Systemic adoptive transfer of immunity to 13762A rat mammary adenocarcinoma.

Rats cured of metastatic 13762A rat mammary adenocarcinoma by Corynebacterium parvum immunotherapy possess strong tumor-specific rejection immunity. Systemic adoptive transfer of lymphoreticular cells from cured rat donors conferred protective immunity on naive recipients. Fewer oil-induced peritoneal exudate cells than lymph node cells were required to transfer tumor rejection immunity. The adoptive immunity was specific since it strongly inhibited 13762A tumor growth but did not inhibit the growth of the antigenically unrelated R3230AC rat mammary tumor. Rats sensitized to the bacterial immune stimulant used to effect cure were unsuitable donors of PEC capable of transferring tumor rejection immunity. Macrophages or bone marrow-derived lymphocytes from immune donors did not transfer immunity. Treatment of peritoneal exudate with a xenogeneic antiserum specific for rat thymus-derived lymphocytes significantly reduced the efficiency of transfer. We conclude that thymus-derived lymphocytes from rats cured of 13762A tumor were required for the adoptive transfer of tumor-specific rejection immunity.