Suppression of cell-mediated immunity through immune spleen cells against Ehrlich ascites tumor.

The adoptive transfer of immunity to Ehrlich ascites tumor was accomplished during the first two weeks in a syngeneic murine system by the intraperitoneal administration of spleen cells obtained from mice which had been hyperimmunized through three subcutaneous inoculations with the tumor. The resistance induced in this system was noted duing first two weeks after tumor challenge, and thereafter there was an increased tendency for the tumor to become enhanced. Serum from mice which had previously contacted with Ehrlich ascites tumor showed enhancing effect on the subcutaneous growth of the tumor to a certain degree. Anti-tumor effect of spleen cells from various donors was examined by a simple method involving intraperitoneal injection of tumor cells and spleen cells which had been mixed and incubated for a short period of time. The results seem to indicate that suppression of tumor growth was induced by cell-mediated immunity through injected immune spleen cells, and that enhancement of tumor growth depended basically upon the ability of humoral antibodies which apparently had been produced through transferred spleen cells to suppress the development of cell-mediated immune response.