Cross-reactivity of monoclonal antibodies directed against lymphocyte markers with trophoblast cells of normal placenta, hydatidiform mole, and gestational choriocarcinoma.

The current study was undertaken to characterize the expression of trophoblast-lymphocyte cross-reactive antigens on normal, molar, and malignant trophoblast. A panel of monoclonal antibodies directed against lymphoid cell markers were tested in immunofluorescence assay on cryostat sections of placenta and mole and on monolayers of choriocarcinoma cells. NKH-1, a monoclonal antibody to natural killer cells, reacted with both molar and placental villous trophoblast and with two choriocarcinoma cell lines. NKH-2, a monoclonal antibody reactive with a subset of natural killer cells, did not react with placental villous trophoblast but reacted with molar villous trophoblast in three of five moles tested and with both choriocarcinoma cell lines. B5, a monoclonal antibody which reacts with activated B cells, reacted with both choriocarcinoma cell lines but did not react with normal placental or molar trophoblast. MY7, a monoclonal antibody to myeloid colony-forming cells, reacted with only one of the choriocarcinoma cell lines. Trophoblast-lymphocyte cross-reactive antigens may be important in the immunobiology of gestational trophoblastic disease by modulating interactions between the trophoblast and the maternal immune system.