CD4 and infection: To address this, CD4+CD25+ Treg cells were isolated from either C. albicans-infected or uninfected control B6.Foxp3hCD2 mice (preexisting Treg-cell phenotype), labeled with carboxyfluorescein succinimidyl ester (CFSE) and co-cultured with unlabeled, Treg-cell-depleted SMCs from infection-matched WT C57BL/6 mice (Teff cells).