Antigens shared by rat schwannomas, neuroblastomas, and a testicular interstitial cell carcinoma.

Antigenic specificities and cross-reactivities of rat tumor cells were explored with rabbit antisera raised against a biochemically differentiated ethylnitrosourea-induced rat schwannoma cell clone, SCHW-RN-2. The hyperimmune anti-SCHW-RN-2 antisera were used to analyze the antigens of viable monolayers of rat cell cultures by an indirect sequential adsorption radioimmunoassay. Exhaustive mul tiple preabsorptions of the antisera with chicken embryo fibroblasts left antibodies reactive with 14 rat tumor cell cultures whether they were of nervous system (3 schwannomas, 2 neuroblastomas, and 2 astrocytomas) or non-nerv ous system (3 sarcomas and 4 carcinomas) origin. Syngeneic fibrosarcoma absorption completely removed activity against 6 of the non-nervous system tumors and the 2 astrocytomas, but left antibodies reactive with the 3 schwannomas, the 2 neuroblastomas, and an interstitial cell testicular tumor (CA-R2C). Reciprocal absorptions demon strated antibodies specific for 2 of the schwannomas but nonreactive with the third schwannoma, the neuroblas toma, or the interstitial cell testicular tumor. Absorption with either of the 2 positive schwannoma lines removed antibody reactivity for all 14 tumor cell lines. Thus, the rabbit anti-SCHW-RN-2 antisera detected 3 classes of anti gens: one shared by all 14 tumor cell lines, one limited to CA-R2C and tumor cells of neural crest origin, and a third limited to SCHW-RN-2 and one of the other two schwanno mas.