Modulating DNA methylation in activated CD8+ T cells inhibits regulatory T cell-induced binding of Foxp3 to the CD8+ T Cell IL-2 promoter.

We have previously demonstrated that CD4(+)CD25(+) regulatory T cells (Tregs) activated during the course of feline immunodeficiency virus (FIV) infection suppress CD8(+) CTL function in a TGF-β-dependent fashion, inhibiting IFN-γ and IL-2 production and inducing G1 cell-cycle arrest. In this article, we describe the molecular events occurring at the IL-2 promoter leading to suppression of IL-2 production. These experiments demonstrate that Foxp3 induced by lentivirus-activated Tregs in the CD8(+) target cells binds to the IL-2 promoter, actively repressing IL-2 transcription.