In vitro detection of cell-mediated immunity to individual tumor-specific antigens of chemically induced BALB/c fibrosarcomas.

In this study we have analyzed the in vitro cell-mediated cytotoxicity of immune peritoneal exudate cells (PEC), elicited in syngeneic mice against the MCA-induced, TSTA-bearing BALB/c fibrosarcoma CA-2, GI-17 and C-3. The 4 h 51Cr-release assay showed the immune PEC effectors to be specifically cytotoxic to fibrosarcoma used for the immunization, but not to other syngeneic MCA-induced tumors or normal fibroblasts. Cold target inhibition experiments on CA-2 cells confirmed the specificity of the reaction. When PEC, lymph-node and spleen cells from BALB/c anti-CA-2 mice were compared for anti-tumor activity, only PEC were found to kill tumor cells significantly. PEC effectors did not have a significant level of NK or NC activities since they were unable to destroy YAC-1 or WEHI-164 tumor cells. PEC anti-CA-2 were analyzed for the expression of T-cell markers by anti-Thy 1.2, anti-Ly 1.2 and Ly 2.2 monoclonal antibodies. Anti-tumor specific effector cells were identified as mature T cells since they were not adherent to plastic and showed Thy 1.2+, Ly 1.2- and Ly 2.2+ phenotypes. In addition, anti-H-2Kd but not anti-H-2Dd alloantiserum added to target cells, blocked CA-2 tumor lysis, thus supporting the conclusion that the T-cell response against TSTA is H-2 restricted.