Immunologic responses to a murine mammary adenocarcinoma: in vitro production of specific killer cells is dependent on active T lymphocytes.

The mode of production of specifically armed monocytic killer cells was investigated with the T1699 mammary adenocarcinoma in syngeneic DBA/2 mice. After overnight in vitro incubation of cells from the spleen but not from the lymph nodes, blood, or from the peritoneal cavity produced specific killer cells. The activation of spleen cells was inhibited by pretreatment with anti-theta serum and C; however, already activated specific killer cells were not sensitive to the same treatment. Removal of phagocytic cells did not significantly affect the cytotoxicity of the splenic killer cells whereas removal of rayon-wool adherent cells greatly reduced both the total cytotoxicity, and to a lesser extent, the cytotoxicity indices. Overnight co-cultivation of normal peritoneal-exudate cells with the lymph node cells from tumor-bearers, although neither class of cells alone was cytotoxic to T1699 cells in vitro, produced specific monocytic killer cells, through steps dependent on active T lymphocyte function. Culture spupernatants of tumor-bearer's spleen cells also contained factor(s) which induced cytotoxicity mediated by normal peritoneal-exudate cells against T1699 cells in vitro; and the production of the factor(s) was also inhibited by pretreatment of the spleen cells with anti-theta serum but not by anti-mouse IgG or anti-mouse whole gamma-globulins serum and C.