Novel aspect of amphotericin B action: accumulation in human monocytes potentiates killing of phagocytosed Candida albicans.

The influence of low doses of amphotericin B on the capacity of human monocytes to kill Candida albicans was investigated. Killing rates were quantified by a novel flow cytometric assay and were found to be 37% +/- 3% (standard error of the mean) after 3 h. Preincubation of monocytes for 6 to 20 h with low concentrations of amphotericin B (0.2 microgram/ml) resulted in a markedly augmented fungicidal capacity. Enhancement of killing was 80% +/- 11% (standard error of the mean) over that by the controls. This effect did not appear to be due to amphotericin B-dependent monocyte activation; the respiratory burst and expression of human leukocyte antigen-DR were unaltered, and no stimulation of…