[Effects of astromicin on a host defence mechanism]

We investigated the effect of astromicin (ASTM) on a defence mechanism. The existence of ASTM (100 micrograms/ml) did not influence the ability of phagocytizing and killing by the mouse peritoneal exudated polymorphonuclear leukocyte (PMN). We observed no change of either phagocytizing and killing or phagocytizing ability of PMN by a pretreatment with ASTM (100 micrograms/ml). When the luminol-dependent chemiluminescence of PMN was examined, a slight decrease of relative light intensity in the presence of ASTM was observed at a concentration of 100 micrograms/ml or 50 micrograms/ml. There was, however, no change of relative light intensity in the presence of 20 micrograms/ml of ASTM. The chemotaxis of PMN was not influenced in the presence of even 100 micrograms/ml of ASTM. We also examined whether a combination effect existed between ASTM and either fresh human serum or fresh mouse serum in vitro. Considerable combination effects were observed against E. coli, P. aeruginosa, S. marcescens, K. pneumoniae and S. aureus. From these results, we concluded that ASTM did not exert a detrimental effect on examined functions of PMN which is important in the nonspecific host defence mechanism in the early phase of bacterial infections. We also concluded that ASTM, which had a synergic effect with a human serum factor, was a safe and effective chemotherapeutic agent.