What is the role of T regulatory cells in HIV-1 infection?
HIV-1 infection leads to a massive depletion of CD4+ T lymphocytes. The actual mechanisms of CD4+ T cell depletion remain to be understood. CD4+CD25+ regulatory T cells (Tregs) suppress the activation and proliferation of effector lymphocytes. Dysregulation of these cells in the peripheral blood and lymphoid tissue has been reported in HIV-1 infection. To elucidate the role of Tregs in HIV-1-induced depletion of CD4+ T cells, we use a pigtailed macaque model of HIV-1 disease to determine the distribution of Tregs in a setting of acute infection, using Foxp3 as a marker for Tregs. Real-time PCR is used to quantitate FOXP3 copy number in SIV-infected and uninfected control macaques. In addition, in-vitro suppressor assays are used to determine if Treg function is present. We have found disturbances in the Treg subset in both SIV and HIV-1 infection and are focused on determining what effects the loss Treg-mediated suppression has on the pathogenesis of the disease.