antibodies can be cloned by isolating and amplifying DNA or mRNA therefrom according to standard procedures described herein. The antibodies produced therefrom can be sequenced to identify CDRs, and the coding DNA of the CDRs can be manipulated as described above to generate other antibodies provided herein.

Antibodies provided herein preferably modulate endothelin signaling in the cell-based assay described herein and/or in the in vivo assay described herein and/or cross-block the binding of one of the antibodies described herein and/or are cross-blocked from binding ET_AR by one of the antibodies described herein. Accordingly, such binding agents can be identified using the assays described herein.

In certain embodiments, antibodies are generated by first identifying antibodies that bind to cells overexpressing ET_AR and/or neutralize in the cell-based and/or in vivo assays described herein and/or cross-block the antibodies described herein and/or are cross-blocked from binding ET_AR by one of the antibodies described herein.

It should be understood by one skilled in the art that certain proteins, such as antibodies, can undergo a variety of post-translational modifications. The types and extents of these modifications often depend on the host cell lines used to express the protein as well as the culture conditions. Such modifications can include variations in glycosylation, methionine oxidation, diketopiperizine formation, aspartate isomerization and asparagine deamidation. A frequent modification is the loss of a carboxyl-terminal basic residue (such as lysine or arginine) due to the action of carboxypeptidases (as described in Harris, R. J., 1995, Journal of Chromatography705:129-134).

An alternative method for production of a murine monoclonal antibody is to inject hybridoma cells into the peritoneal cavity of a syngeneic mouse, for example, a mouse that has been treated (e.g., pristine-primed) to promote formation of ascites fluid containing the monoclonal antibody. Monoclonal antibodies can be isolated and purified by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein-A Sepharose, size-exclusion chromatography, and ion-exchange chromatography (see, e.g., Coligan at pages 2.7.1-2.7.12 and pages 2.9.1-2.9.3; Baines et al., “Purification of Immunoglobulin G (IgG),” in Methods in Molecular Biology, Vol. 10, pages 79-104 (The Humana Press, Inc. 1992)). A monoclonal antibody can be purified by affinity chromatography using an appropriate ligand selected based on particular properties of the antibody (e.g., heavy or light chain isotype, binding specificity, etc.). Examples of suitable ligands immobilized on a solid support include Protein A, Protein an anti-constant region (light chain or heavy chain) antibody, an anti-idiotype antibody, and a TGF-β binding protein, or a fragment or variant thereof.

Molecular evolution of the complementarity determining regions (CDRs) in the center of the antibody binding site also has been used to isolate antibodies with increased affinities, for example, antibodies having increased affinities for c-erbB-2, as described by Schier et al., 1996, J. Mol. Biol.263:551-567. Accordingly, such techniques are useful in preparing antibodies of human endothelin A receptor.

Antibodies against human endothelin A receptor can be used, for example, in assays to detect the presence of the endothelin A receptor, either in vitro or in vivo.

Antibodies can also be prepared by any of the conventional techniques. For example, they can be purified from cells that naturally express them (e.g., an antibody can be purified from a hybridoma that produces it) or produced in recombinant expression systems using any technique known in the art. See, for example, Monoclonal Antibodies, Hybridomas: A New Dimension in Biological Analyses, Kennet et al. (eds.), Plenum Press, New York (1980); and Antibodies: A Laboratory Manual, Harlow and Land (eds.), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., (1988). This is discussed in the nucleic acid section below.

Antibodies can be prepared and screened for desired properties by any known techniques. Some techniques relate to the isolation of nucleic acids encoding polypeptide chains (or portions thereof) of related antibodies (e.g., anti-ET_AR antibodies) and manipulation of nucleic acid. Nucleic acids can be fused with another relevant nucleic acid or modified by recombinant DNA techniques (e.g., induced mutations or other conventional techniques) to add, delete or replace one or more amino acid residues.

Where it is desired to improve the affinity of antibodies according to the invention containing one or more of the above-mentioned CDRs, such antibodies can be obtained by a number of affinity maturation protocols, including maintaining the CDRs (Yang et al., 1995, J. Mol. Biol.,254:392-403), chain shuffling (Marks et al., 1992, Bio/Technology,10:779-783), use of mutation strains ofE. coli. (Low et al., 1996, J. Mol. Biol.,250:350-368), DNA shuffling (Patten et al., 1997, Curr. Opin. Biotechnol.,8:724-733), phage display (Thompson et al., 1996, J. Mol. Biol.,256:7-88) and additional PCR techniques (Crameri et al., 1998, Nature,391:288-291). All of these methods or affinity maturation are discussed in Vaughan et al., 1998, Nature Biotechnology,16:535-539).

In one embodiment, fragments of the ET_AR antibody are provided herein. Such fragments can comprise entirely antibody-derived sequences or additional sequences. Examples of antigen binding fragments include Fab, F(ab′)₂, single chain antibodies, diabodies, tribodies, tetrabodies, and domain antibodies. Other examples are provided in Lunde et al., 2002, Biochem. Soc. Trans.30:500-06.

Single chain antibodies can be formed by linking heavy and light chain variable domain (Fv region) fragments via an amino acid bridge (short peptide linker), resulting in a single polypeptide chain. Such single-chain Fvs (scFvs) have been prepared by fusion DNA encoding a peptide linker between DNAs encoding the two variable domain polypeptides (V_Land V_H). The resulting polypeptides can fold back on themselves to form antigen-binding monomers, or they can form multimers (e.g., dimers, trimers, or tetramers), depending on the length of a flexible linker between the two variable domains (Kortt et al., 1997, Prot. Eng.10:423; Kortt et al., 2001, Biomol. Eng.18:95-108). By combining different V_Land V_H-comprising polypeptides, multimeric scFvs that bind to different epitopes can be formed (Kriangkum et al., 2001, Biomol. Eng.18:31-40). Techniques developed for the production of single chain antibodies include those described in U.S. Pat. No. 4,946,778; Bird, 1988, Science242:423; Huston et al., 1988, Proc. Natl. Acad. Sci. USA85:5879; Ward et al., 1989, Nature334:544; de Graaf et al., 2002, Methods Mol. Biol.178:379-87. Single chain antibodies derived from antibodies provided herein including, but not limited to, scFvs comprising the variable domain combination L1H1, are encompassed by the present invention.

Antibodies derived from an antibody can also be obtained, for example, by proteolytic hydrolysis of the antibody, for example, pepsin or papain digestion of a whole antibody according to conventional methods. By way of example, antibody fragments can be produced by enzymatic cleavage of antibodies with pepsin to provide a SS fragment termed F(ab′)₂. This fragment can be further cleaved using a thiol reducing agent to produce 3.5S Fab′ monovalent fragments. Optionally, the cleavage reaction can be performed using a blocking group for the sulfhydryl groups that result from cleavage of disulfide linkages. As an alternative, an enzymatic cleavage using papain produces two monovalent Fab fragments and an Fc fragment directly. These methods are described, for example, by Goldenberg, U.S. Pat. No. 4,331,647, Nisonoffet et al., 1960, Arch. Biochem. Biophys.89:230; Porter, 1959, Biochem. J.73:119; Edelman et al., Methods in Enzymology 1:422 (Academic Press 1967); and by Andrews, S. M. and Titus, J. A. in Current Protocols in Immunology (Coligan J. E., et al., eds), John Wiley & Sons, New York (2003), pages 2.8.1-2.8.10 and 2.10A.1-2.10A.5. Other methods for cleaving antibodies, such as separating heavy chains to form monovalent light-heavy chain fragments (Fd), further cleaving of fragments, or other enzymatic, chemical, or genetic techniques can also be used, so long as the fragments bind to the antigen that is recognized by the intact antibody.

Another form of an antibody fragment is a peptide comprising one or more complementarity determining regions (CDRs) of an antibody. CDRs can be obtained by constructing polynucleotides that encode the CDRs. Such polynucleotides are prepared, for example, by using the polymerase chain reaction to synthesize the variable region using mRNA or antibody-producing cells as a template (see, for example, Larrick et al., 1991, Methods: A Companion to Methods in Enzymology 2:106; Courtenay-Luck, “(Genetic Manipulation of Monoclonal Antibodies,” in Monoclonal Antibodies: Production, Engineering and Clinical Application, Ritter et al. (eds.), page 166 (Cambridge University Press 1995); and Ward el al., “Genetic Manipulation and Expression or Antibodies,” in Monoclonal Antibodies: Principles and Applications, Birch et al., (eds.), page 137 (Wiley-Liss, Inc. 1995). The antibody fragment further can comprise at least one variable region domain of an antibody described herein. Thus, for example, the V region domain can be monomeric and be a V_Hor V_Ldomain, which can bind to ET_AR with an affinity of 1×10⁻⁷M or less as described below.

The variable region domain can be any naturally occurring variable domain or an engineered version thereof. By engineered version is meant a variable region domain that has been created using recombinant DNA engineering techniques. Such engineered versions include those created, for example, from a specific antibody variable region by insertions, deletions, or changes in or to the amino acid sequences of the specific antibody. Particular examples include engineered variable region domains containing at least one CDR and optionally one or more framework amino acids from a first antibody and the remainder of the variable region domain from a second antibody.

The variable region domain can be covalently attached at a C-terminal amino acid to at least one other antibody domain or a fragment thereof. Thus, for example, a V_Hdomain that is present in the variable region domain can be linked to an immunoglobulin C_H1domain or a fragment thereof. Similarly, a V_Ldomain can be linked to a C_Kdomain or a fragment thereof. In this way, for example, the antibody can be a Fab fragment, wherein the antigen binding domain contains associated V_Hand V_Ldomains covalently linked at their C-termini to a C_H1and Cκ domain, respectively. The C_H1domain can be extended with further amino acids, for example to provide a hinge region or a portion of a hinge region domain as found in a Fab′ fragment, or to provide further domains, such as antibody C_H2and C_H3domains.

Derivatives and Variants of Antibodies

The nucleotide sequences of L1 and H1, encoding the corresponding amino acid sequences of A-1, can be altered, for example, by random mutagenesis or by site-directed mutagenesis (e.g., oligonucleotide-directed site-specific mutagenesis) to create an altered polynucleotide comprising one or more particular nucleotide substitutions, deletions, or insertions as compared to the non-mutated polynucleotide. Examples of techniques for making such alterations are described in Walder et al., 1986, Gene42:133; Bauer et al., 1985, Gene37:73; Craik, 1985, BioTechniques,3:12-19; Smith et al., 1981, Genetic Engineering: Principles and Methods, Plenum Press; and U.S. Pat. Nos. 4,518,584 and 4,737,462. These and other methods can be used to make, for example, derivatives of anti-endothelin A receptor antibodies that have a desired property, for example, an increase in affinity, avidity, or specificity for an endothelin receptor or in vivo or in vitro stability, or reduced in vivo side-effects as compared to the underivatized antibody.

Other derivatives of anti-endothelin receptor antibodies within the scope or this invention include covalent or aggregative conjugates or anti-endothelin receptor antibodies, or fragments thereof, with other proteins or polypeptides, such as by expression or recombinant fusion proteins comprising heterologous polypeptides fused to the N-terminus or C-terminus or an anti-endothelin receptor antibody polypeptide. For example, the conjugated peptide can be a heterologous signal (or leader) polypeptide, e.g., the yeast alpha-factor leader or a peptide such as an epitope tag. An antibody containing fusion proteins can comprise peptides added to facilitate purification or identification of antigen binding protein (e.g., poly-His). An antibody also can be linked to the FLAG peptide as described in Hopp et al., 1988, Bio/Technology6:1204, and U.S. Pat. No. 5,011,912. The FLAG peptide is highly antigenic and provides an epitope reversibly bound by a specific monoclonal antibody (mAb), enabling rapid assay and facile purification of an expressed recombinant protein. Reagents useful for preparing fusion proteins in which the FLAG peptide is fused to a given polypeptide are commercially available (Sigma, St. Louis, Mo.). In another embodiment, oligomers that contain one or more antibodies can be employed as endothelin receptor antagonists. Oligomers can be in the form of covalently-linked or non-covalently-linked dimers, trimers, or higher oligomers. Oligomers comprising two or more antibodies are contemplated for use, with one example being a homodimer. Other oligomers include heterodimers, homotrimers, heterotrimers, homotetramers, heterotetramers, etc.

One embodiment is directed to oligomers comprising multiple antibodies joined via covalent or non-covalent interactions between peptide moieties fused to the antibodies. Such peptides can be peptide linkers (spacers), or peptides that have the property of promoting oligomerization. Leucine zippers and certain polypeptides derived from antibodies are among the peptides that can promote oligomerization of antibodies attached thereto, as described in more detail below.

In particular embodiments, the oligomers comprise from two to four antibodies. The antibodies of the oligomer can be in any form, such as any of the forms described above, e.g., variants or fragments. Preferably, the oligomers comprise antibodies that have endothelin receptor binding activity.

In one embodiment, an oligomer is prepared using polypeptides derived from immunoglobulins. Preparation of fusion proteins comprising certain heterologous polypeptides fused to various portions of antibody-derived polypeptides (including the Fc domain) has been described, e.g., by Ashkenazi et al., 1991, PNAS USA88:10535; Byrn et al., 1990, Nature344:677; and Hollenbaugh et al., 1992 “Construction of Immunoglobulin Fusion Proteins”, in Current Protocols in Immunology, Suppl. 4, pages 10.19.1-10.19.11. One embodiment provided herein is directed to a dimer comprising two fusion proteins created by fusing an endothelin receptor binding fragment of an anti-endothelin A receptor antibody to the Fc region of an antibody. The dimer can be made by, for example, inserting a gene fusion encoding the fusion protein into an appropriate expression vector, expressing the gene fusion in host cells transformed with the recombinant expression vector, and allowing the expressed fusion protein to assemble much like antibody molecules, whereupon inter-chain disulfide bonds form between the Fc moieties to yield the dimer.

The term “Fc polypeptide” as used herein includes native and mutein forms of polypeptides derived from the Fc region of an antibody. Truncated forms of such polypeptides containing the hinge region that promotes dimerization also are included. Fusion proteins comprising Fc moieties (and oligomers formed therefrom) offer the advantage of facile purification by affinity chromatography over Protein A or Protein G columns.

One suitable Fc polypeptide, described in PCT application WO 93/10151 (hereby incorporated by reference), is a single chain polypeptide extending from the N-terminal hinge region to the native C-terminus of the Fc region of a human IgG1 antibody. Another useful Fc polypeptide is the Fc mutein described in U.S. Pat. No. 5,457,035 and in Baum et al., 1994, EMBO J.13:3992-4001. The amino acid sequence of this mutein is identical to that of the native Fc sequence presented in WO 93/10151, except that amino acid 19 has been changed from Leu to Ala,amino acid 20 has been changed from Leu to Glu, and amino acid 22 has been changed from Gly to Ala. The mutein exhibits reduced affinity for Fc receptors. In other embodiments, the variable portion of the heavy and/or light chains of an anti-endothelin receptor antibody can be substituted for the variable portion of an antibody heavy and/or light chain.

Alternatively, the oligomer is a fusion protein comprising multiple antibodies, with or without peptide linkers (spacer peptides). Among the suitable peptide linkers are those described in U.S. Pat. Nos. 4,751,180 and 4,935,233.

Another method for preparing oligomeric antibodies involves use of a leucine zipper. Leucine zipper domains are peptides that promote oligomerization of the proteins in which they are found. Leucine zippers were originally identified in several DNA-binding proteins (Landschulz et al., 1988, Science240:1759), and have since been found in a variety of different proteins. Among the known leucine zippers are naturally occurring peptides and derivatives thereof that dimerize or trimerize. Examples of leucine zipper domains suitable for producing soluble oligomeric proteins are described in PCT application WO 94/10308, and the leucine zipper derived from lung surfactant protein D (SPD) described in Hoppe et al., 1994, FEBS Letters344:191, hereby incorporated by reference. The use of a modified leucine zipper that allows for stable trimerization of a heterologous protein fused thereto is described in Fanslow et al., 1994, Semin. Immunol.6:267-78. In one method, recombinant fusion proteins comprising an anti-endothelin receptor antibody fragment or derivative fused to a leucine zipper peptide are expressed in suitable host cells, and the soluble oligomeric anti-endothelin receptor antibody fragments or derivatives that form are recovered from the culture supernatant.

In another embodiment, the antibody derivatives can comprise at least one of the CDRs disclosed herein. For example, one or more CDR can be incorporated into known antibody framework regions (IgG1, IgG2, etc.), or conjugated to a suitable vehicle to enhance the half-life thereof. Suitable vehicles include, but are not limited to Fc, albumin, transferrin, and the like. These and other suitable vehicles are known in the art. Such conjugated CDR peptides can be in monomeric, dimeric, tetrameric, or other form. In one embodiment, one or more water-soluble polymer is bonded at one or more specific position, for example at the amino terminus, of a binding agent. In an example, an antibody derivative comprises one or more water soluble polymer attachments, including, but not limited to, polyethylene glycol, polyoxyethylene glycol, or polypropylene glycol. See, e.g., U.S. Pat. Nos. 4,640,835, 4,496,689, 4,301,144, 4,670,417, 4,791,192 and 4,179,337. In certain embodiments, a derivative comprises one or more of monomethoxy-polyethylene glycol, dextran, cellulose, or other carbohydrate based polymers, poly-(N-vinyl pyrrolidone)-polyethylene glycol, propylene glycol homopolymers, a polypropylene oxide/ethylene oxide co-polymer, polyoxyethylated polyols (e.g., glycerol) and polyvinyl alcohol, as well as mixtures of such polymers. In certain embodiments, one or more water-soluble polymer is randomly attached to one or more side chains. In certain embodiments, PEG can act to improve the therapeutic capacity for a binding agent, such as an antibody. Certain such methods are discussed, for example, in U.S. Pat. No. 6,133,426, which is hereby incorporated by reference for any purpose.

It will be appreciated that an antibody provided herein can have at least one amino acid substitution, providing that the antibody retains binding specificity. Therefore, modifications to the antibody structures are encompassed within the scope of the invention. These can include amino acid substitutions, which may be conservative or non-conservative, that do not destroy the human endothelin receptor binding capability of an antibody. Conservative amino acid substitutions may encompass non-naturally occurring amino acid residues, which are typically incorporated by chemical peptide synthesis rather than by synthesis in biological systems. These include peptidomimetics and other reversed or inverted forms of amino acid moieties. A conservative amino acid substitution can also involve a substitution of a native amino acid residue with a normative residue such that there is little or no effect on the polarity or charge of the amino acid residue at that position. Non-conservative substitutions can involve the exchange of a member of one class of amino acids or amino acid mimetics for a member from another class with different physical properties (e.g., size, polarity, hydrophobicity, charge).

Moreover, one skilled in the art may generate variants to be tested, which contain a single amino acid substitution at each desired amino acid residue. The variants can then be screened using activity assays known to those skilled in the art. Such variants could be used to gather information about suitable variants. For example, if one discovered that a change to a particular amino acid residue resulted in destroyed, undesirably reduced, or unsuitable activity, variants with such a change may be avoided. In other words, based on information gathered from such routine experiments, one skilled in the art can readily determine the amino acids where further substitutions should be avoided either alone or in combination with other mutations.

A skilled artisan will be able to determine suitable variants of the polypeptide as set forth herein using well-known techniques. In certain embodiments, one skilled in the art may identify suitable areas of the molecule that may be changed without destroying activity by targeting regions not to be important for activity. In certain embodiments, one can identify residues and portions of the molecules that are conserved among similar polypeptides. In certain embodiments, even areas that may be important for biological activity or for structure may be subject to conservative amino acid substitutions without destroying the biological activity or without adversely affecting the polypeptide structure. Additionally, one skilled in the art can review structure-function studies identifying residues in similar polypeptides that are important for activity or structure. In view of such a comparison, one can predict the importance of amino acid residues in a protein that correspond to amino acid residues which are important for activity or structure in similar proteins. One skilled in the art may opt for chemically similar amino acid substitutions for such predicted important amino acid residues.

One skilled in the art can also analyze the three-dimensional structure and amino acid sequence in relation to that structure in similar polypeptides. In view of such information, one skilled in the art may predict the alignment of amino acid residues of an antibody with respect to its three dimensional structure. In certain embodiments, one skilled in the art may choose not to make radical changes to amino acid residues predicted to be on the surface of the protein, since such residues may be involved in important interactions with other molecules. A number of scientific publications have been devoted to the prediction of secondary structure. See Moult, 1996, Curr. Op. Biotech.7:422-427; Chou et al., 1974, Biochemistry13:222-245; Chou et al., 1974, Biochemistry113:211-222; Chou et al., 1978, Adv. Enzymol. Relat. Areas Mol. Biol.47:45-148; Chou et al., 1979, Ann. Rev. Biochem.47:251-276 and Chou et al.,Biophys. J.26:367-384. Moreover, computer programs are currently available to assist with predicting secondary structure. For example, two polypeptides or proteins which have a sequence identity of greater than 30%, or similarity greater than 40% often have similar structural topologies. The recent growth of the protein structural database (PDB) has provided enhanced predictability of secondary structure, including the potential number of folds within the structure of a polypeptide or protein. See Holm et al., 1999, Nucl. Acid. Res.27:244-247. It has been suggested (Brenner et al., 1997, Curr. Op. Struct. Biol.7:369-376) that there are a limited number of folds in a given polypeptide or protein and that once a critical number of structures have been resolved, structural prediction will become dramatically more accurate.

Additional methods of predicting secondary structure include “threading” (Jones, 1997, Curr. Opin. Struct. Biol.7:377-87; Sippl et al., 1996, Structure4:15-19), “profile analysis” (Bowie et al., 1991, Science253:164-170; Gribskov et al., 1990, Meth. Enzym.183:146-159; Gribskov et al., 1987, Proc. Nat. Acad. Sci.84:4355-4358), and “evolutionary linkage” (see Holm, supra (1999), and Brenner, supra (1997)). In certain embodiments, variants of antibodies include glycosylation variants, wherein the number and/or type of glycosylation sites have been altered compared to the amino acid sequences of a parent polypeptide. In certain embodiments, variants comprise a greater or lesser number of N-linked glycosylation sites than the native protein. Alternatively, elimination of such a sequence by substitutions removes an existing N-linked carbohydrate chain. Also provided is a rearrangement of N-linked carbohydrate chains, wherein one or more N-linked glycosylation sites (typically those that are naturally occurring) are eliminated and one or more new N-linked sites are created. Additional preferred antibody variants include cysteine variants, wherein one or more cysteine residues are deleted from or substituted for another amino acid (e.g., serine) as compared to the parent amino acid sequence. Cysteine variants can be useful when antibodies must be refolded into a biologically active conformation such as after the isolation of insoluble inclusion bodies. Cysteine variants generally have fewer cysteine residues than the native protein, and typically have an even number to minimize interactions resulting from unpaired cysteines.

Desired amino acid substitutions (whether conservative or non-conservative) can be determined by those skilled in the art at the time such substitutions are desired. In certain embodiments, amino acid substitutions can be used to identify important residues of antibodies to human endothelin receptor, or to increase or decrease the affinity of the antibodies to human endothelin receptor described herein.

According to certain embodiments, preferred amino acid substitutions are those which: (1) reduce susceptibility to proteolysis, (2) reduce susceptibility to oxidation, (3) alter binding affinity for forming protein complexes, (4) alter binding affinities, and/or (4) confer or modify other physiochemical or functional properties on such polypeptides. According to certain embodiments, single or multiple amino acid substitutions (in certain embodiments, conservative amino acid substitutions) can be made in the naturally-occurring sequence (in certain embodiments, in the portion of the polypeptide outside the domain(s) forming intermolecular contacts). In certain embodiments, a conservative amino acid substitution typically cannot substantially change the structural characteristics of the parent sequence (e.g., a replacement amino acid should not break a helix that occurs in the parent sequence, or disrupt other types of secondary structure that characterizes the parent sequence). Examples of art-recognized polypeptide secondary and tertiary structures are described in Proteins, Structures and Molecular Principles (Creighton, Ed., W. H. Freeman and Company, New York (1984)); Introduction to Protein Structure (Branden and Tooze, Eds., Garland Publishing, New York, N.Y. (1991)); and Thornton et al., 1991, Nature354:105, each of which is incorporated herein by reference.

In certain embodiments, antibodies of the invention can be chemically bonded with polymers, lipids, or other moieties.

The antigen binding agents can comprise at least one of the CDRs described herein incorporated into a biocompatible framework structure. In one embodiment, the biocompatible framework structure comprises a polypeptide or portion thereof that is sufficient to form a conformationally stable structural support, or framework, or scaffold, which is able to present one or more sequences of amino acids that bind to an antigen (e.g., CDRs, a variable region, etc.) in a localized surface region. Such structures can be a naturally occurring polypeptide or polypeptide “fold” (a structural motif), or can have one or more modifications, such as additions, deletions or substitutions of amino acids, relative to a naturally occurring polypeptide or fold. These scaffolds can be derived from a polypeptide of any species (or of more than one species), such as a human, other mammal, other vertebrate, invertebrate, plant, bacteria or virus.

Typically, the biocompatible framework structures are based on protein scaffolds or skeletons other than immunoglobulin domains. For example, those based on fibronectin, ankyrin, lipocalin, neocarzinostain, cytochrome b, CP1 zinc finger, PST1, coiled coil, LACI-D1, Z domain and tendamistat domains can be used (see, e.g., Nygren and Uhlen, 1997, Current Opinion in Structural Biology7:463-469).

Additionally, one skilled in the art will recognize that suitable binding agents include portions of these antibodies, such as one or more of heavy chain CDR1, CDR2, CDR3, light chain CDR1, CDR2 and CDR3 as specifically disclosed herein. At least one of the regions of heavy chain CDR1, CDR2, CDR3, CDR1, CDR2 and CDR3 can have at least one amino acid substitution, provided that the antibody retains the binding specificity of the non-substituted CDR. The non-CDR portion of the antibody can be a non-protein molecule, wherein the binding agent cross-blocks the binding of an antibody disclosed herein to human endothelin receptor and/or inhibits the activity of endothelin-1 signaling through the receptor. The non-CDR portion of the antibody can be a non-protein molecule in which the antibody exhibits a similar binding pattern to human endothelin receptor peptides in a competition binding assay as that exhibited by at least one of antibodies A1/A2, and/or neutralizes the activity of endothelin-1. The non-CDR portion of the antibody can be composed of amino acids, wherein the antibody is a recombinant binding protein or a synthetic peptide, and the recombinant binding protein cross-blocks the binding of an antibody disclosed herein to human ET_AR and/or neutralizes endothelin-1 activity in vitro or in vivo. The non-CDR portion of the antibody can be composed of amino acids, wherein the antibody is a recombinant antibody, and the recombinant antibody exhibits a similar binding pattern to human ET_AR peptides in a competition binding assay as exhibited by at least one of the antibodies A1/A2, and/or neutralizes endothelin-1 signaling.

Nucleic Acids

In one aspect, the present invention provides isolated nucleic acid molecules that encode the antibodies provided herein. The nucleic acids comprise, for example, polynucleotides that encode all or part of an antibody, for example, one or both chains of an antibody of the invention, or a fragment, derivative, mutein, or variant thereof; polynucleotides sufficient for use as hybridization probes; PCR primers or sequencing primers for identifying, analyzing, mutating or amplifying a polynucleotide encoding a polypeptide; anti-sense nucleic acids for inhibiting expression of a polynucleotide, and complementary sequences of the foregoing. he nucleic acids can be any length. They can be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 750, 1,000, 1,500, 3,000, 5,000 or more nucleotides in length, and/or can comprise one or more additional sequences, for example, regulatory sequences, and/or be part of a larger nucleic acid, for example, a vector. The nucleic acids can be single-stranded or double-stranded and can comprise RNA and/or DNA nucleotides, and artificial variants thereof (e.g., peptide nucleic acids).

Nucleic acids encoding antibody polypeptides (e.g., heavy or light chain, variable domain only, or full length) can be isolated from B-cells of mice that have been immunized with ET_AR antigen. The nucleic acid can be isolated by conventional procedures such as polymerase chain reaction (PCR).

Nucleic acid sequences encoding the variable regions of the heavy and light chain variable regions are shown above. The skilled artisan will appreciate that, due to the degeneracy of the genetic code, each of the polypeptide sequences disclosed herein is encoded by a large number of other nucleic acid sequences. The present invention provides each degenerate nucleotide sequence encoding each antibody of the invention.

The invention further provides nucleic acids that hybridize to other nucleic acids (e.g., nucleic acids comprising a nucleotide sequence of any of A-1/A-2) under particular hybridization conditions. Methods for hybridizing nucleic acids are well-known in the art. See, e.g., Current Protocols in Molecular Biology, John Wiley & Sons, N.Y. (1989), 6.3.1-6.3.6. As defined herein, for example, a moderately stringent hybridization condition uses a prewashing solution containing 5× sodium chloride/sodium citrate (SSC), 0.5% SDS, 1.0 mM EDTA (pH 8.0), hybridization buffer of about 50% formamide, 6×SSC, and a hybridization temperature of 55° C. (or other similar hybridization solutions, such as one containing about 50% formamide, with a hybridization temperature of 42° C.), and washing conditions of 60° C., in 0.5×SSC, 0.1% SDS. A stringent hybridization condition hybridizes in 6×SSC at 45° C., followed by one or more washes in 0.1×SSC, 0.2% SDS at 68° C. Furthermore, one of skill in the art can manipulate the hybridization and/or washing conditions to increase or decrease the stringency of hybridization such that nucleic acids comprising nucleotide sequences that are at least 65, 70, 75, 80, 85, 90, 95, 98 or 99% identical to each other typically remain hybridized to each other. The basic parameters affecting the choice of hybridization conditions and guidance for devising suitable conditions are set forth by, for example, Sambrook, Fritsch, and Maniatis (1989, Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.,chapters 9 and 11; and Current Protocols in Molecular Biology, 1995, Ausubel et al., Eds., John Wiley & Sons, Inc., sections 2.10 and 6.3-6.4), and can be readily determined by those having ordinary skill in the art based on, for example, the length and/or base composition of the DNA. Changes can be introduced by mutation into a nucleic acid, thereby leading to changes in the amino acid sequence of a polypeptide (e.g., an antibody) that it encodes. Mutations can be introduced using any technique known in the art. In one embodiment, one or more particular amino acid residues are changed using, for example, a site-directed mutagenesis protocol. In another embodiment, one or more randomly selected residues is changed using, for example, a random mutagenesis protocol. No matter how it is made, a mutant polypeptide can be expressed and screened for a desired property.

Mutations can be introduced into a nucleic acid without significantly altering the biological activity of a polypeptide that it encodes. For example, one can make nucleotide substitutions leading to amino acid substitutions at non-essential amino acid residues. In one embodiment, nucleotide sequences provided herein for L1 to L2 and E11 to H2, or fragments, variants, or derivatives thereof, are mutated such that they encode amino acid sequences provided herein for L1 to L2 and E11 to H2, comprising one or more deletions or substitutions of amino acid residues to result in sequences bearing two or more different amino acid residues. In another embodiment, the mutagenesis inserts an amino acid adjacent to one or more amino acid residues shown herein for L1 to L2 and E11 to H2 to result in sequences with two or more different amino acid residues. Alternatively, one or more mutations can be introduced into a nucleic acid that selectively change the biological activity. (e.g., binding to ET_AR) of a polypeptide that it encodes. For example, the mutation can quantitatively or qualitatively change the biological activity. Examples of quantitative changes include increasing, reducing or eliminating the activity. Examples of qualitative changes include changing the antigen specificity of an antibody.

In another aspect, the present invention provides nucleic acid molecules that are suitable for use as primers or hybridization probes for the detection of nucleic acid sequences of the invention. A nucleic acid molecule of the invention can comprise only a portion of a nucleic acid sequence encoding a full-length polypeptide of the invention, for example, a fragment that can be used as a probe or primer or a fragment encoding an active portion (e.g., a ET_AR binding portion) of a polypeptide of the invention.

Probes based on the sequence of a nucleic acid of the invention can be used to detect the nucleic acid or similar nucleic acids, for example, transcripts encoding a polypeptide of the invention. The probe can comprise a label group, e.g., a radioisotope, a fluorescent compound, an enzyme, or an enzyme co-factor. Such probes can be used to identify a cell that expresses the polypeptide.

In another aspect, the vectors provided herein comprise a nucleic acid encoding a polypeptide of the invention or a portion thereof. Examples of vectors include, but are not limited to, plasmids, viral vectors, non-episomal mammalian vectors and expression vectors, for example, recombinant expression vectors.

The recombinant expression vectors provided herein can comprise a nucleic acid of the invention in a form suitable for expression of the nucleic acid in a host cell. The recombinant expression vectors include one or more regulatory sequences, selected on the basis of the host cells to be used for expression, which is operably linked to the nucleic acid sequence to be expressed. Regulatory sequences include those that direct constitutive expression of a nucleotide sequence in many types of host cells (e.g., SV40 early gene enhancer, Rous sarcoma virus promoter and cytomegalovirus promoter), those that direct expression of the nucleotide sequence only in certain host cells (e.g., tissue-specific regulatory sequences, see Voss et al., 1986, Trends Biochem. Sci.11:287, Maniatis et al., 1987, Science236:1237, the disclosure of each of which is incorporated by reference herein in its entirety), and those that direct inducible expression of a nucleotide sequence in response to particular treatment or condition (e.g., the metallothionin promoter in mammalian cells and the tet-responsive and/or streptomycin responsive promoter in both prokaryotic and eukaryotic systems (see Id.). It will be appreciated by those skilled in the art that the design of the expression vector can depend on such factors as the choice of the host cell to be transformed, the level of expression of protein desired, etc. The expression vectors of the invention can be introduced into host cells to thereby produce proteins or peptides, including fusion proteins or peptides, encoded by nucleic acids as described herein.

In another aspect, the present invention provides host cells into which a recombinant expression vector of the invention has been introduced. A host cell can be any prokaryotic cell or eukaryotic cell. Prokaryotic host cells include gram negative or gram positive organisms, for example,E. colior bacilli. Higher eukaryotic cells include insect cells, yeast cells, and established cell lines of mammalian origin. Examples of suitable mammalian host cell lines include Chinese hamster ovary (CHO) cells or their derivatives such as Veggie CHO and related cell lines which grow in serum-free media (see Rasmussen et al., 1998, Cytotechnology28:31) or CHO strain DXB-11, which is deficient in DHFR (see Urlaub et al., 1980, Proc. Natl. Acad. Sci. USA77:4216-20). Additional CHO cell lines include CHO-K1 (ATCC#CCL-61), EM9 (ATCC# CRL-1861), and W20 (ATCC# CRL-1862). Additional host cells include the COS-7 line of monkey kidney cells (ATCC# CRL-1651) (see Gluzman et al., 1981, Cell23:175), L cells, C127 cells, 3T3 cells (ATCC CCL-163), AM-1/D cells (described in U.S. Pat. No. 6,210,924), HeLa cells, BHK (ATCC CRL-10) cell lines, the CV1/EBNA cell line derived from the African green monkey kidney cell line CV1 (ATCC CCL-70) (see McMahan et al., 1991, EMBO J.10:2821), human embryonic kidney cells such as 293, 293 EBNA or MSR 293, human epidermal A431 cells, human Colo205 cells, other transformed primate cell lines, normal diploid cells, cell strains derived from in vitro culture of primary tissue, primary explants, HL-60, U937, HaK or Jurkat cells. Appropriate cloning and expression vectors for use with bacterial, fungal, yeast, and mammalian cellular hosts are described by Pouwels et al. (Cloning Vectors: A Laboratory Manual, Elsevier, N.Y., 1985).

Vector DNA can be introduced into prokaryotic or eukaryotic cells via conventional transformation or transfection techniques. For stable transfection of mammalian cells, it is known that, depending upon the expression vector and transfection technique used, only a small fraction of cells can integrate the foreign DNA into their genome. In order to identify and select these integrants, a gene that encodes a selectable marker (e.g., for resistance to antibiotics) is generally introduced into the host cells along with the gene of interest. Preferred selectable markers include those which confer resistance to drugs, such as G418, hygromycin and methotrexate. Cells stably transfected with the introduced nucleic acid can be identified by drug selection (e.g., cells that have incorporated the selectable marker gene will survive, while the other cells die), among other methods.

The transformed cells can be cultured under conditions that promote expression of a polypeptide, and the polypeptide recovered by conventional protein purification procedures. One such purification procedure is described in the Examples below. Polypeptides contemplated for use herein include substantially homogeneous recombinant mammalian anti-endothelin receptor antibody polypeptides substantially free of contaminating endogenous materials.

Activity of Antibody

In one embodiment, the antibody provided herein specifically binds to an endothelin receptor, inhibits the signaling transduction, and demonstrates a therapeutic biological effect, for example, the attenuation of pulmonary arterial hypertension in an animal model. In another embodiment, a mouse or humanized antibody provided herein specifically binds to a human endothelin receptor. Such an antibody includes an antagonistic or neutralizing antibody that reduces or neutralizes endothelin signaling.

In one embodiment, the K_dof the antibody provided herein binding to a human endothelin receptor ET_AR is ranging approximately from 0.01 nM to 1000 nM, from 0.1 nM to 500 nM, from 0.5 nM to 200 nM, from 1 nM to 200 nM, or from 10 nM to 100 nM. In another embodiment, the K_dof the antibody provided herein binding to a human endothelin receptor ET_AR is approximately from 1 nM to 200 nM. In yet another embodiment, the K_dof the antibody provided herein binding to a human endothelin receptor ET_AR is approximately from 10 nM to 100 nM. In yet another embodiment, the K_dof the antibody provided herein binding to a human endothelin receptor ET_AR is approximately 1 nM, 2 nM, 5 nM, 10 nM, 20 nM, 30 nM, 40 nM, 50 nM, 60 nM, 70 nM, 80 nM, 90 nM, or 100 nM.

In one embodiment, the IC₅₀of the antibody provided herein antagonizing endothelin signaling is ranging approximately from 0.01 nM to 500 nM, from 0.1 nM to 200 nM, from 0.5 nM to 200 nM, from 1 nM to 200 nM, or from 10 nM to 100 nM. In another embodiment, the IC₅₀of the antibody provided herein antagonizing endothelin signaling is approximately from 1 nM to 200 nM. In yet another embodiment, the IC₅₀of the antibody provided herein antagonizing endothelin signaling is approximately from 10 nM to 100 nM. In yet another embodiment, the IC₅₀of the antibody provided herein antagonizing endothelin signaling is approximately 1 nM, 2 nM, 5 nM, 10 nM, 20 nM, 30 nM, 40 nM, 50 nM, 60 nM, 70 nM, 80 nM, 90 nM, or 100 nM.

In one embodiment, the antibody provided herein specifically binds to a human endothelin receptor ET_AR with one or more following properties:

- a. having the same K_das a reference antibody in binding to a human endothelin receptor ET_AR;
- b. having the same IC₅₀as a reference antibody in antagonizing a human endothelin receptor ET_AR activated by endothelin; and
- c. cross-competing binding with a reference antibody to a human endothelin receptor ET_AR.

In one aspect, the reference antibody comprises a combination of light chain variable domain amino acid sequence SEQ ID NO: 138 and heavy chain variable domain amino acid sequence SEQ ID NO: 166. In another aspect, the reference antibody is monoclonal antibody A-1, A-2, A-7, A-9, or A-12.

As used herein, the term “substantially similar” means comparable to, or approximately 100%, 99%, 98%, 97%, 95%, 90%, 85%, 80%, 75%, 70%, 65%, or 50% identical to the IC₅₀or Kb (or K_d) of a reference antibody. In one embodiment, the reference antibody is, for example, an antibody comprising a heavy chain and light chain combination L1H1 or L2H2. In another embodiment, the reference antibody includes A-1.

In one embodiment, the ET_AR antibody provided herein is able to bind to a human endothelin receptor specifically and lower pulmonary arterial hypertension in an animal model. In one embodiment, the pulmonary arterial hypertension is lowered by about 2% compared with an animal without treatment. In another embodiment, the pulmonary arterial hypertension is lowered by about 5% compared with an animal without treatment. In yet another embodiment, the pulmonary arterial pressure is lowered by about 10% compared to an animal without treatment. In yet another embodiment, the pulmonary arterial hypertension is lowered by about 15% compared to an animal without treatment. In yet another embodiment, the pulmonary arterial hypertension is lowered by about 20% compared to an animal without treatment. In yet another embodiment, the pulmonary arterial hypertension is lowered by about 25% compared to an animal without treatment. The amount of reduction of pulmonary arterial hypertension is controlled by dosage. A therapeutically effective dosage is the dosage required to reduce pulmonary arterial hypertension into the normal range for an animal or human patient.

Pharmaceutical Compositions

In one embodiment, the pharmaceutical composition provided herein comprises an ET_AR antibody provided herein and one or more pharmaceutically acceptable carriers.

In one embodiment, a stable pharmaceutical solution formulation of the ET_AR antibody is provided herein. The stable pharmaceutical solution formulation of the ET_AR antibody is stable and efficacious with a longer half-life in vivo, and can be used to effectively treat pulmonary arterial hypertension and related diseases and cancer of a reproductive organ.

In one embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein comprises an ET_AR antibody provided herein and a buffer. In one embodiment, the pH of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is ranging approximately from 4 to 11, from 5 to 7, or from 5 to 6. In another embodiment, the pH of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is approximately from 5 to 7. In yet another embodiment, the pH of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is approximately from 5 to 6. In yet another embodiment, the pH of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is approximately from 5.3 to 6.5. In still another embodiment, the pH of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is about 5.8.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the buffer described herein is ranging approximately from 1 mM to 200 mM, from 2 mM to 50 mM, or from 5 mM to 25 mM. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the buffer described herein is approximately 5 mM, 10 mM, 15 mM, 20 mM, 25 mM, 30 mM, 35 mM, 40 mM, 45 mM, or 50 mM. In still another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the buffer described herein is approximately 10 mM, 15 mM, 20 mM, 25 mM, or 30 mM.

In one embodiment, the buffer described herein comprises one or more selected from: citric acid, salts of citric acid, ascorbic acid, salts of ascorbic acid, gluconic acid, salts of gluconic acid, carbonic acid, salts of carbonic acid, tartaric acid, salts of tartaric acid, succinic acid, salts of succinic acid, acetic acid, salts of acetic acid, phthalic acid, salts of phthalic acid, phosphoric acid, salts of phosphoric acid, hydrochloric acid, Tris, thomethamine, and amino acids. In another embodiment, the buffer described herein is a salt of citric acid. In yet another embodiment, the buffer described herein is sodium citrate. In still another embodiment, the buffer described herein is histidine.

In another embodiment, the stable solution formulation of the ET_AR antibody provided herein also comprises a surfactant.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the surfactant described herein is approximately ranging from 0.001 to 1 weight/volume percent, from 0.01 to 0.5 weight/volume percent, or from 0.01 to 0.1 weight/volume percent. In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the surfactant described herein is approximately from 0.01 to 0.1 weight/volume percent. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the surfactant described herein is approximately 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1 weight/volume percent. In still another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the surfactant described herein is approximately 0.02, 0.03, 0.04, 0.05, or 0.06 weight/volume percent.

In one embodiment, the surfactant described herein is one or more selected from sorbitan fatty acid esters, glycerin fatty acid esters, polyglycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene glycerine fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene hydrogenated castor oils, polyoxyethylene beeswax derivatives, polyoxyethylene fatty acid amides, C10-C18 alkyl sulfates, polyoxyethylene C10-C16 alkyl ether sulfate with an average of 2 to 4 moles of the added oxirane groups, C1-C18 alkyl sulfosuccinate ester salts, natural surfactants, sphingophospholipids, and sucrose esters of C12-C18 fatty acids.

In one embodiment, the surfactant described herein is a polyoxyethylene sorbitan fatty acid ester, e.g., TWEEN-20, TWEEN-40, TWEEN-60 and TWEEN-80. In another embodiment, the surfactant described herein is TWEEN-20 or TWEEN-80.

In another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody also comprises an amino acid protectant.

In one embodiment, in the stable solution formulation of ET_AR antibody provided herein, the concentration of the amino acid protectant described herein is approximately ranging from 1 mM to 500 mM or from 10 mM to 200 mM. In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the amino acid protectant described herein is approximately from 10 mM to 200 mM. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the amino acid protectant described herein is approximately 100 mM, 110 mM, 120 mM, 130 mM, 140 mM, 150 mM, 160 mM, 170 mM, 180 mM, 190 mM, or 200 mM. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the amino acid protectant described herein is approximately 120 mM, 130 mM, 140 mM, 150 mM, or 160 mM.

In one embodiment, the amino acid protectant is one or more selected from histidine, arginine, glycine, and proline. In another embodiment, the amino acid protectant described herein is one or more selected from histidine, arginine, and glycine. In yet another embodiment, the amino acid protectant described herein is arginine or a salt thereof. In still another embodiment, the amino acid protectant described herein is arginine hydrochloride.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately from 10 to 200 mg/mL; the concentration of the surfactant is approximately from 0.01 to 0.1 weight/volume percent; the concentration of the amino acid protectant is approximately from 10 to 200 mM; and the concentration of the buffer is approximately from 1 to 50 mM; wherein the pH of the formulation is approximately from 5 to 7.

In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately 25, 50, 75, or 100 mg/mL; the concentration of the surfactant is approximately 0.04 weight/volume percent; the concentration of the amino acid protectant is approximately 140 mM; and the concentration of the buffer is approximately 20 mM; wherein the pH of the formulation is approximately from 5 to 6.

In yet another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein also comprises a polyol protectant.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the polyol described herein is approximately ranging from 0.1% to 50%, from 1% to 20%, from 1% to 15%, from 2% to 10%, or from 4% to 10%. In another embodiment, in the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, the concentration of the polyol described herein is approximately from 4 to 10 weight/volume percent. In yet another embodiment, in the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, the concentration of the polyol described herein is approximately 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10 weight/volume percent.

In one embodiment, the polyol protectant described herein is sorbitol, mannitol, sucrose, or trehalose. In another embodiment, the polyol protectant described herein is sorbitol or mannitol.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR is approximately from 10 to 200 mg/mL; the concentration of the surfactant is approximately from 0.01 to 0.1 weight/volume percent; the concentration of the polyol protectant is approximately from 1 to 20 weight/volume percent; and the concentration of the buffer is approximately from 1 to 50 mM; wherein the pH of the formulation is approximately from 5 to 7.

In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately 25, 50, 75 or 100 mg/mL; the concentration of the surfactant is approximately 0.04 weight/volume percent; the concentration of the polyol protectant is approximately from 4 to 10 weight/volume percent; and the concentration of the buffer is approximately 20 mM; wherein the pH of the formulation is approximately from 5 to 6.

In another embodiment, the stable solution formulation of the ET_AR antibody provided herein also comprises a metal chelator.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the metal chelator described herein is approximately ranging from 0.001 mM to 1 mM, from 0.005 mM to 0.5 mM, or from 0.01 mM to 0.2 mM. In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the metal chelator described herein is approximately from 0.01 mM to 0.2 mM. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the metal chelator described herein is approximately 0.01 mM, 0.02 mM, 0.03 mM, 0.04 mM, 0.05 mM, 0.06 mM, 0.07 mM, 0.08 mM, 0.09 mM, or 0.1 mM. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the metal chelator described herein is approximately 0.01 mM, 0.02 mM, 0.03 mM, 0.04 mM, 0.05 mM, 0.06 mM, 0.07 mM, 0.08 mM, 0.09 mM, or 0.1 mM. In still another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the metal chelator described herein is approximately 0.03 mM, 0.04 mM, 0.05 mM, 0.06 mM, or 0.07 mM.

In one embodiment, the metal chelator described herein is EDTA, DTPA, or EGTA. In another embodiment, the metal chelator described herein is EDTA.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately from 10 to 200 mg/mL; the concentration of the metal chelator is approximately from 0.01 to 0.2 mM; the concentration of the surfactant is approximately from 0.01 to 0.1 weight/volume percent; the concentration of the amino acid protectant is approximately from 10 to 200 mM; and the concentration of the buffer is approximately from 1 to 50 mM; wherein the pH of the formulation is approximately from 5 to 7.

In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately 25, 50, 75, or 100 mg/mL; the concentration of the metal chelator is approximately 0.05 mM; the concentration of the surfactant is approximately 0.04 weight/volume percent; the concentration of the amino acid protectant is approximately 140 mM; and the concentration of the buffer is approximately 20 mM; wherein the pH of the formulation is approximately from 5 to 6.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately from 10 to 200 mg/mL; the concentration of the metal chelator is approximately from 0.01 mM to 0.2 mM; the concentration of the surfactant is approximately from 0.01 to 0.1 weight/volume percent; the concentration of the polyol protectant is approximately from 1 to 20 weight/volume percent; and the concentration of the buffer is approximately from 1 to 50 mM; wherein the pH of the formulation is approximately from 5 to 7.

In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately 25, 50, or 100 mg/mL; the concentration of the metal chelator is approximately 0.05 mM; the concentration of the surfactant is approximately 0.04 weight/volume percent; the concentration of the polyol protectant is approximately from 4 to 10 weight/volume percent; and the concentration of the buffer is approximately 20 mM; wherein the pH of the formulation is approximately from 5 to 6.

In another embodiment, the stable solution formulation of the ET_AR antibody provided herein also comprises an antioxidant.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the antioxidant described herein is approximately ranging from 0.1 mM to 50 mM, from 0.5 mM to 20 mM, or from 1 mM to 10 mM. In another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the antioxidant described herein is approximately from 1 to 10 mM. In yet another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the antioxidant described herein is approximately 1 mM, 2 mM, 3 mM, 4 mM, 5 mM, 6 mM, 7 mM, 8 mM, 9 mM, or 10 mM. In still another embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the antioxidant described herein is approximately 3 mM, 4 mM, 5 mM, 6 mM, or 7 mM.

In one embodiment, the antioxidant described herein is methionine, vitamin-C, thiosulfate, thiosulfate, or benzyl methionine. In another embodiment, the antioxidant described herein is methionine.

In one embodiment, in the stable solution formulation of the ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately from 10 to 200 mg/mL; the concentration of the antioxidant is approximately from 1 to 10 mM; the concentration of the surfactant is approximately from 0.01 to 0.1 weight/volume percent; the concentration of the amino acid protectant is approximately from 10 to 200 mM; and the concentration of the buffer is approximately from 1 to 50 mM; wherein the pH of the formulation is approximately from 5 to 7.

In another embodiment, in the stable solution formulation of ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately 25, 50, 75, or 100 mg/mL; the concentration of the antioxidant is approximately 5 mM; the concentration of the surfactant is approximately 0.04 weight/volume percent; the concentration of the amino acid protectant is approximately 140 mM; and the concentration of the buffer is approximately 20 mM; wherein the pH of the formulation is approximately from 5 to 6.

In one embodiment, the stable solution formulation of ET_AR antibody provided herein, in the concentration of the ET_AR antibody is approximately from 10 to 200 mg/mL; the concentration of the antioxidant is approximately from 1 mM to 10 mM; the concentration of the surfactant is approximately from 0.01 to 0.1 weight/volume percent; the concentration of the polyol protectant is approximately from 1 to 20 weight/volume percent; and the concentration of the buffer is approximately from 1 to 50 mM; wherein the pH of the formulation is approximately from 5 to 7.

In another embodiment, in the stable solution formulation of ET_AR antibody provided herein, the concentration of the ET_AR antibody is approximately 25, 50, 75, or 100 mg/mL; the concentration of the antioxidant is approximately 5 mM; the concentration of the surfactant is approximately 0.04 weight/volume percent; the concentration of the polyol protectant is approximately from 4 to 10 weight/volume percent; and the concentration of the buffer is approximately 20 mM; wherein the pH of the formulation is approximately from 5 to 6.

In one embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein comprises:

an ET_AR monoclonal antibody, at 10-150 mg/mL;

a metal chelator at 0.1 mM to 1 mM;

a surfactant at 0.01% to 0.1%;

a polyol protectant at 1% to 50% or an amino acid protectant at 10 to 200 mM; and

a buffering system, providing a pH of 5.0-7.0.

In another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein comprises:

an ET_AR monoclonal antibody at 10 to 150 mg/mL;

a metal chelator at 0.02 mM to 0.2 mM;

a surfactant at 0.01% to 0.1%;

a polyol protectant at 1% to 10% or anamino acid protectant 50 to 200 mM; and

a buffering system, providing a pH of 5.3-6.5.

an ET_AR monoclonal antibody at 10 to 150 mg/mL;

a metal chelator at 0-1 mg/mL;

a surfactant at 0-0.1%;

a polyol protectant at 0-50% or an amino acid protectant at 0-200 mM; and

a buffering system, providing a pH of 5.0-7.0.

an ET_AR monoclonal antibody at 10-150 mg/mL;

EDTA at 0-0.1 mg/mL

a surfactant at 0-0.1%;

a polyol protectant at 0-10% or an amino acid protectant at 50-200 mM; and

a buffering system, providing a pH of 5.3-6.5.

In one embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is an aqueous solution. In another embodiment, the stable formulation of the pharmaceutical ET_AR antibody provided herein is a sterile solution.

In one embodiment, the stability of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is determined by the extent of aggregation of the ET_AR antibody. In one embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at about 40° C. and about 75% humidity for 1, 2, 3, 6, 12, or 24 months, contains no more than 20%, 15%, 10%, 8%, 6%, 5,%, 4%, 3%, 2%, 1%, or 0.1% of an aggregated ET_AR antibody. In another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at room temperature and about 65% humidity for 3, 6, 12, or 24 months, contains no more than 20%, 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.1% of an aggregated ET_AR antibody. In yet another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at 2-8° C. for 6, 12, 18, 24, 36 or 48 months, contains no more than 20%, 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.1% of an aggregated ET_AR antibody.

In another embodiment, the stability of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is determined by the extent of degradation of the ET_AR antibody. In one embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at about 40° C. and about 75% humidity for 1, 2, 3, 6, 12 or 24 months, has a degree of degradation of the ET_AR antibody of no more than 20%, 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.1%. In another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at room temperature and about 65% humidity for 3, 6, 12, or 24 months, has a degree of degradation of the ET_AR antibody of no more than 20%, 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.1%. In yet another embodiment, the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at 2-8° C. for 6, 12, 18, 24, 36 or 48 months, has a degree of degradation of the ET_AR antibody of no more than 20%, 15%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, or 0.1%.

In one embodiment, the aggregation of the ET_AR antibody and the loss of a monomeric ET_AR antibody are determined by SEC-HPLC.

In another embodiment, the stability of the stable pharmaceutical solution formulation of the ET_AR antibody provided herein is determined by the change in the biological activity of the ET_AR antibody. In one embodiment, the ET_AR antibody in the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored at about 40° C. and about 75% humidity for 1, 2, 3, 6, 12 or 24 months, has a biological activity of no less than 40%, 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, or 99.9% of its original biological activity. In another embodiment, the ET_AR antibody in the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored under room temperature and about 65% humidity for 3, 6, 12, or 24 months, has a biological activity of no less than 50%, 60%, 70%, 80%, 90%, 92%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.9% of its original biological activity. In yet another embodiment, the ET_AR antibody in the stable pharmaceutical solution formulation of the ET_AR antibody provided herein, after stored under temperature of 2-8° C. for 6, 12, 18, 24, 36 or 48 months, has a biological activity of no less than 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 92%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.9% of its original biological activity.

In one embodiment, the change in the biological activity of the ET_AR antibody is determined by a calcium flux detection method to determine the ability of an ET_AR antibody to inhibit an ET_AR in vitro.

Methods of Treatment

In one embodiment, provided herein is a method of lowering hypertension (for example, PAH) in a subject, comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition provided herein, for example, a stable pharmaceutical solution formulation of an ET_AR antibody provided herein.

In another embodiment, provided herein is a method of treating PAH in a subject, comprising administering to the subject a therapeutically effective amount of a pharmaceutical composition provided herein, for example, a stable pharmaceutical solution formulation of an ET_AR antibody provided herein.

As used herein, the term “subject” refers to a mammal, including humans, and is used interchangeably with the term “patient.” The term “treatment” encompasses alleviation or prevention of at least one symptom or other aspect of a disorder, or reduction of disease severity, and the like. An antibody provided herein needs not to provide a complete cure, or to eradicate every symptom or manifestation of a disease, to be an effective therapeutic agent. As is recognized in the pertinent field, therapeutic agents can reduce the severity of a given disease state, but need not to abolish every manifestation of the disease to be effective. Similarly, a prophylactic agent needs not to prevent the onset of a condition completely in order to be effective. Simply reducing the impact of a disease (for example, by reducing the number or severity of its symptoms, or by increasing the effectiveness of another treatment, or by producing another beneficial effect), or reducing the likelihood that the disease will occur or worsen in a subject, is sufficient. One embodiment of the invention is directed to a method comprising administering to a patient an antibody in an amount and for a time sufficient to induce a sustained improvement over baseline of an indicator that reflects the severity of a particular disorder.

A pharmaceutical composition can be administered by any suitable technique, including, but not limited to, parenterally, topically, or by inhalation. If injected, the pharmaceutical composition can be administered, for example, via an intra-articular, intravenous, intramuscular, intralesional, intraperitoneal or subcutaneous route, by bolus injection or continuous infusion. It is considered, for example, localized administration at the disease or injury site, such as transdermal administration and sustained release of an implant. Delivery by inhalation includes, for example, nasal or oral inhalation, use of a nebulizer, inhalation of an antibody in aerosol form, and the like. Other alternatives include oral preparations, including pills, syrups, or lozenges.

Advantageously, the antibodies provided herein, are administered in a composition comprising one or more additional components such as a physiologically acceptable carrier, excipient or diluent. The composition additionally comprises one or more physiologically active agents as described below. In many particular embodiments, the composition comprises one, two, three, four, five, or six physiologically active agents in addition to one or more antibodies (e.g., murine antibodies or humanized antibodies) provided herein.

In one embodiment, the pharmaceutical composition comprises a murine antibody or humanized antibody of the invention together with one or more substances selected from the group consisting of a buffer suitable for the antibody at a suitable pH, an antioxidant such as ascorbic acid, a low molecular weight polypeptide (such as those having fewer than 10 amino acids), a protein, an amino acid, a carbohydrate such as dextrin, a chelating agent such as EDTA, glutathione, a stabilizer, and an excipient. In accordance with appropriate industry standards, preservatives can also be added. The composition can be formulated as a lyophilizate using appropriate excipient solutions as diluents. Suitable components are nontoxic to recipients at the dosages and concentrations employed. Further examples of components that can be employed in pharmaceutical formulations are presented in Remington's Pharmaceutical Sciences, 16th Ed. (1980) and 20th Ed. (2000). Mack Publishing Company kits for use by medical practitioners are provided, including one or more antibodies of the invention and a label or other instructions for use in treating any of the conditions discussed herein. In one embodiment, the kit includes a sterile preparation of one or more human antibodies, which can be in the form of a composition as disclosed above, and can be in one or more vials.

Dosages and the frequency of administration can vary according to such factors as the route of administration, the particular antibodies employed, the nature and severity of the disease to be treated, whether the condition is acute or chronic, and the size and general condition of the subject. Appropriate dosages can be determined by procedures known in the pertinent art, e.g. in clinical trials that can involve dose escalation studies.

An antibody provided here can be administered, for example, once or more than once, e.g., at regular intervals over a period of time. In particular embodiments, a murine antibody or humanized antibody is administered over a period of at least once a month or more, e.g., for one, two, or three months or even indefinitely. For treating chronic conditions, long-term treatment is generally most effective. However, for treating acute conditions, administration for shorter periods, e.g., from one to six weeks, can be sufficient. In general, the humanized antibody is administered until the patient manifests a medically relevant degree of improvement over baseline for the chosen indicator or indicators.

One example of therapeutic regimens provided herein comprise subcutaneous injection of an antibody once a week, at an appropriate dosage, to treat a condition in which pulmonary arterial pressure levels play a role. Weekly or monthly administration of antibody would be continued until a desired result is achieved, e.g., the subject's symptoms subside. Treatment can resume as needed, or, alternatively, maintenance doses can be administered.

A subject's levels of pulmonary arterial pressure can be monitored before, during and/or after treatment with an antibody such as a humanized antibody, to detect changes, if any, in their levels. For some disorders, the incidence of elevated pulmonary arterial pressure can vary according to such factors as the stage of the disease. Known techniques can be employed for measuring pulmonary arterial pressure levels.

Particular embodiments of methods and compositions of the invention involve the use of an antibody and one or more ET_AR antagonists for example, two or more antibodies of the invention, or an antibody of the disclosure and one or more other ET_AR antagonists. In further embodiments, an antibody is administered alone or in combination with other agents useful for treating the condition with which the patient is afflicted. Examples of such agents include both proteinaceous and non-proteinaceous drugs. When multiple therapeutics are co-administered, dosages can be adjusted accordingly, as is recognized in the pertinent art. “Co-administration” and combination therapy are not limited to simultaneous administration, but also include treatment regimens in which an antibody is administered at least once during a course of treatment that involves administering at least one other therapeutic agent to the patient.

In another aspect, the method of preparing a medicament for treating pulmonary arterial hypertension and related disorders comprises a mixture of the antibody provided herein and pharmaceutically acceptable excipients. The preparation method of the medicament was as described above.

A composition, kit, and method related to an antibody specifically binding to a human endothelin receptor are further provided herein. Nucleic acid molecules and derivatives and fragments thereof comprising a part of or a full polynucleotide encoding a polypeptide interacting with an ET_AR, for example, nucleic acids encoding all or part of an endothelin receptor antibody, an antibody fragment or an antibody derivative, are also provided. A vector and plasmid comprising nucleic acids and cells and cell line comprising nucleic acids and/or a vector and plasmid are further provided herein. Methods provided herein include, for example, methods for preparation, identification or separation of an antibody interacting with a human ET_AR, for example, a method of an ET_AR antibody, a method for determining whether an antibody binds to ET_AR, and a method for administering an antibody binding to an ET_AR to an animal model.

The technical solutions described herein will be further understood by the following examples.

EXAMPLES

If not specified, the starting materials and equipment described herein are commercially available or commonly used in the art. The methods in the following examples, unless otherwise specified, are all conventional methods in the art.

1. Construction of a Stable Antigen Cell Line for Immunization

CHO-DHFR-cells were seeded into a 6-well plate. After 24 h culture, the cells were transfected with a pIRES plasmid (Clontech, commercial) modified to carry hET_AR gene (see SEQ ID NO: 1 for the nucleotide sequence, and SEQ ID NO: 2 for the amino acid sequence). The transfection was carried out by following the transfection conditions recommended by Invitrogen for Lipofectamine 2000. Forty-eight hours after transfection, the medium was replaced with a complete medium containing 10 nM MTX (methotrexate). The medium was changed every 3 days for about two weeks until stable clones appeared. The dispersed cell colonies were detached from the plate and collected. After cells grew to about 50% confluence, the concentration of MTX was graduately increased for pressure selection up to 10 μM. The constructed stable cell lines were analyzed by FACS using a polyclonal antibody (Abcam) against hET_AR to identify cell clones after pressure selection. A large amount of hET_AR expression were detected on the selected CHO-DHFR-hET_AR cell membranes. Finally through subcloning, six high-ET_AR expression and stable cell lines were identified and obtained.

2. Preparation of Antibodies

An emulsion of the CHO-DHFR-hET_AR whole cells and Freund's adjuvant was injected subcutaneously into BALB/c mice (6-8 weeks) at 2×10⁶cells/mouse. After 2 weeks, the mice were boosted with incomplete Freund's adjuvant emulsified immunogen and then boosted once every week. After immunization for 6 times in total, blood samples were collected from the clipped tail ends and centrifuged to collect the serum. The serum was analyzed for serum titers by FACS. After the acceptable antibody titers were achieved, the mice were sacrificed and their spleen cells were harvested under aseptic conditions. SP2/0 cells were collected at the logarithmic phase of growth with 3 min centrifugation at 2,000 rpm. The cell pellets were resuspended with serum-free culture medium, then centrifuged, resuspended for a second time and counted. Spleen cells and SP2/0 cells were mixed at ratio of SP2/0 cells:spleen cells ≥1:1, followed by 3 rounds of washing-centrifugation. After the pellets from the last centrifugation were detached, 1 mL of pre-warmed PEG-1350 was added dropwise (finished in 30 s), after pipette-mixing for 1 min, 30 mL of the pre-warmed serum-free medium (Invitrogen) was added slowly to terminate the PEG fusion. After 5 min centrifugation at 1,500 rpm, the cell pellets were resuspended in the fusion culture medium. Spleen cells (20,000) and feeder layer cells (5,000) in 100 μL were plated into each well of 96-well plates. Fused hybridoma cells and feeder layer cells were co-cultured in 96-well plates with HAT (sarcine, amethopterin and thymidine) selection to get rid of the non-fused cells. After 10 days, the supernatants of the hybridoma cells in the culture plates were collected for ELISA analysis.

3. ELISA Screening of Whole Cells

CHO-DHFR-hET_AR cells over-expressing hET_AR and CHO-DHFR-cells not expressing hET_AR were separately transferred into a 96-well plate and allowed to grow to 90% confluent. The supernatant of the culture medium was removed and attached cells were washed twice with PBS, then 100 μL, 100% methanol was added to fix the cells for 10 min at 4° C. Then 100 μL freshly made 0.6% H₂O₂-PBS was added, and after incubation at room temperature for 20 min, the cells were washed twice with PBS. After blocked with PBS-1% BSA solution, the hybridoma supernatant was added and incubated for 90 min at 4° C. After several washes, 100 μL of the secondary antibody GxM-HRP-Fc (Sigma-Aldrich) was added into each well and incubated at 37° C. for 0.5 h. After five washings, 100 μL of TMB chromogenic substrate was added into each well and incubated at 37° C. for 15 min, and then 2M H2504 was added to terminate, read for OD₄₅₀values. The positive control was the mouse serum after immunization; the negative control was the cell culture supernatant. As shown inFIG. 1, after initial analysis by ELISA, several hybridoma clones secreting anti-hET_AR antibodies were selected, and the stable secretory cell lines against hET_AR were obtained after cell cloning. Lastly, antibody supernatant secreted by hybridoma was verified by FACS analysis.

4. Cloning and Subcloning of Antibody Genes

Hybridoma cells secreting antibodies were collected. Hybridoma mRNA was extracted according to the manufacturer protocol of QIAGEN mRNA extraction kit. Then the extracted mRNA was transcribed reversely into cDNA. The reverse transcription primers were specific primers for the light and heavy chain constant regions of a mouse, with the heavy chain reverse transcription primer being (5′-TTTGGRGGGAAGATGAAGAC-3′) (SEQ ID NO: 199), the light chain reverse transcription primers being (5′-TTAACACTCTCCCCTGTTGAA-3′) (SEQ ID NO: 200) and (5′-TTAACACTCATTCCTGTTGAA-3′) (SEQ ID NO: 201). RT-PCR reaction conditions were as following: 25° C. for 5 min, 50° C. for 60 min, and 70° C. for 15 min. Reversely transcribed cDNA was diluted with 0.1 mM TE to 500 μL, added into the ultrafiltration centrifuge tube (Amicon Ultra-0.5) and centrifuged at 2,000 g for 10 min. The filtrate was removed, 500 μL of 0.1 mM TE were added and centrifuged at 2,000 g for 10 min. The filtrate was removed and the preparation tube was placed in inversion to the new centrifugal tube, and centrifuged at 2,000 g for 10 min to obtain the purified cDNA. Purified cDNA (10 μL) was taken as a template, followed by addition of 4 μL 5× tailing buffer (Promega), 4 μL dATP (1 mM) and 10 U terminal transferase (Promega), mixing uniformly, and incubation at 37° C. for 5 min and then at 65° C. for 5 min. The PolyA tail cDNA was used as a template and PCR was performed to amplify light and heavy chain variable region genes of antibodies. Upstream primers were all oligodT, with heavy chain downstream primers being (5′-TGGACAGGGATCCAGAGTTCC-3′) (SEQ ID NO: 202) and (5′-TGGACAGGGCTCCATAGTTCC-3′) (SEQ ID NO: 203), and light chain downstream primer being (5′-ACTCGTCCTTGGTCAACGTG-3′) (SEQ ID NO: 204). The PCR reaction conditions were: 95° C. for 5 min; 95° C. for 30 s, 56° C. for 30 s, 72° C. for 1 min, 40 cycles; and 72° C. for 7 min. The PCR products were connected to the PMD 18-T vector (Takara Bio) for sequencing. The sequences of the antibody clones were listed in Table 2.

PCR primers were designed based on the DNA sequences of the antibodies, thus the complete light chain, heavy chain signal peptides and variable domains and mouse IgG1 constant region were ligated into expression vector pTM5.

5. Antibody Humanization and Optimization

First of all, the sequences of light and heavy chain variable regions of the screened mouse antibodies were aligned with the homologous antibodies, using NCBI online antibody variable region sequence alignment tool (Ig Blast) to search the germline gene sequences of a humanized antibody (Ig Germline Gene sequence) homologous to the selected antibodies variable region sequence for humanization, and the humanized gene sequence with highest homology except CDR sequences was used as a template for CDR grafting to obtain humanized antibody variable region sequences and to synthesize humanized antibody light and heavy chain genes through a CRO. According to the sequences, PCR primers were designed and appropriate restriction enzyme sites were introduced at the 5′ ends and 3′ ends. By PCR, the humanized antibody variable regions were amplified and then combined with the human IgG2 or IgG4 constant region sequence to obtain whole recombinant humanized antibody sequences. The expression of the recombinant antibodies was achieved according tostep 7, and their affinities to ET_AR was analyzed by FACS as described instep 9. The best humanized antibody candidate retaining affinity to ET_AR was selected from the group, and its variable region sequence was further improved by site-specific mutagenesis for improved affinity to ET_AR.

6. Subcloning of Genes of a Humanized Anti-hET_AR Antibody

The heavy and light chain variable region gene sequences of an optimized humanized antibody were synthesized by Genscript Biotechnology CO., LTD by introducing two restriction sites of NheI at the 5′-end and SalI at the 3′-end. The whole heavy chain variable region was ligated with a heavy chain constant region in an expression vector of pTM5. Similarly, by introducing NheI at the 5′-end and BsiwI at the 3′-end, the light chain variable region was ligated with a light chain constant region in the expression vector of pTM5.

7. Transient Expression of Anti-ET_AR Antibodies

A suspension of an HEK293 or CHO expressing cell line (5×10⁵/mL) was inoculated to a shaker flask. After 24 h rotation at 37° C., the cell density reached 1×10⁶/mL and were ready for transfection. Polyethylenimine (PEI) was used as a transfection reagent with an optimal mixing ratio of 3:1 for PEI to DNA (DNA amount, 0.5 μg/L×10⁶cells; the ratio of the antibody light chain DNA and antibody heavy chain DNA, 3:2). A mixture of both was added into the cell culture after 15 min incubation. The cells after treated with the PEI/DNA mixture were rotated for more than 24 h at 37° C. and 5% CO₂. Then 0.5% of tryptone was added into the cell culture as a supplement required by expression, and after the completion of expression (more than 96 h), the cell supernatant was collected for the antibody purification and separation.

8. Purification and Preparation of Antibody

Cells and cellular debris were removed from the culture after centrifugation (8000 rpm, 15 min), and the supernatant was filtered through 0.45 μm filter for purification. The purification process was done through chromatography. First, the supernatant was passed through a G protein coupled affinity chromatography column, and antibodies bound to the G proteins remained in the column. The antibodies were eluted from the chromatography column using an eluent with pH of 3.0 or less. The low pH eluent was neutralized immediately with 1M Tris-HCl to keep the antibodies from denaturation and loss of activity. The antibody solution was then dialyzed over 16 h into a PBS buffer.

9. FACS Analysis of a Functional Antibody

PBS containing 10 mM EDTA was used to detach and collect 10⁵CHO-DHFR-hET_AR cells into a 1.5 mL EP tube. The supernatant was removed after centrifugation and the negative control sample was resuspended with a loading buffer (PBS, 2% FBS). For the positive control, 200 μL antibody supernatant was added to resuspension cells and incubation at room temperature; the cells were then centrifuged at 1500 rpm to remove the supernatant, washed with a FACS loading buffer and centrifuged again. The cells were resuspended with addition (200 μL/well) of a FITC labeled goat anti-mouse fluorescent antibody at 1:50 dilution (BD Pharmingen) and incubated at room temperature for 30 min in the dark. Supernatant was removed after centrifugation, cells were washed with FACS loading buffer, centrifuged again and resuspended with the loading buffer for analysis. The recombinant antibody supernatant and CHO-DHFR-hET_AR cells had specific binding. Gray peak and dotted line peak were negative controls; the solid line peak, corresponding to the antibody supernatant, moved to the right significantly.

10. Calcium Influx Assay for a Functional Antibody

CHO-DHFR cells co-expressing hET_AR-Aequorin were seeded into a 96-well cell culture plate with 25000 cells per well and cultured at 37° C. overnight. The next day the culture supernatant was removed. Coelenterazine (50 μL) (Promega) was added in the dark and incubated at 37° C. for 2 h, and then 50 μL of a hybridoma supernatant or a purified antibody were added and incubated at 37° C. for 30 min. After the incubation, 50μL endothelin 1 was added and the changes of calcium influx within 40 s were recorded by a SpectraMax L microplate reader (Molecular Devices). Different hybridoma supernatants inhibited the calcium influx mediated through hET_AR differently, and A-1 antibody significantly inhibited the calcium influx mediated through hET_AR. The recombinant anti-hET_AR functional antibody significantly inhibited calcium influx mediated through hET_AR, increasing with an increase in the antibody concentration.

11. Establishment of Hypoxia-Induced PAH Cynomolgus Model to Study the In Vivo Activity of an Antibody

The acute hypoxia-induced pulmonary arterial hypertension (PAH) model of cynomolgus was codeveloped with Crown Bioscience Inc. (Taicang), and the efficacy of A-1 antibody as a single intravenous injection was evaluated in this PAH model. All animals were fasted overnight and weighed, and then received a single intravenous injection of 10 mg/kg of A-1 antibody. Three hours later, the animals were anesthetized. The tricuspid regurgitation velocity by Doppler color echocardiography along with heart rate and oxygen saturation were monitored simultaneously. The baseline was obtained and the induction of 12% hypoxia was followed and at the same time the tricuspid regurgitation velocity was measured; Analysis was made to determine if the antibody would improve hypoxia-induced pulmonary arterial pressure under 12% hypoxia. After 48 h of administration, the tests were performed again. The animals were anesthetized, the tricuspid regurgitation velocity by Doppler color echocardiography along with heart rate and oxygen saturation were monitored simultaneously. The baseline was obtained and the induction of 12% hypoxia was followed and at the same time the tricuspid regurgitation velocity was measured. Analysis was made to determine if the antibody would still improve hypoxia-induced pulmonary arterial pressure. If the efficacy maintained after 48 h, 96 h later, hypoxia induction experiment was performed again. The area under the curve of pulmonary artery systolic pressure versus time was calculated, and by comparing the area under the curve, it was found that A-1 maintained the efficacy of reducing pulmonary artery pressure within 96 h.

12. Stable Pharmaceutical Solution Formulations of an ET_AR Antibody:

The followings are examples of stable pharmaceutical solution formulations of an ET_AR antibody:

Example 1


	Ingredients	Concentration

	ET_AR antibody A-1	25 mg/mL
	Sodium citrate
	20 mM
	Arginine hydrochloride	140 mM
	TWEEN-80	0.04%

The pH of the stable solution formulation of Example 1 is 5.8.

Example 2


	Ingredients	Concentration

	ET_AR antibody A-1	50 mg/mL
	Histidine
	20 mM
	Arginine hydrochloride	140 mM
	TWEEN-80	0.04%

The pH of the stable solution formulation of Example 2 is 5.8.

Example 3


	Ingredients	Concentration

	ET_AR antibody A-1	50 mg/mL
	Sodium citrate
	20 mM
	Sorbitol	4.5%
	TWEEN-80	0.04%

The pH of the stable solution formulation of Example 3 is 5.8.

Example 4


	Ingredients	Concentration

	ET_AR antibody A-1	25 mg/mL
	Sodium citrate
	20 mM
	Mannitol	4.5%
	TWEEN-80	0.04%

The pH of the stable solution formulation of Example 4 is 5.8.

Example 5


	Ingredients	Concentration

	ET_AR antibody A-1	25 mg/mL
	Sodium citrate
	20mM
	Sucrose
	9%
	TWEEN-80	0.04%

The pH of the stable solution formulation of Example 5 is 5.8.

Example 6


	Ingredients	Concentration

	ET_AR antibody A-1	25 mg/mL
	Histidine
	20mM
	Sucrose
	9%
	TWEEN-80	0.04%

The pH of the stable solution formulation of Example 6 is 5.8.

Example 7


	Ingredients	Concentration

	ET_AR antibody A-1	50 mg/mL
	Histidine
	20 mM
	Arginine hydrochloride	140 mM
	Methionine	5 mM
	TWEEN-20	0.04%

The pH of the stable solution formulation of Example 7 is 5.8.

Example 8


	Ingredients	Concentration

	ET_AR antibody A-1	50 mg/mL
	Sodium citrate
	20 mM
	Arginine hydrochloride	140 mM
	Methionine	5 mM
	TWEEN-20	0.04%

The pH of the stable solution formulation of Example 8 is 5.8.

Example 9


	Ingredients	Concentration

	ET_AR antibody A-1	100 mg/mL
	Sodium citrate
	20 mM
	Arginine hydrochloride	140 mM
	TWEEN-20	0.04%
	EDTA	0.05 mM

The pH of the stable solution formulation of Example 9 is 5.8.

Example 10


	Ingredients	Concentration

	ET_AR antibody A-1	100 mg/mL
	Histidine
	20 mM
	Arginine hydrochloride	140 mM
	TWEEN-20	0.04%
	EDTA	0.05 mM

The pH of the stable solution formulation of Example 10 is 5.8.

13. Methods for Analyzing Stable Pharmaceutical Solution Formulations of an ET_AR Antibody:Size Exclusion High Performance Liquid Chromatography (SEC-HPLC) for Analyzing Monomeric and Aggregated ET_AR Antibodies

SEC-HPLC was used to determine the formation of aggregates (soluble aggregates) of the ET_AR antibody and the loss of its monomeric form. In Agilent 1100 HPLC at 25° C., a TSK-G3000SWx1 high performance SEC column was flushed with 200 mM phosphate buffer (pH 6.8) as a mobile phase till the baseline of the UV absorbance was constant and stable. A stable pharmaceutical solution formulation of the ET_AR antibody at the concentration of 1 to 3 mg/mL (pre-diluted with the mobile phase) was injected in the amount of 50 μL. The sample was eluted with the mobile phase at a flow rate of 0.5 mL/min and the absorbance at UV 280 nm was recorded. After each run, the AUCs of absorbance peaks of the monomer (the main peak), dimers and multimers were calculated, the percentage of the AUC for the main peak versus the total AUC was calculated and reported as the purity of the sample.

Capillary Electrophoresis (CE-SDS) for Analyzing the Purities of Reduced and Non-Reduced ET_AR Antibody Samples

A capillary electrophoresis apparatus (Beckmann MDQP/ACE) was used, and samples were treated with an IgG purity/heterogeneity assay kit (Beckmann) by adding beta-mercaptoethanol to reduced samples or iodoacetamide to non-reduced samples. Beckmann non-coated capillaries were used to separate, and the samples were loaded at a concentration of 1 mg/mL automatically. After finishing loading a sample, separation was performed at 15 kV reverse voltage, and a UV214 nm absorbance time curve was recorded. When the process was finished, the absorption peaks at UV214 nm of the main peak, fragments and aggregates were integrated. For a non-reduced sample, the ratio of the main peak over total area was calculated, which represents the purity of the non-reduced sample. For a reduced sample, the ratio of light and heavy chain peak areas over the total area was calculated, which represents the purity of the reduced sample.

Calcium Flux Detection Method to Determine Inhibitory Activity of an ET_AR Antibody on an ET_AR In Vitro

ET_AR-Aq-#105 cells stably expressing hET_AR-Aequorin were seeded in a 96 well plate at a density of 3.5×10⁴cells/well and 100 μL/well, and the plate was placed at 37° C., 5% CO₂overnight. 100 μL of Colenterazine-h (0.23 μM stock solution) was diluted into 3.2 mL of a DMEM/F12 medium without phenol red. The plate was removed from the incubator, the medium was aspirated, 50 μL/well of diluted Colenterazine-h was added (in the dark), and the plate was placed in the 37° C. incubator for 2 hours. Reference antibody A-1 and test samples were diluted serially, and 50 μL/well of the dilutions were added to the 96 well plate (in the dark). After addition of the samples, the plate was placed in an incubator at 37° C. and 5% CO₂for another 30 min. The fluorescence intensity of each well was read on a microplate reader. The read values of three wells with only DMEM/F12 medium (no phenol red) were the background values, and the rest of the wells were added with 20 nM endothelin-1.

The read data were pasted to Excel for analysis, and the time point of the peak fluorescent intensity was selected as the calculation value. The average of the fluorescence values of the blank controls was obtained, and the average value was then substracted from each original value. After processing, the values of the maximum fluorescence intensities were averaged, and the relative percentage of each well to the average of the maximum response average was calculated finally. Through Prism software, the percentage and concentration of each well were used to calculate IC₅₀values for the reference ET_AR antibody and the test samples, as well as curve fitting correlation coefficients R². The biological activity of a test sample (%)=(IC₅₀of the reference/IC₅₀of the test sample)×100.

14. pH and Buffer Screening:

pH was screened from a pH single factor experiment with antibody A-1 in a 20 mM sodium citrate buffer with pH between 4.7 and 6.3, with a total of 7 experiments (see Table 3) to determine the appearance and A340 absorption of antibody A-1 after 2-hour in a 65° C. water bath. As shown in Table 3, the experimental results indicated that antibody A-1 had relatively good thermal stability within pH 5.0 and 5.7 to 6.3.

TABLE 3

Effect of pH on protein thermal stability at 65° C.

Test	pH	A340	Appearance

1	4.7	0.028	Opalescence and large number of
			floc-like particles
2	5.0	0.073	Floc-like particles
3	5.3	0.451	Large number ofparticles
4	5.5	0.508	Large number of particles
5	5.7	0.218	Large number ofparticles
6	6.0	0.036	Floc-like particles
7	6.3	0.012	Floc-like particles

15. Effect of Concentrations and Types of a Buffer Salt on Protein Stability:

Based on the above pH screening result, further screening experiments were carried out on pH and buffers. The two buffer systems of sodium citrate and histidine were selected, and the experiment was designed with two influencing factors. Two sets of samples were prepared to buffer at 3 different pH values, 20 mM sodium citrate, 200 mM sodium chloride, 0.02% TWEEN-80 at pH 4.7, 5.1, and 5.3; 20 mM histidine, 200 mM sodium chloride, 0.02% TWEEN-80 at pH 5.7, 6.0, and 6.3 (See Table 4). 1 to 6 groups of accelerated degradation experiments were performed, and the concentration of antibody A-1 was kept at 50 mg/mL. The experimental conditions were freeze-thaw: freeze at −20° C., thaw at room temperature, 3 cycles; high temperature: 37° C. for 10 days, 13 days; illumination: 5000 lx, 300 μW/cm², 25° C., 5 days; testing parameters: appearance, visible particles, purity (SEC-HPLC, non-reduced CE-SDS), charge variant.

TABLE 4

Experimental design for buffer salt type and pH screening

	Protein	Sodium	Histidine
Formu-	concentration	citrate	salt	NaCl	TWEEN-80
lation	(mg/mL)	(mM)	(mM)	(mM)	(%)	pH

1	50	20		200	0.02	4.7
2	50	20		200	0.02	5.1
3	50	20		200	0.02	5.3
4	50		20	200	0.02	5.7
5	50		20	200	0.02	6.0
6	50		20	200	0.02	6.3

The results were summarized in Tables 5 to 8. Experimental results indicated that freeze-thaw cycle didn't significantly affect antibody A-1, but based on the results at high temperatures and light exposure, lower pH of sodium citrate resulted readily in the aggregation and loss of purity. Antibody A-1 is relatively sensitive to light, especially in term of charge variant, and after 5 days of light exposure, the main peak dropped significantly and the basic peak decreased.Only formulation 4 changed little, followed by formulation 5. Therefore,formulation 4 was selected as the formulation for the next protectant screening.

TABLE 5

Appearance inspection results of formulation samples

		High	High
		temperature	temperature	Freeze-and-	Illumination
Formulation
	0day	10 days	13 days	thaw	5days

1	Colorless and	Slight	Apparent	Colorless	Opalescence
	clear	opalescence	opalescence	and clear	No visible
	No visible	No visible	No visible	No visible	particles
	particles	particles	particles	particles
2	Colorless	Colorless	Colorless	Colorless	Opalescence
	and clear	and clear	and clear	and clear	No visible
	No visible	No visible	No visible	No visible	particles
	particles	particles	particles	particles
3	Colorless	Colorless	Colorless	Colorless	Opalescence
	and clear	and clear	and clear	and clear	No visible
	No visible	No visible	No visible	No visible	particles
	particles	particles	particles	particles
4	Colorless	Colorless	Colorless	Colorless	Opalescence
	and clear	and clear	and clear	and clear	and slight
	No visible	No visible	No visible	No visible	yellow
	particles	particles	particles	particles	No visible
					particles
5	Colorless	Colorless	Colorless	Colorless	Slight
	and clear	and clear	and clear	and clear	yellow
	No visible	No visible	No visible	No visible	No visible
	particles	particles	particles	particles	particles
6	Colorless	Colorless	Colorless	Colorless	Slight
	and clear	and clear	and clear	and clear	yellow
	No visible	No visible	No visible	No visible	No visible
	particles	particles	particles	particles	particles

TABLE 6

SEC purity (%) test results of formulation samples

		High	High	Freeze-
		temperature	temperature	and-	Illumination
Formulation
	0day	10 days	13 days	thaw	5days

1	98.05	86.32	84.60	98.01	92.11
2	98.01	96.56	95.78	97.95	92.84
3	97.99	97.56	96.72	97.93	93.39
4	98.05	97.85	97.05	98.02	95.12
5	98.04	97.45	97.08	98.02	95.08
6	98.03	97.94	97.16	98.01	94.43

TABLE 7

Non-reduced CE-SDS purity (%) test results of formulation samples

		High	High
		temperature	temperature	Freeze-and-
Formulation	0day	10 days	13days	thaw

1	96.50	93.71	92.59	95.80
2	96.78	94.77	89.90	95.81
3	96.40	95.59	95.47	95.76
4	96.20	95.55	95.47	95.77
5	96.12	95.55	95.84	96.13
6	96.22	95.61	95.89	95.21

TABLE 8

Changes of charge variant main peak (%) of formulation samples

		High	High
		temperature	temperature	Freeze-and-
Formulation	0day	10 days	13days	thaw

1	59.80	62.53	62.57	58.82
2	59.53	62.42	63.84	59.08
3	59.88	62.64	63.30	58.90
4	59.49	62.09	60.42	58.73
5	59.56	61.17	61.13	59.23
6	60.54	60.76	60.89	59.07

16. Protectant Screening:Experimental Plan

Two groups of experiments were performed. Six protectants were tested in the first group of experiments, and they are 5% sucrose, 2% mannitol, 2% sorbitol, 100 mM NaCl, 140 mM arginine, and 150 mM proline. In this group, the protein concentration of antibody A-1 was 60 mg/mL, the concentration of histidine as a buffer salt was 20 mM, TWEEN-80 concentration was 0.02%, and pH was 5.8. The experimental conditions were freeze-thaw: freeze at −20° C., thaw at room temperature, 5 cycles; high temperature: 40° C. for 10 days, 13 days; illumination: 5000 lx, 300 μW/cm², 25° C., 5 days; shaking: 300 rpm, room temperature for 3 days in the dark; testing parameters: appearance, visible particles, purity (SEC-HPLC, non-reduced CE-SDS), charge variant. The design plan is shown in Table 9.

TABLE 9

Experimental design for protectant screening

	NaCl	Sucrose	Mannitol	Sorbitol	Arginine	Proline
Formulation	(mM)	(%)	(%)	(%)	(mM)	(mM)

7	100	5	—	—	—	—
8	100	—	2	—	—	—
9	100	—	—	2	—	—
10	—	—	—	—	140	—
11	—	—	—	—	—	150
12	100	—	2	—	—	—

The second group of experiments were performed based on the first group of experiments, and sodium citrate was selected as the buffer system. The concentration of sodium citrate was 20 mM, pH was 5.8, and the concentration of antibody A-1 was about 30 mg/mL. In the F1 formulation, arginine was replaced with arginine hydrochloride, and its concentration was 140 mM. Further, the experiment for the selection of a protectant was performed, and conditions of high temperature and illumination were modified to 40° C./2 watts, 1 month, 5000 lx, 0 day, 2 days, 5 days, 10 days. The design plan is shown in Table 10.

TABLE 10

Protectant screening design table

For-	Protein	So-
mu-	Conc.	dium	Arginine			Sor-	Tween-
la-	(mg/	citrate	HCl	Sucrose	Mannitol	bitol	80
tion	mL)	(mM)	(mM)	(%)	(%)	(%)	(%)	pH

F1	26.4	20	140	—	—	—	0.04	5.8
F2	30.2	20	—	5	—	—	0.04	5.8
F3	29.4	20	—	—	5	—	0.04	5.8
F4	29.8	20	—	—	—	5	0.04	5.8

Experimental Results

The results of the first group of experiments showed that, after 5 days of illumination, the color of 6 formulation samples all turned yellow to different degrees. The results of SEC-HPLC indicated, in comparison with other protectants, arginine was more effective in reducing aggregate formation. (Table 11).

For 7, 13 days athigh temperature 40° C.: the results of SEC-HPLC showed, in comparison with the monomer purity (98%) at 0 day, there was no significant difference in the decrease of monomer in each formulation, and there was even less reduction of purity for the formulations containing sucrose, arginine and proline. The results are shown in Table 12 below.

TABLE 11

Test results of formulation samples after illumination

For-			Aggre-		Mono-	Frag-
mula-			gate	Dimer	mer	ment
tion	Appeamnce	Visible particles	(%)	(%)	(%)	(%)

7	Slight yellow	No visible particles	0.66	4.92	93.66	0.76
8	Slight yellow	No visible particles	0.61	4.77	93.97	0.65
9	Slight yellow	No visible particles	0.62	4.79	93.95	0.64
10	Slight yellow	No visible particles	0.44	3.90	95.15	0.51
11	Slight yellow	No visible particles	0.73	5.07	93.60	0.61
12	Slight yellow	No visible particles	0.66	4.90	93.81	0.63

TABLE 12

Test results of formulation samples after high temperature

					Charge
					variant
			Visible	Monomer	main peak
Formulation	Day	Appearance	particle	(%)	ratio (%)

7	7	Colorless	No visible	97.88	65.44
		andclear	particles
8	7	Colorless	No visible	97.50	61.50
		andclear	particles
9	7	Colorless	No visible	97.44	63.14
		andclear	particles
10	7	Colorless	No visible	97.77	63.50
		and clear	particles
11	7	Colorless	No visible	97.83	65.24
		andclear	particles
12	7	Colorless	No visible	97.48	63.52
		andclear	particles
7	13	Colorless	No visible	97.40	65.33
		andclear	particles
8	13	Slight	No visible	97.31	61.32
		opalescent	particles
9	13	Colorless	No visible	97.15	64.84
		andclear	particles
10	13	Colorless	No visible	97.34	66.03
		and clear	particles
11	13	Slight	No visible	97.34	65.44
		opalescent	particles
12	13	Slight	No visible	97.25	65.70
		opalescent	particles

The test results of shaking and freeze-thaw (see Table 13) indicated that, in comparison with 0 day, there was no significant difference for the aggregate and charge variant.

In the second group of experiments, the sodium citrate was used as the buffer, and the results indicates that, after high temperature and illumination, the formulation of antibody A-1 showed slight opalescence (see Table 14). Comparing the effects of several protectants, we considered arginine hydrochloride the best in preserving the purity of antibody A-1 (see Table 15). The illumination induced significant change of charge variants (see Table 16), therefore, it was recommended to store antibody A-1 in the dark.

TABLE 13

Test results of formulation samples after shaking and freeze-thaw

For-

SEC purity (%)

Ratio of charge variant

mu-

Freeze-

main peak (%)

lation	0day	Shaking	thaw		0 day	Shaking	Freeze-thaw

7	97.98	98.03	97.97	60.02	60.24	58.60
8	97.95	98.00	97.88	59.72	59.97	59.07
9	97.99	98.03	97.95	59.51	59.71	58.92
10	98.03	98.08	97.96	59.57	59.65	59.13
11	98.00	98.01	97.97	59.44	60.40	59.22
12	97.99	98.02	97.92	59.39	59.58	58.95

TABLE 14

Change of appearance and visible particles of formulation samples

Appearance

		Illumination
Formulation

	0day	10days	40° C., 1 month

F1	Clear	Slight opalescence	Slight opalescence
	No visible	No visible particles	No visible particles
	particles
F2	Clear	Slight opalescence	Slight opalescence
	No visible	No visible particles	No visible particles
	particles
F3	Clear	Slight opalescence	Slight opalescence
	No visible	No visible particles	No visible particles
	particles
F4	Clear	Slight opalescence	Slight opalescence
	No visible	No visible particles	No visible particles
	particles

TABLE 15

Test results of SEC purities (%) of formulation samples

							High	High
							tem-	tem-
							per-	per-

For-

Illumination

ature

mu-			Freeze-	2	5	10	2	1
lation	0 day	Shaking	thaw	days	days	days	weeks	month

F1	98.54	98.60	98.54	98.36	98.13	—	98.53	98.53
F2	98.40	98.30	98.44	98.27	97.94	97.83	97.92	96.2
F3	98.36	98.26	96.32	97.96	97.96	97.22	97.94	95.85
F4	98.40	98.30	98.44	98.18	97.83	97.63	97.72	94.92

Note:
the sample of illumination for 10 days was left out by mistake, therefore, the SEC purity and charge variant data of the sample was not available.

TABLE 16

Test results of charge variant main peak (%) of formulation samples

mula-			Freeze-	2	5	10	ature	ature
tion	0 day	Shaking	thaw	days	days	days		2weeks	1 month

F1	70.40	72.08	72.97	60.34	48.26	—	59.64	56.41
F2	69.64	72.86	72.81	67.96	49.51	47.59	56.86	63.79
F3	72.19	72.71	73.84	65.12	49.56	51.03	69.05	61.88
F4	70.24	72.82	70.2	63.98	49.04	49.54	53.90	61.22

17. The Experiment on the Factors Affecting Antioxidants:Experimental Plan

The experiment was to evaluate the protective effect of 0.0187 mg/mL EDTA, and two buffers were selected, 20 mM histidine salt and 20 mM sodium citrate with 0.02% and 0.1% of Tween-80 (Table 17). The concentration of antibody A-1 was 60 mg/mL, arginine hydrochloride was 140 mM, and pH was 5.8. The three formulation samples were subject to accelerated degradation experiment, and the experimental condition was illumination: 5000 lx, 300 μW/cm², 25° C., 3 days, 6 days; the test items: appearance, visible particles, purity (SEC-HPLC), and charge variant.

TABLE 17

Antioxidant screening table

	Histidine salt	Sodium citrate	EDTA	Tween-80
Formulation	(mM)	(mM)	(mg/mL)	(%)

13	20	—	0.0187	0.02
14	20	—	—	0.1
15	—	20	—	0.02

Based on the above experiment, methionine was added as a screening antioxidant, and the detailed plan was in Table 18. The experiment conditions were:high temperature 40° C. for 2 weeks, 1 month;illumination 5000 lx for 0 day, 2 days, 5 days, 10 days.

TABLE 18

Methionine formulation screening table

			Arginine
For-	Con-	Sodium	hydrochloride
mu-	centration	citrate	(%)	Methionine	Tween-
lation	(mg/mL)	(mM)	(mM)	(mM)	80	pH

F1-M	~50	20	140	—	0.04	5.8
F2-M	~50	20	140	5	0.04	5.8
F3-M	~50	20	140	10	0.04	5.8

Experimental Results

Based on the results of two groups of experiments, neither of the two protectants affects antibody A-1 significantly. No difference was observed in the different concentrations of Tween used (Table 19, Table 20, Table 21, Table 22), but when using histidine as the formulation buffer salt, the formulation turned yellow after illumination, therefore, sodium citrate is a better choice as the formulation buffer salt. After three days of destruction with illumination, the SEC-HPLC peaks of formulation samples 13 to 15 decreased with no notable difference between them. The peak of the 3-day formulation sample is the same as 0 day's in the dark. After 6 days of destruction by illumination, the peak of sample 13 showed even more reduction, whilesample 14 and 15 showed no further reduction. The peak of the 6-day formulation sample is the same as 0 day's in the dark.

TABLE 19

Test results of formulation samples after illumination

				SEC
				purity
Formulation	Condition	Appearance	Visible particle	(%)

13	Illumination	Slightly yellow	No visible	97.11
	3days		particles
14	Illumination	Very slightly yellow	No visible	97.27
	3 days		particles
15	Illumination	Opalescence	No visible	96.97
	3 days		particles
13	Illumination	Clear and colorless	No visible	98.07
	3 days		particles
15	Illumination	Clear and colorless	No visible	98.05
	3 days		particles
13	Illumination	Slightly yellow	Tiny particles	96.12
	6days
14	Illumination	Slightly yellow	Tiny particles	96.41
	6 days
15	Illumination	Opalescence	Tiny particles	96.24
	6 days
13	Illumination	Clear and colorless	No visible	97.97
	6 days		particles
15	Illumination	Clear and colorless	No visible	98.08
	6 days		particles

TABLE 20

Appearance, visible particles and purity change of formulation
samples afterhigh temperature 40° C.

For-

SEC purity (%)

Appearance

mu-		1	1		2
lation	0day	week	month		0day	weeks	1 month

F1-M	98.51	98.65	97.30	Slight	Opalescence	Opalescence
				opalescence	No visible	No visible
				No visible	particles	particles
				particles
F2-M	98.50	98.67	97.37	Slight	Opalescence	Opalescence
				opalescence	No visible	No visible
				No visible	particles	particles
				particles
F3-M	98.53	98.66	97.53	Slight	Opalescence	Opalescence
				opalescence	No visible	No visible
				No visible	particles	particles
				particles

TABLE 21

Test results of the SEC purity (%) of formulation samples
after illumination and high temperature

	0day	2 days	5days	10days	2weeks	1 month

F1-M	98.51	98.23	97.95	97.38	98.65	97.30
F2-M	98.50	98.23	97.98	97.75	98.67	97.37
F3-M	98.53	98.28	98.03	97.85	98.66	97.53

TABLE 22

Test results of the charge variant main peak (%) of formulation samples
after illumination and high temperature

	0day	2 days	5days	10days	2weeks	1 month

F1-M	68.83	46.82	47.23	46.39	64.13	55.13
F2-M	70.16	45.53	48.85	45.87	62.43	57.05
F3-M	75.67	62.50	49.97	44.06	64.54	58.48

18. Long-Term and Accelerated Stability Study at Different Protein Concentrations:Experimental Plan

After determining the initial formulation, we also did long-term and acceleration stability studies on the antibody A-1 at different concentrations. We set the antibody concentrations at 25, 50, and 100 mg/mL, and used the defined formulation to pursue long-term (4° C., 0 day, 1 month, 2 months, 3 months, 6 months, 9 months) and acceleration (25° C., 0 day, 1 month, 2 months, 3 months, 6 months, 9 months) stability studies. The test items are: protein concentration, appearance, visible particle, pH, purity (SEC-HPLC, non-reduced CE-SDS), charge variant, bioactivity. The design plan is shown in Table 23 below.

TABLE 23

Formulation design table for antibody A-1 at different concentrations

	Protein	Sodium	Arginine
	concentration	citrate	hydrochloride	Tween-80
Formulation	(mg/mL)	(mM)	(mM)	(%)	pH

F11	26.1	20	140	0.04	5.8
F12	53.9	20	140	0.04	5.8
F13	103.1	20	140	0.04	5.8

Experimental Results

From appearance, as the protein concentration increased, the opalescence increased, and it's easier for the formulation samples to turn yellow at high concentration of the antibody (see Table 24). But after nine-month of long-term and acceleration stability test, the formulation sample was still clear and free of visible particles, meeting the requirement of injection. There was no significant change of the protein concentration and pH during the study (see Table 25 and Table 26).

The purity test result indicated, the SEC and CE-SDS purity of antibody A-1 decreased as the time passed and as the concentration increased. The CE-SDS purity of the samples decreased slightly more (see Table 27, Table 28 and Table 29). But after 9-month of stability test, the purity of the product still met the corresponding quality standards and, and the change of purity was within the acceptable range.

The test result of charge variants indicated (see Table 30), the aggregates and acidic/basic charge variants increased as the protein concentration of antibody A-1 increased, and the stability at lower protein concentration is better. However, judging from the shape of the peaks, there is not much difference at the three concentrations, and the trend was consistent. Bioactivity test of the 3-month samples indicated the bioactivity was relatively stable, as shown inFIG. 6 andFIG. 7. Based on the above results, the protein is stable in this formulation for at least 18 months.

TABLE 24

Appearance change of formulation samples during 0-9 months

Formulation	Temp.	0day	1month	2months	3months	6months	9months

F11
	0° C.	Clear	Clear	Clear	Clear	Slight	Slight
						opalescence	opalescence
F12
	0° C.	Clear	Clear	Slight	Slight	Slight	Slight
				opalescence	opalescence	opalescence	opalescence
F13
	0° C.	Slight	Slight	Opalescence	Slight	Slight	Slight
		yellow	yellow		yellow and	yellow and	yellow and
					opalescence	opalescence	opalescence
F11	25° C.	Clear	Clear	Clear	Clear	Slight	Slight
						opalescence	opalescence
F12	25° C.	Clear	Clear	Slight	Slight	Slight	Slight
				opalescence	opalescence	opalescence	opalescence
F13	25° C.	Slight	Slight	Opalescence	Slight	Slight	Slight
		yellow	yellow		yellow and	yellow and	yellow and
					opalescence	opalescence	opalescence

TABLE 25

Test results of protein concentrations (mg/mL) of formulation
samples in long-term accelerated stability study

Formu-			1	2	3	6	9
lations	Temp.	0 day	month	months	months	months	months

F11

	0° C.	26.1	25.7	26.5	27.0	28.0	24.9
F12	0° C.	53.9	54.0	51.6	51.2	54.5	48.4
F13	0° C.	103.1	97.2	101.2	106.7	114.9	94.1
F11	25° C.	26.1	27.7	26.1	27.4	29.5	25.3
F12	25° C.	53.9	51.5	51.7	57.6	58.1	54.3
F13	25° C.	103.1	106.1	99.9	110.1	115.7	94.1

TABLE 26

Test results of pH of formulation samples in a long-term
accelerated stability study

Formu-		0	1	2	3	6	9
lations	Temp.	day	month	months	months	months	months

F11
	0° C.	5.89	5.86	5.88	5.87	5.86	5.84
F12	0° C.	5.89	5.86	5.86	5.84	5.86	5.83
F13	0° C.	5.91	5.87	5.88	5.83	5.87	5.86
F11	25° C.	5.89	5.85	5.87	5.96	5.83	5.84
F12	25° C.	5.89	5.86	5.86	5..83	5.88	5.86
F13	25° C.	5.91	5.86	5.88	5.84	5.89	5.87

TABLE 27

Test results of SEC purity (%) of formulation samples in a
long-term accelerated stability study

Formu-		0	1	2	3	6	9
lations	Temp.	day	month	months	months	months	months

F11
	0° C.	98.6	98.7	98.7	98.7	98.6	98.7
F12	0° C.	98.6	98.6	98.6	98.7	98.7	98.6
F13	0° C.	98.5	98.6	98.5	98.6	98.6	98.5
F11	25° C.	98.6	98.7	98.7	99.0	98.6	98.1
F12	25° C.	98.6	98.6	98.6	98.8	98.5	98.2
F13	25° C.	98.5	98.5	98.5	98.6	98.1	97.9

TABLE 28

Test results of the non-reduced CE-SDS purity (%) of formulation
samples in a long-term accelerated stability study

Formu-			1	2	3	6	9
lations	Temperature		0 day	month	months	months	months	months

F11
	0° C.	97.23	98.26	97.86	97.75	97.88	96.36
F12	0° C.	97.17	98.24	97.78	97.77	96.84	96.01
F13	0° C.	97.06	97.9	97.89	97.39	97.07	96.16
F11	25° C.	97.23	97.42	97.63	96.34	96.68	94.94
F12	25° C.	97.17	97.66	97.51	97.44	96.59	94.80
F13	25° C.	97.06	97.47	97.44	97.42	96.77	94.45

TABLE 29

Test results of reduced CE-SDS purity (%) of formulation
samples in a long-termaccelerated stability study

		3	6	9
Formulations	Temperature	months	months	months

F11

	0° C.	100	100	100
F12	0° C.	100	100	100
F13	0° C.	100	100	99.98
F11	25° C.	100	99.83	99.91
F12	25° C.	99.56	100	99.38
F13	25° C.	99.12	98.49	96.07

TABLE 30

Test results of the charge variant main peak (%) of formulation
samples in a long-term accelerated stability study

Formu-			1	2	3	6	9
lations	Temperature		0 day	month	months	months	months	months

F11
	0° C.	74.97	71.40	66.28	72.80	72.30	80.68
F12	0° C.	74.74	71.30	71.01	71.40	67.96	77.81
F13	0° C.	75.01	71.40	65.95	72.40	69.1	77.13
F11	25° C.	74.97	74.48	70.22	66.64	65.69	69.22
F12	25° C.	74.74	75.96	65.47	68.17	65.36	69.26
F13	25° C.	75.01	74.30	69.18	66.97	63.15	78.5

The formulation of antibody A-1 (20 mM sodium citrate, 140 mM arginine hydrochloride, 0.04% TWEEN-80, pH 5.8) was tested at 3 different antibody concentrations in long-term and accelerated stability studies. After 9 months, regardless of acceleration and long-term stability studies, the quality of the protein still met the quality standards set. Especially after 9 months of long-term storage, the purity of antibody A-1 remained above 98%.

The above embodiments are provided to fully disclose and explain how to make and use the claimed embodiments to one of ordinary skill in the art, and they are not meant to limit the scope of this disclosure. Modifications obvious to those skilled in the art are within the scope of the claims herein. All the publications, patents and patent applications cited in the specifications were incorporated herein as references, just as each of them was specifically and independently incorporated herein as a reference.