Furthermore, we detected the ratio of splenic PD-1+ CD8+ T cells to total CD8+ T cells in ECM mice from 0 day post-infection (dpi) to 10 dpi (Figure 1G) and found that the ratio of PD-1+ CD8+ T cells rose after infection (6.0%) and peaked (22.8%) at 5 dpi. The gene discussed is PDCD1; the disease is infection.