Preincubation of Candida albicans strains with amphotericin B reduces tumor necrosis factor alpha and interleukin-6 release by human monocytes

Abstract

The release of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) by human monocytes stimulated with whole heat-killed Candida albicans CA3 (a clinical isolate) and CA2 (a germ tube-negative mutant) either treated or not treated with amphotericin B was investigated. The optimal release of the cytokines was observed at 24 h of incubation of the yeasts with the monocytes for both TNF-alpha and IL-6. The levels ranged from 10,500 to 19,000 U/ml for TNF-alpha and from 350 to 460 pg/ml for IL-6. Germ tube-negative mutant CA2 induced the release of TNF-alpha at levels significantly (P < 0.05) lower than those induced by clinical isolate CA3, while no major differences were observed between the two strains with regard to their capacity to induce the release of IL-6. In all instances, preincubation of the yeasts with a sublethal concentration of amphotericin significantly reduced cytokine production. These results suggest that drug-induced alterations of fungal outer structures may affect the interactions between the yeasts and the monocytes, resulting in a reduced level of secretion of cytokines.