HIV-1 tat induced apoptosis of T-cells is not mediated by TGF-beta

Recent reports have demonstrated that the HIV-1 transactivator protein, fat , induces apoptosis in T-lymphocyte cell lines, as well as in peripheral bl ood mononuclear cells, and stimulates a cascade of events resulting in up-r egulation of the potent immunosuppressive cytokine, transforming growth fac tor-beta (TGF-beta), In this study we evaluated the ability of TGF-beta to mediate tat induced apoptosis in T-lymphocyte cell lines. T-cells treated e xogenously with either TGF-beta 1 or a combination of tat and pan-specific TGF-beta neutralizing antibodies showed little change in the amount of apop tosis, When treated with pan-specific TGF-beta neutralizing antibodies, Jur kat cells that stably express tat protein (Jurkat-tat) showed only a modest decrease in apoptosis, while CEM-TART cells (CEM T-cells expressing both H IV-1 fat and rev) demonstrated little change in the amount of apoptosis. In conclusion, we have demonstrated that TGF-beta does not play a significant role in mediating fat induced T-cell apoptosis.