Common Antigenic Determinants on Human Melanoma, Glioma, Neuroblastoma, and Sarcoma Cells Defined with Monoclonal Antibodies1

Antigenic determinants that are common to melanomas, gliomas, neuroblastomas, and sarcomas but that are minimally or not detectably expressed by adult tissues were defined with monoclonal antibodies. Quantitative absorption of monoclonal antibody (Ab 165) with adult tissues followed by testing on antigen-positive UCLA-SO-M14 melanoma cells did not dem onstrate antigenic determinant (Ag 165) in brain, lung, liver, kidney, intestine, adrenal, and muscle. Absorption of Ab 376 demonstrated Ag 376 in adult lung but minimal or no antigen in other tissues. Both antigens were associated with a variety of fetal tissues. Assessment of 28 human tumor cell lines with the 131l-staphylococcal Protein A-binding test demonstrated that Ab 165 reacted strongly with melanomas and gliomas and weakly with sarcomas. Ab 376 reacted strongly with melano mas, gliomas, neuroblastomas, and sarcomas. Neither of these antibodies reacted appreciably with carcinoma or teratoma cell lines. Absorption of Ab 165 and Ab 376 with noncultured tumors demonstrated that melanomas, sarcomas, and neurob lastomas can have greater quantities of these antigens in vivo than do normal adult tissues. Qualitative and quantitative anti genic heterogeneity within positive classes of tumors was dem onstrated for both cultured and noncultured tumors. The dif ferences in antigen expression in vivo between normal and neoplastic cells suggest potential value for these antibodies in immunodiagnosis and possibly immunotherapy.