Consistently, more CD3+ CD4+ T cells, but not CD8+ T cells, were found to display an effector memory phenotype (CD3+CD4+CCR7−CD45RA−CD62L−) at day 11 post infection in the spleen of stat1loxP/loxP/Vav-cre mice (Fig. 4b and Supplementary Fig. 3a). Here, CD4 is linked to infection.