Interferons Affect Oxygen Metabolism in Human Neutrophil Granulocytes

Abstract

Human polymorphonuclear neutrophil granulocytes (PMN) were incubated with recombinant interferons (IFNs) and tested for O₂ consumption, hydrogen peroxide formation, and chemiluminescence. N-formyl-methionyl-leucyl-phenylalanine (f-MLP, a bacterial peptide analogue) and phorbol myristate acetate (PMA, a protein kinase C activator) were used as PMN stimuli. An increase in O₂ consumption after f-MLP-stimulation was seen when PMN had been incubated 2-4 h with either 1000 IU/ml IFN-α or 100 IU/ml IFN-γ, Dut this increase in O₂ consumption was not observed with 1000 IU/ml IFN-β. Likewise, 100 U/ml IFN-γ enhanced f-MLP stimulated chemiluminescence, whereas IFN-α or IFN-β (1000 U/ml) had no detectable effects. None of the interferons affected baseline or PMA-stimulated O₂ consumption and chemiluminescence, nor did they influence the H₂O₂-dependent oxidation of intracellular dichlorofluorescin (DCFH) (baseline, f-MLP-stimulated or PMA-stimulated). Our data indicate that some—but not all — aspects of oxygen metabolism in PMN can be affected by IFN, and that there are differences between various subtypes of IFNs regarding their neutrophil priming potential.