Recombinant human granulocyte colony-stimulating factor enhances superoxide release in human granulocytes stimulated by the chemotactic peptide.

Recombinant human granulocyte colony-stimulating factor (G-CSF) by itself was not an effective stimulus for inducing the release of superoxide (O-2) in human granulocytes. However, G-CSF was able to prime human granulocytes, and enhanced O-2 release stimulated by the chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (FMLP). The preincubation with G-CSF for 5-10 min at 37 degrees C was sufficient for priming the cells. The optimal enhancing effect was obtained at 25 ng/ml of G-CSF. The enhancement of O-2 release by G-CSF was observed over the complete range of effective concentrations of FMLP (10(-8)-10(-6) M). These findings indicate that G-CSF is a potent activator of mature granulocyte functions.