On the 10th day after the infection of rats with APID, the ratio of CD4+T cells secreting IL-4 in the spleen of rats in the APDI + irisin group was lower than that in the APID group and the ratio of CD8+T cells secreting IL-4 in the spleen of rats in the APDI + irisin group was lower than that in the APID group (Figure 4(a)), while the ratio of CD8+T cells secreting IFN-γ in the spleen of rats in the APDI + irisin group was higher than that in the APID group. Here, CD4 is linked to infection.