Requirements for T cells in alloantigen-induced generation of non-T cell-mediated cytotoxicity against syngeneic mouse sarcoma cells.

Abstract

In vitro stimulation of BALB/c spleen cells with allogeneic normal cells results in the generation of effector cells cytotoxic for syngeneic SV40 virus-induced MKSA fibrosarcoma cells. The conclusion that natural killer (NK) cells are activated that lyse the syngeneic tumor cells derives from findings that 1) treatment of the allostimulated BALB/c effector cells with anti-theta serum and complement does not ablate cytotoxicity against syngeneic MKSA tumor cells and 2) allostimulation of congenitally athymic (nu/nu) BALB/c mice results in significant cytotoxicity against MKSA tumor cells but not against allogeneic target cells. The requirement for the presence of theta-positive cells in alloantigen-induced activation of NK cells cytotoxic for syngeneic tumors was studied. Spleen cells from conventional BALB/c mice are cytotoxic for syngeneic MKSA tumor cells after stimulation with anti-theta serum-treated allogeneic cells or with allogeneic nude cells. In contrast, stimulation of BALB/c nude spleen cells with anti-theta serum-treated allogeneic cells or allogeneic nude cells fails to give rise to anti-tumor effector cells. Thus, theta-positive cells (presumably T cells) are required for alloantigen induced non-T cell-mediated lysis of syngeneic tumors.