CD4 and infection: Although Tim-3 expression on CD3+CD4+ Th cells decreased at day 9 post-infection, it remained higher (but not significantly) than that on day 3 post-infection (Figure 3A, left, day 3 vs. day 9: 2.20 ± 0.52 vs. 2.87 ± 0.21, P > 0.05), and the proportion of splenic CD3+CD4+ Th cells at day 9 post-infection was significantly lower than that on day 3 post-infection (Figure 3B, left, day 3 vs. day 9: 39.00 ± 2.21 vs. 20.30 ± 2.16, P < 0.001) in the ME49 group.