Cytocidal and cytostatic ability of Corynebacterium liquefaciens in mouse squamous cell carcinoma in vivo

The cytostatic and cytocidal action of Corynebacterium liquefaciens was studied in a mouse squamous cell carcinoma in vivo. Kinetic analysis of tumor cells 4 and 8 days after a single i.p. dose of 2.0 mg C. liquefaciens showed a marked prolongation of the mean cell generation time (TG). This prolongation affected most the G1 and, to a lesser extent, the S phases of the cell cycle. The tumor growth factor was decreased, and the mean value of the cell loss factor was increased. Assays to determine the number of tumor cells needed to produce the tumor in one-half of the transplant recipients showed that peritoneal exudate cells collected from mice given injections of C. liquefaciens exerted tumor cell killing that depended on the peritoneal exudate cell tumor:cell ratio. This cell killing was not found with peritoneal exudate cells from normal or proteose peptone-treated mice.