Effect of interferon-α on production of reactive oxygen species by human neutrophils

In order to examine that the effects of interferon alpha (IFN-α) on the production of reactive oxygen species from human neutrophils, we investigated in vitro effects of IFN-α on neutrophil chemiluminescence responses. Human neutrophils were incubated with 0-1 × 10⁵ IU/mL IFN-α for 10-60 min just before stimulation with opsonized zymosan and phorbol 12-myristate 13-acetate. Luminol-dependent (LmCL) and lucigenin-dependent (LgCL) chemiluminescence responses were measured using a Lumi Box H-1000. The LmCL response was inhibited by pre-incubation with high concentrations of IFN-α (more than 1 × 10⁴ IU/mL). In contrast, LgCL response was increased when neutrophils were pre-incubated with high concentration of IFN-α. Effects of preincubation of IFN-α were similar between CL responses stimulated with OZ and PMA. The increase of LgCL might be due to the inhibitory effect of IFN-α on myeloperoxidase degranulation, in view of the decreased LmCL responses.