Recognition of Rous sarcoma virus-induced tumor antigens by cytotoxic T lymphocytes (CTL): studies on specificity of killing by CTL employing H-2 congenic and recombinant mouse tumor cells.

The specificities of cytotoxic T lymphocytes (CTL) were studied for the analysis of CTL against tumor-specific cell surface antigen(s) (TSSA) of non-virus-producing tumor cells induced by the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) in B10 congenic and recombinant mice. Eight CTL clones were established from immune spleen cells of B10.A(5R) mice. These clones demonstrated six patterns of cytotoxic reactivity in vitro: Two clones showed H-2 restriction in tumor cell lysis. Two other clones had the capacity to lyse syngeneic, H-2K-compatible B10 and H-2-incompatible B10.A(4R) tumor cells, but not YAC-1 cells. One clone had cytotoxic activity against syngeneic, H-2D-compatible B10.D2 tumor cells and YAC-1 cells, but not against H-2-incompatible tumor cells. One clone had cytotoxic activity against syngeneic and YAC-1 tumor cells, but not against either H-2-compatible or H-2-incompatible tumor cells. One clone had lytic activity to syngeneic, H-2-compatible, H-2-incompatible, and YAC-1 tumor cells. Another clone killed H-2-incompatible B10.A(4R) tumor and YAC-1 cells, but not syngeneic or H-2-compatible tumor cells. All these clones strongly expressed surface Thy-1.2 antigens, whereas the expression of Lyt-1.2 and Lyt-2.2 antigens was different from clone to clone. These results demonstrate heterogeneity of both lytic specificity and phenotype of CTL against RSV-induced mouse tumor cells, suggesting the existence of multiple antigenic sites on the RSV TSSA recognized by CTL populations.