IFNG and infection: However, when we focused on specific cytokine promoters in PBMC-derived CD8+ T cells, cytokine-specific differences emerged where there was a significant decrease in promoter methylation for the IFNγ promoter, a trend towards decreasing methylation for the IL-2 promoter, but an increase in TNFα promoter methylation post SIV-infection compared to prior to infection (Figure 2).