Serologically detectable specific and cross-reactive antigens on the membrane of a polyoma virus-induced murine tumor

With the aid of an assay measuring complement-dependent cytotoxocity mediated by syngeneic antibodies, we performed a serological analysis of surface antigens of a polyoma-virus-induced murine tumor (SEYF-a). In vivo propagated SEYF-a ascites tumor cells expressed a specific membrane antigen in addition to various other cross-reacting antigens. Among these we could identify at least four separate specificities. Two of these were present on MuLV-induced lymphoma cells, the first on Moloney-virus-induced YAC cells and the second on Gross-virus-induced GHA cells. The third cross-reacting antigen was detected on EL-4 cells. At least one additional specificity was present on two methylcholantthrene-induced murine sarcomas. Normal syngeneic lymphoid cells were insensitive to cytotoxicity mediated by the anti-tumor antisera. Quantitative and perhaps also qualitative differences between that antigenic expression of in vivo propagated on cultured SEYF-a cells were indicated. These studies show that hyperimmune sera produced in syngeneic mice against transplanted tumors may contain a considerable number of antibody specificities, only some of which are specific for the tumor. Furthermore, the results also suggest that polyoma-virus-induced tumors may possess individually distinct antigenic specificities, over and above the known cross-reacting TSTA or TSSA type antigen.