CD4 and infection: In the first week after infection, FoxP3 expression is lower while T-bet expression is higher on activated CD4+ T cells in μMT mice (Fig 3B and 3C); however, we found expression of FoxP3 and T-bet was similar in activated CD4+ T cells from B cell MHCII deficient mice and control animals one week post-infection (S7A–S7C Fig).