The effect of Corynebacterium parvum on T cell dependent tumor regression

Systemic administration of Corynebacterium parvum has been reported to depress a variety of T cell-mediated responses (3, 8, 14). We have examined its influence upon the development of T cell dependent antitumor immunity during growth of a syngeneic fibrosarcoma (FSA). T cell-mediated antitumor immunity was demonstrated in the spleens of Fsa bearing mice by the Winn assay. Its level was in general enhanced by C. parvum treatment. This was especially true around the time of C. parvum-induced tumor regression. However just before regression there was a consistent decrease in the level of splenic antitumor immunity in C. parvum treated mice again as measured by the Winn assay. This depression was not found when the cells were adoptively transferred to Fsa bearing recipients suggesting that the adoptive transfer assay and the Winn assay measure different functional attributes of the T cell populations.