Antigen-specific cytotoxic T cell and antigen-specific proliferating T cell clones can be induced to cytolytic activity by monoclonal antibodies against T3.

T3 is a human differentiation antigen expressed exclusively on mature T cells. In this study it is shown that anti-T3 monoclonal antibodies, in addition to their capacity to induce T cells to proliferate, are able to induce antigen-specific cytotoxic T lymphocyte clones to mediate antigen nonspecific cytotoxic activity. It is furthermore shown that anti-T3 reagents are able to trigger lytic activity in T cell clones characterized as noncytotoxic antigen-specific proliferating T cells. The data presented indicate that perturbation of T3 can trigger the lytic machinery in cytolytic as well as noncytolytic T cell clones.