Abstract
The cytotoxic activities of polymorphonuclear leukocytes (PMN) induced by intraperitoneal (i. p.) administration of OK-432 or Nocardia rubra cell wall skeleton (N-CWS) were examined by a 51Cr release assay. Male C3H/He mice, 8_??_10 weeks old, and syngeneic MM46 mammary adenocarcinoma cell line were used in this experiment. PMN accumulated in the peritoneal cavity 6 hrs after i. p. injection of 1 KE of OK-432 or 200μg of N-CWS showed no cytotoxicity. Very strong cytolysis, more than 80%, was obtained when PMN was cultured with N-CWS in the concentrations from 10μg/mll to 100μg/ml, while the addition of OK-432 in vitro did not enhance the cytotoxicity. This enhanced cytotoxicity by the addition of N-CWS was observed at effector: target ratios from 0.7 to 50. It is concluded that combined use of different kinds of biological response modifiers such as OK-432 and N-CWS enhances cytotoxicity of PMN.
