Studies on the mechanism of lymphocyte-mediated cytolysis. VI. A reappraisal of the requirement for protein synthesis during T cell-mediated lysis.

The role of protein synthesis in the mechanism of T cell-mediated cytolysis has been re-investigated. Cytolytically active (C57BL/L anti-DBA/2) spleen cells treated with pactamycin (10-7 M to 10-6 M) exhibited suppressed protein synthesis (100 +/- 5%), but unimpeded lytic activity. Drug-treated effector cells, incubated for prolonged (up to 24 hr) periods of time in the presence and absence of antigen, showed no siginificant diminution of lytic activity although the incorporation of 3H-leucine into protein was totally ablated. Studies with emetine, another irreversible inhibitor of protein synthesis, gave identical results. These findings are difficult to reconcile with the hypothesis that effector T cells lysis via a soluble protein mediator.