CD4 and infection: In contrast, no significant differences were observed in the frequencies or absolute numbers of CD4+Foxp3- or CD8+ T cells and their levels of CD44 expression on day 25 post-infection; however, on day 46 post-infection, the percentages of CD4+Foxp3-CD44hi T cells were higher in IFNARfl/fl x Foxp3YFP-Cre mice (S2A–S2D Fig).