CD4 and infection: While this would argue against a neuroprotective effect of Treg-derived Areg in the CNS, we saw an unexpected decrease in IFN-γ production by CD4+ T cells (Fig. 5f) and corresponding increase in brain CFU (Fig. 5g) in Aregflox/floxFoxp3Cre-ERT2 mice at a late infection stage.