HIV antigens can induce TGF-β1-producing immunoregulatory CD8+ T cells

HIV-infected individuals may progressively lose both HIV-specific and unrelated CTL responses despite the high number of circulating CD8(+) T cells. In this study, we report that similar to25% of HIV+ donors produced TGF-beta(1) in response to stimulation with HIV proteins or peptides. The production of TGF-beta(1) was sufficient to significantly reduce the IFN-gamma response of CD8+ cells to both HIV and vaccinia virus proteins. Ab to TGF-beta reversed the suppression. We found the source of the TGF-beta(1) to be predominantly CD8(+) cells. Different peptide pools stimulated TGF-beta(1) and IFN-gamma in the same individual. The TGF-beta(1) secreting cells have distinct peptide specificity from the IFN-gamma producing cells. This represents an important mechanism by which an HIV-specific response can nonspecifically suppress both HIV-specific and unrelated immune responses.