Suppressive effects of interleukin-10 on human mononuclear phagocyte function against Candida albicans and Staphylococcus aureus

The effects of interleukin (IL)-10, a potent antiinflammatory cytokine, on human monocyte functions against two medically important pathogens, Candida albicans and Staphylococcus aureus, were studied. Incubation with 20-100 n g/mL IL-10 for 2-3 days decreased the fungicidal activity of monocytes agai nst serum-opsonized C. albicans blastoconidia (P less than or equal to.04), reduced their capacity to damage unopsonized hyphae (P less than or equal to.006), and suppressed superoxide anion production in response to phorbol myristate acetate (P=.019) and N-FMLP (P=.04) but not to serum-opsonized bl astoconidia. Paradoxically, IL-IO enhanced phagocytic activity of monocytes against serum-opsonized blastoconidia (P<.01). In addition, IL-10-treated monocytes demonstrated decreased bactericidal activity (P=.046) but no chan ge in bacterial phagocytosis. These findings demonstrate an overall suppres sive role of IL-10 on human monocyte function against C. albicans and S. au reus and may have important implications in the use of this cytokine.