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.