[Analysis of HLA-DR antigen expression on choriocarcinoma]

A choriocarcinoma and four choriocarcinoma cell lines were selected to investigate whether or not HLA-DR antigen is expressed on the cell surface of a choriocarcinoma which is regarded genetically as an allogeneic grafted tumor. Choriocarcinoma tissue was obtained from a uterus which was removed surgically, was prepared for immunoperoxidase staining method using monoclonal antibodies (7B6 and 8B3: They recognize monomorphic determinants on the HLA-DR antigen), and choriocarcinoma cell lines (BeWo, GCH, ENAMI and SCH) were prepared for inhibition test with radioimmunoassay using monoclonal antibodies (7B6 and Kop.). By immunoperoxidase staining, no HLA-DR positive choriocarcinoma cell (or myometrial cell) was demonstrated, although several cells of the uterine side, which contact the invasion of the choriocarcinoma showed positive staining. In an inhibition test, none of the four cell lines showed any inhibition. The present results suggested that HLA-DR antigen is not found in choriocarcinoma.