Monoclonal antibodies to baboon syncytiotrophoblast and cytotrophoblast.

Three monoclonal antibodies (BM2, BM3 and BM4) were obtained from two hybridomas produced after murine immunization with total placental cell dispersion obtained from animals at day 33 of gestation. Immunohistochemical studies showed that antigens recognised by these three antibodies were located on villous trophoblast of fixed placental sections at day 33 of pregnancy. Other fixed normal baboon tissues tested were non-reactive with these antibodies. Monoclonal antibody BM2 was found to stain villous cytotrophoblast; BM3 and BM4 reacted with syncytiotrophoblast but with different staining characteristics. Immunoblot studies showed that BM2, BM3 and BM4 antibodies recognized antigens corresponding to 30.9, 31.3 and 42.3 kDa, respectively.