Suppressive Effects of Interleukin‐10 on Human Mononuclear Phagocyte Function againstCandida albicansandStaphylococcus 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 ng/mL IL-10 for 2-3 days decreased the fungicidal activity of monocytes against serum-opsonized C. albicans blastoconidia (P</=.04), reduced their capacity to damage unopsonized hyphae (P</=.006), and suppressed superoxide anion production in response to phorbol myristate acetate (P=.019) and N-FMLP (P=.04) but not to serum-opsonized blastoconidia. Paradoxically, IL-10 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 change in bacterial phagocytosis. These findings demonstrate an overall suppressive role of IL-10 on human monocyte function against C. albicans and S. aureus and may have important implications in the use of this cytokine.