CD4 and infection: Results indicated that the number of CD8+ T cells decreased significantly by about 50% at 4 dpi (253.74 ± 178.58, P = 0.0427) compared to uninfected baseline (day 0, 574.37 ± 241.20), then increased sharply (Figure 3B), while the number of CD4+ T cells showed nonsignificant changes during infection (Figure 3C).