The effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the interaction between the fungus Torulopsis glabrata and human neutrophils was examined. Pre-incubation of neutrophils with GM-CSF increased the neutrophil fungal killing. The cytokine also increased the oxygen-dependent respiratory burst in response to opsonized fungi, measured by the lucigenin-dependent chemiluminescence assay and superoxide release. Under the same conditions the cytokine augmented release of constituents from both specific and azurophilic granules. Besides these priming effects, GM-CSF was a weak stimulus of the neutrophil respiratory burst and degranulation. The priming and stimulatory effects of GM-CSF were observed at 10-1000 U/ml with an optimal concentration of 100 U/ml.
