Abstract
Transforming growth factor-β (TGF-β) is a multifunctional cytokine secreted by many mononuclear cells in peripheral blood (PBMC) and has diverse effects on cellular and humoral immunity. Increased TGF-β mRNA expression has been reported in PBMC of HIV-infected patients, but the mechanism by which HIV induces TGF-β secretion is unknown. In this study, we observed that HIV gp160 could induce significant TGF-β secretion and TGF-β mRNA expression in PBMC from HIV-seronegative healthy donors. The cellular source of TGF-β was attributed to non-T cells, presumably monocytes. Specificity of secreted TGF-β was confirmed by the addition of anti-TGF-β mAb which abrogated the proliferative response of CCL-64 cells by gp160-treated culture supernatants. Soluble CD4 blocked the gp160-induced TGF-β production, suggesting that CD4–gp160 interaction is required to induce TGF-β production. Our results suggest that HIV-1 gp160 may contribute to the immune defects in HIV infection by inducing TGF-β secretion.
