The accumulated effects of repeated systemic or local injections of low doses of Corynebacterium parvum in mice.

The effects of 14 weekly injections, s.c. or i.v., of "human equivalent" doses (5.25 mg/sq m) of Corynebacterium parvum (CP) in mice have been compared. Both s.c. and i.v. CP caused significant splenomegaly and antibody to CP, but stimulation was considerably greater after i.v. CP. Delayed hypersensitivity levels to CP were similar after s.c. and i.v. injection. T-cell competence, as judged by phytohemagglutinin reactivity and delayed hypersensitivity to sheep cells, was unimpaired after s.c. CP and augmented by i.v. CP. Activated peritoneal macrophages capable of nonspecifically inhibiting tumor growth in vitro were detected only after i.v. CP, and in vivo resistance to tumor cell challenge was greater after CP administered i.v. than s.c.