Compared with those in the infection group, the proportions of CD3+ T cells, CD4+ T cells and CD3+CD8+ T cells among splenocytes in the levamisole and BMS-1 groups were greater (P < 0.05) (P < 0.05; Figure 4B, Additional file 2, panels B3, B4; Figure 5B, Additional file 3, panels B3, B4; Figure 6B, Additional file 4, panels B3, B4). Here, CD4 is linked to infection.