Effects of Corynebacterium parvum on tumour metastases in mice.

Abstract

AbstractThe effects of Corynebacterium parvum on the Lewis lung tumour and its metastases have been studied. Intravenous but not intraperitoneal or subcutaneous C. parvum reduced the growth of the primary tumour. Both intravenous and intraperitoneal C. parvum significantly reduced pulmonary metastases. When combined with excision of the primary tumour, C. parvum given not more than 2 days before excision caused only slight reduction of metastases, but when given intravenously or intraperitoneally 3–4 days before excision, metastases were significantly reduced and some mice were cured of tumour. Subcutaneous C. parvum had no effects on metastases.Non-specific operation (amputation) increased tumour metastases, but C. parvum counteracted this.Metastases were significantly increased by the administration of silica and cortisone acetate but were unaffected by trypan blue. The antimetastatic action of C. parvum was not significantly altered by these treatments. Thymectomy and irradiation did not affect tumour metastases or the antimetastatic action of C. parvum, whereas antilymphocyte serum depressed metastasis and abrogated the protective effects of C. parvum.It appears that the inhibitory effects of C. parvum on tumour metastases are mediated through macrophages in concert with a subpopulation of T2 lymphocytes.