Dissociated effect of amphotericin B and desoxycholate on phagocytosis of Escherichia coli by human polymorphonuclear neutrophils.

The influence of commercial amphotericin B-desoxycholate (Fungizone) and desoxycholate alone on phagocytosis of Escherichia coli by human polymorphonuclear neutrophils in vitro was studied. A dissociated effect of amphotericin B and desoxycholate was observed. Amphotericin B was shown to stimulate the ingestion of Escherichia coli through an effect on the bacteria as well as on the neutrophils. Desoxycholate inhibited phagocytosis through an effect on the neutrophils and also, at low concentrations (0.08 microgram/ml), through an effect on the bacteria. On the other hand, pretreatment of Escherichia coli with high concentrations (8.2 micrograms/ml) of desoxycholate rendered it more susceptible to phagocytosis. The elimination of bacterial breakdown products from the neutrophils after ingestion of Escherichia coli was also inhibited by desoxycholate and stimulated by amphotericin B. Most of these effects disappeared in the presence of 10% serum. An alteration of bacterial hydrophobicity could only partly explain the effect of amphotericin B.