Expression of HLA system antigens on placenta.
The levels of HLA-A and -B antigens expressed by placenta have been assessed relative to parental and other A and B antigen types that were not shared by the foetus. A purified preparation of placenta plasma membrane was used to estimate the antigen activities. The results indicate that maternally and paternally inherited A and B antigen activities and beta2-microglobulin are expressed to similar extents but at much lower levels than in spleen lymphocytes (less than 5%). The possibility that the amounts detected were caused by contamination with blood or maternal tissue was ruled out. The low levels of A and B antigens may account for the lack of a cellular immune response to the other polymorphic cell surface antigens of the trophoblast. No evidence was obtained for the expression of a significant level of Ia antigens.
D002462:Cell Membrane / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006680:HLA Antigens / Q000032:analysis*; D006649:Histocompatibility Antigens / Q000032:analysis*; D006801:Humans; D010920:Placenta / Q000276:immunology*; D011247:Pregnancy; D014327:Trophoblasts / Q000276:immunology; D001613:beta 2-Microglobulin / Q000032:analysis
D006680:HLA Antigens; D006649:Histocompatibility Antigens; D001613:beta 2-Microglobulin