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 phe nylarsine oxide) and of an inhibitor of tyrosine kinase (genistein) on O-2(.-) production in mouse peritoneal macrophages wits examined. Van adate and phenylarsine oxide produced a dose-dependent inhibition of p horbol myristate acetate (PMA)-induced O-2(.-) production, whereas gen istein potentiated O-2(.-) production triggered by phorbol ester. Vana date had no effect on the respiratory burst in human neutrophils chall enged with fMLP, in agreement with previously published data on human intact neutrophils. It did not alter reduced nicotinamide adenine dinu cleotide phosphate (NADPH)-oxidase activity in membrane preparations o f mouse peritoneal macrophages. These data suggest that the phosphoryl ation of protein(s) in tyrosine residues blocked the PMA-dependent res piratory burst in mouse macrophages.