Based on the importance of neutrophils and monocytes in controlling bacterial burdens during early E. coli K1 meningoencephalitis, we measured IL-6 and IL-10 as key cytokines of the innate defense system during infection and the chemokines CXCL1 (KC) and CXCL2 (MIP-2) as key players in the recruitment of neutrophils into the CNS [30,31]. This evidence concerns the gene CXCL2 and infection.