Deficiency of FoxO3a in mice leads to spontaneous, autoreactive helper T cell activation and Th1 and Th2 cytokine production (Peng, 2008), which is required for controlling bacterial growth and clearance following Salmonella infection (Chappell et al., 2009; Talbot et al., 2009). Here, FOXO3 is linked to Salmonella Infections.