Cell mediated immunity in mice immunized with modified syngeneic gross lymphoma antigen

Many investigators have shown lymphocyte mediated cytotoxicity to be important in tumor immunity. With our system, the direct cytotoxicity assay with ⁵¹Cr did not show activity of spleen cells. The adherent peritoneal exudate cell (pec) did have a direct inhibitory effect which seemed to be augmented by both lymphocytes and a serum factor. This augmentation factor may have been the specific arming factor (SMAF) reported by Alexander or an immunoglobulin. The presence of antibodies to the tumor antigen suggests that humoral immunity is somehow involved.