TAURINE CHLORAMINE DOWN-REGULATES THE GENERATION OF MURINE NEUTROPHILINFLAMMATORY MEDIATORS

We previously reported that taurine chloramine (TauCl), a product of a ctivated neutrophils, inhibits the generation of macrophage inflammato ry mediators such as nitric oxide (NO), TNF-alpha, and PGE(2). Taurine , the most abundant free amino acid in the cytosol of neutrophils, is chlorinated to form TauCl by the halide-dependent myeloperoxidase (MPO ) system. Under physiological conditions, TauCl reduces HOCl toxicity. In this study, we investigated the influence of TauCl on generation o f oxygen free radicals, cytokines and eicosanoids by activated murine peritoneal neutrophils. We found that TauCl, but not taurine alone, in hibited the production of NO, prostaglandin E-2, interleukin-6 and tum or necrosis factor-alpha, in a dose-dependent manner. In contrast, the products of the respiratory burst, as measured by luminol-dependent c hemiluminescence (LCL), were reduced by both taurine and TauCl. Howeve r, taurine affected LCL at higher concentrations and to a lesser exten t than TauCl. The results of these studies suggest that TauCl decrease s production of tissue-damaging inflammatory mediators and may regulat e the balance between protective, microbicidal and toxic effect of neu trophils. (C) 1998 Elsevier Science B.V. All rights reserved.