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Roos A, Claessen N, Schilder-Tol EJ, Chand MA, Weening JJ, Aten J: Thiol levels in CD134-defined subsets of rat T lymphocytes: possible implications for HgCl2-induced immune dysregulation. Biochem Biophys Res Commun. 1997 Nov 17;240(2):452-7.
CD134 (OX40), a member of the tumour necrosis factor receptor family, is expressed on activated T cells and mediates T and B cell costimulation. Its expression is increased after exposure to the thiol-binding compound HgCl2 in BN rats, but not in Lewis rats, in association with induction of a T cell-dependent systemic autoimmune syndrome only in BN rats. Intracellular thiols are involved in regulation of activation and death in T lymphocytes. Therefore, we examined intracellular thiol levels in CD134-defined T cell subsets from BN and Lewis rats. Levels of total thiols and glutathione (GSH) were significantly higher in CD134+CD4+ cells than in CD134+CD4+ cells in both strains. In Lewis rats, total thiol levels in CD4+CD134+ cells, but not in CD4+CD134+ cells, were higher than in BN rats. In contrast, BN rats showed higher GSH levels in CD4+CD134+ cells, but not in CD4+CD134+ cells. In vitro exposure to HgCl2 decreased intracellular thiol levels, predominantly in CD4+CD134+ cells. Furthermore, HgCl2-induced enrichment of CD134+ viable cells was inversely correlated to HgCl2-induced cell death. Strain-dependent differences in thiol levels in CD134-defined subsets of CD4+ lymphocytes and subset-specific modification of thiol levels may contribute to differential lymphocyte activation by oxidizing chemicals. |
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