[The differentiation antigen of trophoblast expressed on trophoblastic neoplasms (choriocarcinoma and hydatidiform mole) detected by monoclonal antibodies].

To analyse the differentiation and malignant transformation of human trophoblasts, attempts were made to establish monoclonal antibodies (MoAbs) that react with cells at a certain stage of the trophoblast differentiation process. Two MoAbs, TM7-3 and TM3-8, were obtained by immunizing BALB/c mice with a human choriocarcinoma cell line, BeWo. In the cellular radioimmunoassay with 125I-labelled F(ab')2 of goat anti-mouse IgG, they reacted with nine out of ten choriocarcinoma cell lines and five of sixteen non-choriocarcinoma cell lines but not with twenty-six lymphoblastoid cell lines tested. Immunofluorescence and immunoperoxidase stainings showed that these MoAbs reacted predominantly with cytotrophoblast-like, but not syncytiotrophoblast-like components in the tissue of choriocarcinoma or hydatidiform mole, in the normal chorionic villi, cytotrophoblasts were very weakly positive but syncytiotrophoblasts were negative, and in a variety of normal tissues tested, only a part of the urinary tubules of kidney and the ducts of pancreas reacted to these MoAbs. These results suggest that TM7-3 and TM3-8 detect a differentiation antigen of human trophoblasts, which appears to increase with the malignant transformation of cytotrophoblasts. Thus, TM7-3 and TM3-8 may be useful in the study of human trophoblast differentiation.