Administration of anti-IL-2 mAb to WSX-1−/− mice from day 7 of infection (when Th1 responses are similar in WT and WSX-1−/− mice) failed to restrict the Th1 response; frequencies and total numbers of effector CD4+ T-bet+ T cells (Figure 5A–C), as well as frequencies and numbers of KLRG-1+ effector CD4+T-bet+ T cells (Figure 5D–F), were similar in WSX-1−/− mice treated with anti-IL-2 and control (untreated) WSX-1−/− mice. This evidence concerns the gene CD4 and infection.