Similarly, CXCL1 and CXCL2 quickly increased in the early stages of GBS infection, while a significant difference in these two factors in WT and Fpr2-/- can be detected at 1 hour and 3 hours for both i.v. and i.p. infection route, which is consistent with that of the neutrophils increase. This evidence concerns the gene FPR2 and infection.