Tumor-associated Antigens of Chemically-induced Murine Tumors; the Emergence of MuLV and Fetal Antigens After Serial Passage in Culture

Using radioiodinated Staphylococcus aureus protein A [125I]SPA to measure syngeneic, allogeneic and heterogeneic IgG bound to murine tumor cells, we performed a serological analysis of surface antigens of 8 solid tumors and 2 leukemias of BALB/c mice (3 chemically-induced colon carcinomas, 3 chemically-induced sarcomas, 1 murine leukemia virus (MuLV) induced leukemia, 1 irradiation induced leukemia, 1 spontaneous melanoma and 1 spontaneous sarcoma). We were able to detect and distinguish between at least five separate antigenic specificities on these tumors. Unique tumor-associated antigens were found on 3 of the tumors, MuLV related antigens on 8 tumors, fetal antigens on 7 tumors and two distinct common antigens on 7 tumors (common antigen 1 (CA-1) on 5 tumors and common antigen 2 (CA-2) on 2 tumors). Neither of the common antigens was found to be sarcoma, carcinoma or tissue-tupe specific. A number of tumors which did not originally express either MuLV or fetal antigens in primary cultures expressed these antigens after several serial passages in vitro.