Granulocyte-macrophage colony-stimulating factor (GM-CSF) primes the respiratory burst and stimulates protein biosynthesis in human neutrophils.

Pre-treatment of human neutrophils with rGM-CSF resulted in a 3-fold increase in the rate of fMet-Leu-Phe stimulated reactive oxidant generation, as assessed by luminol- and lucigenin-chemiluminescence and O2- secretion. When blood-stream neutrophils were incubated in RPMI 1640 medium supplemented with [35S]methionine, both fMet-Leu-Phe (0.1 microM) and gamma-interferon (100 U/ml) stimulated a 3-4-fold increased incorporation of label into TCA-precipitable material. Similarly, rGM-CSF (50 U/ml) also stimulated protein biosynthesis in bloodstream neutrophils, and newly labelled polypeptides were separated by two-dimensional polyacrylamide gel electrophoresis. Two classes of polypeptides were visualised on these gels: the relative rate of labelling of one class changed very little upon rGM-CSF treatment whereas the relative rate of labelling of a second group increased 3-12-fold.