FIG. 4.

Foxp3 binds the IL2, IFNγ, and TNFα promoters in virus-specific CD8⁺ T cells. CD8⁺ T cells from FIV- cats were cocultured with autologous CD4⁺CD25⁺ Treg cells (left column). Virus-specific CD8⁺ T cells from FIV⁺ cats 8 weeks (center column) and 6 months (right column) were either untreated (white bars, CFSE^low) or cocultured with autologous CD4⁺CD25⁺ Treg cells (CFSEl^ow+Treg). After 24 h, Foxp3 ChIP followed by quantitative polymerase chain reaction for IL2, IFNγ, and TNFα promoters were performed. Results show increased Foxp3 binding to the IL2, IFNγ, and TNFα promoters and (A–C) after coculture with autologous T reg cells at both 8 weeks and 6 months postinfection for FIV⁺ cats (n = 5–7 cats). FIV negative cats exhibited almost no Foxp3 binding to the various promoters following autologous Treg cell coculture. Bars represent the mean + SEM. Data were analyzed using an unpaired t-test with significance set at p < .05, asterisks. ChIP, chromatin immunoprecipitation.