Protection by corynebacterium granulosum against radiation-induced enhancement of artificial pulmonary metastases of a murine fibrosarcoma.

Abstract

Intraperitoneal treatment of C3Hf/Bu mice with killed Corynebacterium granulosum bacteria before intravenous inoculation of cells from a syngeneic fibrosarcoma greatly reduced the number of metastatic nodules in the lung. In contrast, the number of pulmonary metastases was significantly increased in mice previously given whole-body irradiation of 200–600 rads of γ-rays. Pretreatment of animals with C. granulosum before irradiation not only abolished this effect but also produced a response equal to that in mice treated with the immunostimulant alone. C. granulosum protected the mice against radiationinduced enhancement of pulmonary metastases if given within 2, but not at 4, weeks before irradiation. However, if mice were first irradiated and then, 1 or 2 days later, treated with C. granulosum, the radiation effect on the formation of pulmonary metastases was not influenced.