Recombinant Interferon-γ Preserves Human Granulocyte Bactericidal and Chemoluminescence Activities

The effects of recombinant human interferon (IFN)-γ on functions of human granulocytes (PMNL) were investigated. Incubation with IFN-γ for up to 24 h enhanced the chemoluminescent (CL) response of polymorphonuclear leukocytes (PMNL) to Staphylococcus aureus, FMLP, opsonized zymosan, and PMA in a dose-dependent fashion for concentrations of 1-1000 units/mL. Short exposures to tumor necrosis factor (TNF)-α also enhanced the CL responses of PMNL, but the effects IFN-γ and TNFα together, at the concentrations used, were less than additive. Incubation of PMNL for 8 h with IFN-γ preserved their bactericidal capabilities relative to control PMNL incubated for the same length of time without IFN-γ. Preservation of neutrophil function may be a subtle but important role for IFN-γ.