Regulation of murine dendritic cell functions in vitro by taurine chloramine, a major product of the neutrophil myeloperoxidase-halide system

Taurine chloramine (TauCl) is a major chloramine generated in activated neu trophils as a result of the reaction of highly toxic hypochlorous acid and taurine, the most abundant free amino acid in cytosol. In this study we hav e tested the influence of TauCl on the properties of murine dendritic cells (DC), the major cell population involved in the initiation of an adaptive immune response against pathogenic organisms. N418(+), MHC II+, B7-2(+) den dritic cells, generated from the mouse bone marrow cells cultured in the pr esence of granulocyte-macrophage colony-stimulating factor, were stimulated by interferon-gamma and lipopolysaccharide to produce nitric oxide, reacti ve oxygen species, interleukin-6 (IL-6), tumour necrosis factor-alpha, and IL-12, in the presence of different doses of TauCl. TauCl differently inhib ited the generation of these inflammatory mediators in a dose-dependent man ner. Furthermore, TauCl selectively modulated the ability of DC to induce t he release IL-2 and IL-10 from T cells. These results suggest that neutroph il-derived mediators, such as TauCl, at a site of inflammation, may affect the functions of sentinel DC and macrophages, and play a role in maintainin g the balance between the inflammatory response and the induction of an ant igen-specific immune response.