Activation of bovine neutrophils by recombinant interferon-gamma

The effect of recombinant bovine interferon-gamma (r-IFN-gamma) on neutrophil functions was investigated and compared to the effects of an unpurified lymphokine preparation. Incubation of purified bovine neutrophils with r-IFN-gamma or antigen-induced lymphokine for 2.5 hr at 37 degrees C resulted in impairment of the ability of neutrophils to migrate under agarose, and an enhancement of their ability to mediate antibody-dependent and antibody-independent cell-mediated cytotoxicity against chicken erythrocytes. Neither the lymphokine preparation nor the r-IFN-gamma had any influence on Staphylococcus aureus ingestion, or iodination by neutrophils. The lymphokine preparation enhanced cytochrome c reduction by neutrophils and was weakly chemotactic, whereas the r-IFN-gamma had neither of these effects. Only 5 min of r-IFN-gamma preincubation with neutrophils were needed to trigger protein synthesis by the neutrophils resulting in inhibition of random migration. Therefore, recombinant interferon-gamma acts as a neutrophil migration inhibition factor and a neutrophil activation factor resulting in enhanced neutrophil-mediated antibody-dependent and -independent cell-mediated cytotoxicity. Many, but not all, of the in vitro effects of an unpurified lymphokine preparation on neutrophil function can be attributed to the interferon-gamma contained in the lymphokine.