Effect of intracerebral administration of Corynebacterium parvum on the growth of brain tumors in mice.

The effect of intracerebral administration of Corynebacterium parvum (C. parvum) on the growth of syngeneic brain tumors in C57BL/6 mice and the mechanism of its action were investigated. Mice were inoculated with 10(4) malignant glioma cells intracerebrally, and treated with various doses of C parvum on day 6 after tumor inoculation. The growth of tumors was significantly inhibited in proportion ot the dose of C. parvum. The cytotoxic activity of effector cells was enhanced when C. parvum was administered at the site of tumor inoculation. Significant cytotoxic activity was observed in the adherent cell fraction of brain mononuclear cells, while less cytotoxic activity was observed in the nonadherent cell fraction. These results indicate that activated intracranial macrophages may participate in the tumoricidal effect of intracerebral C. parvum administration.