CD8A and infection: Pro-inflammatory cytokine released in the early phase of infection and sepsis by Th1 cells, CD8+ T cells and NK cells. Essential for T cell Th1 differentiation. Activates T cells and NK cells. Promotes phagocytosis, expression of MHC I and II, antigen presentation, pro-inflammatory cytokine secretion, production of IgG, oxidative, and nitrosative stress