Spontaneous clones of cytotoxic T cells in culture. III. Discriminatory lysis of pairs of syngeneic blast induced by different mitogens.

When normal spleen cells are cultured for 4 days in polyacrylamide vessels, individual clones of cytotoxic lymphocytes (CL) can be detected. The specificity of these 'spontaneous' CL was investigated by assaying the cytotoxic acitivity of cells from individual clones against pairs of different target. Target cells used were syngeneic blast cells induced by dextran sulfate, lipopolysaccharide (LPS), concanavalin A (ConA) and phytohemagglutin (PHA). It was found that LPS blasts were lysed by a separate set of CL clones from those which lysed PHA blasts of the same H-2 haplotype, and the clones of CL which lysed PHA blasts were a subset of all the clones which lysed ConA blasts. When individual clones of spontaneous CL were assayed against LPS and DS blasts, there were clones which lysed both types of blasts as well as clones which were specific for either LPS or DS blasts. These results have been interpreted as demonstrating that spontaneous CL can recognize and kill subsets of cells which are stimulated by different mitogens.