SUPPRESSION OF INTRACELLULAR HYDROGEN-PEROXIDE GENERATION AND CATALASE LEVELS IN CD8(-LYMPHOCYTES FROM HIV+ INDIVIDUALS() T)

CD8(+) T-lymphocytes from HIV+ individuals contain short telomeres, a sign of cell senescence. To rest our hypothesis that the cell type is functionally defective in the biochemical indices related to cell prol iferation, we investigated the profiles of intracellularly generated H 2O2 levels with or without PMA as well as immunoreactive catalase leve ls using flow cytometric method. We observed that, in HIV+ but not in HIV- individuals, the constitutively generated H2O2 level was signific antly lower in CD8(+) T-cells compared with CD4(+) T-cells. Importantl y, activated effector CD8(+)CD28(-) cells showed remarkably low H2O2 l evels compared with CD8(+)CD28(+) cells, and the latter in HIV+ indivi duals also showed low levels. A similar defect of CD8(+) cells of HIV individuals was also seen with H2O2 levels stimulated with PMA in the presence of a catalase inhibitor. Furthermore, the immunoreactive cat alase content was lower in CD8(+) cells compared with CD4(+) cells onl y in HIV+ individuals. These results suggest that CD8(+) T-lymphocytes are functionally defective with the constitutively generated and PMA- elicited levels of H2O2 and the corresponding scavenger. Diminished im munocompetence of HIV+ individuals may be caused, in part, by the func tional defect of CD8(+) T-cells. (C) 1998 Elsevier Science Inc.