On day 14 p.i., total virus infection-induced (CD44hiCD11ahi) and epitope-specific (GP61-80) effector CD4 T cells showed marked reductions in both the proportion of Blimp-1-eYFP+ cells (S2B Fig) and per-cell expression of Blimp-1-eYFP (S2C Fig) following administration of α-IFNAR to LCMV clone 13-infected mice. This evidence concerns the gene PRDM1 and viral infectious disease.