CD4 and infection: To further characterize changes in antiviral CD4 T cells in the absence of IL-27R signaling during MCMV infection, we phenotyped polyclonal CD11a+CD49d+ CD4 T cells at multiple time points post infection in the blood and observed a dramatic increase in the proportion of cells that expressed KLRG1 in Il27ra-/- mice as early as day 14 p.i., which was maintained throughout the course of infection (Fig 3A).