6. Taurine, taurine derivatives and the immune system

Taurine, a non-protein sulfur amino acid, is the most abundant free amino-acid in the body and plays an important role in several essential biological processes such as bile acid conjugation, maintenance of calcium homeostasis, osmoregulation, and membrane stabilization [1,2,3]. Taurine reaches particularly high concentrations in tissues with high oxidative activity and in tissues exposed to elevated levels of oxidants (retina, kidney, heart, immune inflammatory cells) [4,5]. It suggests that cytoprotective properties of taurine, demonstrated in various in vitro and in vivo studies, attribute primarily to its antioxidant activity and are not tissue specific [6, 7]. At a site of inflammation, taurine is known to react and detoxify hypochlorous acid (HOCl) generated by neutrophil myeloperoxidase–halide system. This reaction results in formation of less toxic taurine chloramine (TauCl) [8,9]. TauCl, as well as taurine bromamine (TauBr), the product of taurine reaction with hypobromous acid (HOBr), exerts anti-inflammatory, anti-oxidant, proapoptotic, and antibacterial properties [10,11,12,13]. This review summarizes