MODULATION OF ANTIGEN-SPECIFIC T-CELL ACTIVATION IN-VITRO BY TAURINE CHLORAMINE

Taurine chloramine (TauCl) is produced during inflammation by reaction of hypochlorous acid (HOCl) with taurine, the most abundant free amin o acid in neutrophils. We previously reported that TauCl inhibits the generation of macrophage inflammatory mediators such as nitric oxide, prostaglandin E-2 (PGE(2)), tumour necrosis factor-alpha (TNF-alpha) a nd interleukin-6 (IL-6). In this study, the activity of TauCl in modul ating T-cell activation was investigated. Treatment of T cells with Ta uCl (0.1-0.3 mM), prior to activation, was found to inhibit interleuki n-2 (IL-2) release in response to both mitogen and antigen stimulation . Similarly, pretreatment of A-20 antigen presenting cells (APCs), at low cell numbers, was found to inhibit their ability to process and pr esent ovalbumin (OVA) to a specific T-cell hybridoma. In contrast, pre treatment of higher numbers of A-20 cells with TauCl in the presence o f OVA enhanced subsequent presentation of OVA. Finally, OVA modified w ith TauCl was processed and presented more efficiently than native OVA . Thus. TauCl is able to modulate induction of a specific adaptive imm une response at several independent points of the overall antigen-pres enting pathway.