Pore-forming protein (perforin) is a cytolytic molecule located in the granules of the cells mediating cell cytotoxicity reactions. Cytotoxic T- lymphocyte effectors can belong to class I or class II major histocompatibility complex-restricted subpopulations (CD8+P+ and CD4+P+ phenotype) or natural killer cells (CD56+CD16+P+ and CD56+CD16-P+ phenotype). The number of perforin-expressing lymphocytes in the metrial gland of the murine pregnancy decidua is higher than observed in any other tissue infiltrated by cytotoxic cells during pathological processes (viral, autoimmune, tumor, or allogeneic transplant rejection). It has been proposed that the function of perforin-positive cells is to restrict the trophoblast invasion during the first trimester of pregnancy, intercepting and killing aberrant placental and embryonic cells and preventing maternal-fetal viral transmission. This is supported by the observation thai molecules capable of inducing cell apoptosis colocalize with perforin in the cytoplasmic granules of CD56+ decidual cells. Our immunohistochemical analysis of perforin expressing lymphocytes in both decidua basalis and decidua parietalis showed a higher number of positive cells in decidua parietalis in the vicinity of noninvasive trophoblast than in decidua basalis. By using monoclonal antibody (mouse, IgG2b) antihuman perforin and a method developed in our laboratory for simultaneous detection of perforin and cell surface antigens by flow cytometric analysis, we came to the following conclusions: (a) The percentage of perforin+ cells in the suspension of decidual lymphocytes is two times higher than in peripheral blood lymphocytes; (b) The prevalent phenotype of decidual perforin+ cells is CD3-CD2+CD16-CD56(bright)P(bright+); (c) In spite of much higher content of perforin the cytotoxicity of decidual natural killer cells is far lower than that of the PBL; (d) There are no classical cytotoxic T lymphocytes (CD3+CD8+P+); and (e) Cells with the potential to mediate antibody-dependent cytotoxicity are very few (98% of CD56+ cells are CD16-).
|Original language||English (US)|
|Number of pages||6|
|State||Published - Jan 1 1995|
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