MODULATION OF PHORBOL ESTER-INDUCED RESPIRATORY BURST BY VANADATE, GENISTEIN, AND PHENYLARSINE OXIDE IN MOUSE MACROPHAGES

The effect of the inhibitors of tyrosine phosphatase (vanadate and phenylarsine oxide) and of an inhibitor of tyrosine kinase (genistein) on O-2(.-) production in mouse peritoneal macrophages wits examined. Vanadate and phenylarsine oxide produced a dose-dependent inhibition of phorbol myristate acetate (PMA)-induced O-2(.-) production, whereas genistein potentiated O-2(.-) production triggered by phorbol ester. Vanadate had no effect on the respiratory burst in human neutrophils challenged with fMLP, in agreement with previously published data on human intact neutrophils. It did not alter reduced nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activity in membrane preparations of mouse peritoneal macrophages. These data suggest that the phosphorylation of protein(s) in tyrosine residues blocked the PMA-dependent respiratory burst in mouse macrophages.