Enhancement of macrophage candidacidal activity by interferon-gamma.

In previous studies, we have reported that opsonized candida species are ingested by monocytes and monocyte-derived macrophages (MDM), but uptake of unopsonized candida is mediated only by MDM, primarily through the mannose receptor (MR). This study examines the effects of recombinant IFN-gamma on the uptake and killing of unopsonized C. albicans by MDM. We report here that MDM treated with IFN-gamma developed an increase in their capacity to ingest and kill unopsonized C. albicans and to release O2- upon stimulation with candida. Mannan (0.1 to 5 mg/ml) inhibited uptake of candida in a dose-dependent manner, but glucan (5 mg/ml) did not. These data suggest that mannose receptors may be involved in the increased phagocytosis and killing of unopsonized candida by human macrophages treated with IFN-gamma.