[HLA antigen on the trophoblast of normal pregnancy].
The mechanism of fetal survival as a semiallograft in the uterus remains to be clarified. In this context, the expression of HLA antigen on the trophoblast which stands between the mother and the fetus is the main problem, because HLA antigen plays an important role in immunological reaction to an allograft. For this purpose, 41 pregnant uteri (6-18 weeks of gestation) were examined immunohistochemically (avidin-biotin-peroxidase complex method) using monoclonal antibodies to HLA antigens. Troma 1, a rat monoclonal antibody, was used as a trophoblast marker in immunohistochemical studies. The results were as follows: HLA-A,B,C is not expressed on syncytiotrophoblast and villous cytotrophoblast. HLA-A,B,C is expressed on nonvillous cytotrophoblast which exists in cytotrophoblastic cell column, cytotrophoblastic shell, and endometrium. HLA-DR is not expressed on any trophoblast. The absence of HLA antigen on syncytiotrophoblast and villous cytotrophoblast seems to be essential for the survival of the fetus. But it is proved that some trophoblasts express HLA-A,B,C on their cell surface and they are adjacent to endometrial cells or maternal blood. From these findings, it seems that fetal HLA antigen might be recognized by the mother and there might be an exquisite immune escape mechanism in decidua.
D000911:Antibodies, Monoclonal / Q000276:immunology; D005260:Female; D005333:Fetus / Q000276:immunology; D005865:Gestational Age; D006680:HLA Antigens / Q000032:analysis*; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens; D006801:Humans; D007124:Immunoenzyme Techniques; D011247:Pregnancy; D014327:Trophoblasts / Q000276:immunology*
D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D015236:HLA-C Antigens