Modulation of neutrophil functions by a beta-interferon of human origin

The effects of a β interferon (β-IFN) of human origin on different parameters of human neutrophil functioning were evaluated in vitro. In the concentration range 10²-10⁴ IU/ml β-IFN enhanced superoxide anion production evoked by the peptide N-formylmethionyl-leucylphenylalanine (FMLP), 10^-7 M, when superoxide anion production elicited by FMLP in the absence of β-IFN treatment was 2.43 ± 0.32 nmol cytochrome C reduced/10⁶ cells/min. The enhancement afforded by 10³ and 10⁴ IU/ml β-IFN was statistically significant. When FMLP-induced superoxide anion generation was 4.55 ± 0.3 nmol cytochrome C reduced/10⁶ cells/min, no increase was detected after β-IFN treatment. Phagocytosis was enhanced by β-IFN in one case, with no effect in four others. Chemotaxis was not affected by exposure to β-IFN. These results indicated that β-IFN could exert modulating effects on some neutrophil functions that varied according to the extent of cell response to the stimuli.