At 27 h post-infection, the percentage of CD3+CD4+IL-2+ T cells in mice of E. coli group was lower than that of the control, and a statistically dramatic increase of CD3+CD4+IL-2+ T cells percentage was observed in mice of Z. morio hemolymph or gentamicin treatment group relative to mice of E. coli group (Figure 2G). This evidence concerns the gene CD4 and infection.