PRDM1 and infection: WT (Prdm1+/+ROSA26-Cre-ERT2; Thy1.1/1.1) and Blimp1–/– (Prdm1fl/fl ROSA26-Cre-ERT2; Thy1.1/1.2) naïve P14 CD8+ T cells were co-transferred into B6 mice and tamoxifen administration began two days before infection with VacV (+/- Ag) on the left and right ear skin (Fig. 6a).