THE EFFECT OF GM-CSF AND G-CSF ON HUMAN NEUTROPHIL FUNCTION

A direct comparison of GM-CSF and G-CSF in a panel of in vitro neutrop hil-function assays was performed to investigate any differences in ac tivity profiles. In our modified chemotactic assay, GM-CSF rapidly inc reased the migratory capacity of polymorphonuclear cells (PMNs) to mov e toward fMLP and LTB(4). In contrast, G-CSF only stimulated PMN migra tion towards fMLP. GM-CSF, but not G-CSF, increased PMN cytotoxic kill ing of C. albicans blastospores. The expression of PMN surface antigen s associated with Fc- and complement-mediated cell-binding (Fc gamma R 1, CR-1 and CR-3), and adhesion signalling (ICAM-1), was increased aft er the exposure of GM-CSF, but not to G-CSF. In contrast these CSFs de monstrated relative equipotency in their ability to induce PMN anti-ba cterial phagocytosis, and to restore the Staphylococcus aureus killing capacity of dexamethasone-suppressed neutrophils. The phagocytic acti vity of PMNs for opsonized yeast, as well as hexose-monophosphate shun t activity, was equivalent following GM-CSF or G-CSF treatment. We dis cuss the significance of the difference in activity profiles in this a rticle.)