| Kurloff cell | |
|---|---|
 Kurloff cell and a lymphocyte in a Guinea pig | |
| Details | |
| Location | blood andorgans ofguinea pigs andcapybara |
| Anatomical terms of microanatomy | |
Kurloff cells (also known asFoà-Kurloff cells[1]) were described as mononuclear cells in the peripheral blood and organs of theguinea pig,capybara,[2]paca,agouti andcavie.[3] The Kurloff cell contains a characteristic proteoglycan-containing inclusion body. In the guinea pig, Kurloff cells are more numerous in the adult female than the adult male.[4] A marked increase in the number of circulating Kurloff cells is present in the peripheral blood during pregnancy and after estrogen treatment in male and female animals.[1] A relatively smaller number of cells take place in immature, non-pregnant, and non-estrogen-treated animals. The exact function of Kurloff cells remains unknown, but it has some of the characteristics of bothmonocytes andlymphocytes. In guinea-pigs, it has been proposed that Kurloff cells mainly involve in the function of the immune system, such as acting as anatural killer cell and preventing damage to thetrophoblast by maternal defensive cells. Also, Kurloff cells present antibody-dependent cytotoxic activityin vitro.[5][6][7]
The structure of Kurloff cell was identified usinglight microscopy andperiodic-acid Schiff staining. The Kurloff cell has an egg shape and the axis of the cell varies from 8 to 12 μm in length, and 10-25 μm in diameter.[4][8] The inclusion body, which is round in shape and 1-8 μm in diameter, occupies most of the cell'scytoplasm.[4] Also, the inclusion body resembles alymphocyte. The nucleus of Kurloff cell is sickle-shaped and is pushed toward the periphery of the cell by the inclusion body.[2]
Inthymus andspleen, Kurloff cells are categorized depending on the size and the number ofinclusion bodies within cells. The cells with small and medium-sized inclusions are present when the density ofthymocytes is low. On the other hand, cells with large inclusion bodies were first observed among low-density cells. Over time, they are found where the density ofthymocytes is high.[9]
In pregnant and estrogen-treated male and female guinea pigs, clumps of Kurloff cells containing inclusion bodies of different sizes are present in large numbers in stromal tissue of thethymus andbone marrows, and the pulp cords of thespleen. In the thymus, clumps of Kurloff cells are occasionally seen at the cortico-medullary junction, scattered single cells are seen in the cortex, and numerous Kurloff cells are spotted inlymphatics andvenules.[4][8] In the spleen, Kurloff cells are absent in the lymphoid tissue of the white pulp, whereas there are large numbers in the red pulp.[4] In the vertebralbone marrow, Kurloff cells are seen scattered as single cells and in clumps in random pattern among thehematopoietic cells in thestroma.[4][8] Besides, theveins andlymphatic vessels of these tissues contain a significantly large number of Kurloff cells relative to the numbers in thearterial blood supply.[8] It has been suggested that Kurloff cells might be produced at these sites. A small amount of Kurloff cells are observed withinlymph nodes, and those which are present are in sinuses andblood vessels. During pregnancy and after treatment, a large number of Kurloff cells circulated in the blood.[10] At the placenta of a pregnant guinea pig, Kurloff cells are more concentrated at the vascular channels of the labyrinth than theplasmodial spongy zone[4]
In guinea pig, the Kurloff cells have some characteristics ofmonocytes andlymphocytes. The first characteristic that Kurloff cells share with monocytes is the presence in the blood and organ but absence from thespleen white pulp, thymus parenchyma, and lymph node follicles. The second shared characteristic is that the Kurloff cell has a receptor for cytophilicimmunoglobin. On the other hand, Kurloff cells have many lymphocytic features such as it does not containlysosomes orphagosomes,[4] lack of nonspecificesterase activity,[11] andphagocytic capacity, and last, the Kurloff cell with the early inclusion body possesses a lymphocytemorphology. The results of antibody-dependent cellular cytotoxicity assay[7][12] on guineas-pig Kurloff cells strongly indicate an immunological role of the cells as thenatural killer cell. The data also suggest that the Kurloff cell is probably the predominant cytotoxic line in guinea piglymphocyte composition, and different level of killer cell activities depends mostly on varying degrees of Kurloff cell contamination.
The Kurloff cells were suggested to have an impact on the immunological status of the guinea-pig placenta. The fate of cells in pregnant guineas pig has been studied byimmunofluorescent methods, including an antiserum against the isolatedmucoprotein of the inclusion body. The satisfactory staining of the inclusion particle was extracted from thespleen andthymus.Immunofluorescence results showed that during pregnancy circulating Kurloff cells release their inclusion particles inside thetrophoblast.[13] In the placenta, the Kurloff cell was occasionally surrounded by a cloud of tiny droplets of material, which gives a similar staining result as the inclusion particles. That material was frequently observed displaying on the luminal surface of the inner placenta compartment. It was obvious that the Kurloff cell must have a role during pregnancy in the guinea-pig because of a significant increase in the number of these cells in the blood and tissues. The inclusion material has been proved to prevent immunological damage to target cells when purified.[6] Studies were done on the effect of extracted inclusion body material in purified form, on inflammatory cells in vitro.[5][6] The results showed marked toxic effects on macrophages with first clumping follow by cell death. The evidence suggests that Kurloff cells may play a part in preventing immunological damage to the trophoblast by maternal defensive cells.
{{citation}}: CS1 maint: work parameter with ISBN (link)