Cell-Mediated Immunity in Host after Tumor Irradiation ¹

Abstract

The immunological activity of the host after tumor irradiation was investigated in in vivo and in vitro system. The spleen cells from tumor irradiated mice inhibited growth of tumor in mice which were inoculated tumor cells together with these spleen cells. These spleen cells also inhibited the colony formation, and tumor growth in in vitro system. The cytostatic activity of spleen cells against tumor cells was enhanced after local tumor irradiation. It was also shown that enhancement of specific anti-tumor cell-mediated immunity of spleen cells in host occurred 7 or more days following local irradiation to tumor and continued for several weeks.