CXCL8 and infection: The relative expression of IL-18 and IL-8 mRNA in the ΔhtpG infection group was significantly lower than that in the WT infection and CΔhtpG infection groups (p < 0.01), and the relative expression of IL-8 in the CΔhtpG infection group was significantly lower than that in the WT infection group (p < 0.05).