PPIB and infection: Similarly, phenotypes of effector CD4+ T-bet+ T cells from WT and WSX-1−/− mice were similar on day 9 of infection, with the notable exception of CD25 (IL-2Rα), IL-18R and CD226 which were all expressed at significantly higher levels on cells from WSX-1−/− mice, and B and T lymphocyte attenuator (BTLA), which was expressed at lower levels on cells from WSX-1−/− mice (Figure 3A–D).