CCL2 and infection: Many pro-inflammatory cytokines and chemokines were highly expressed in the PBS-vaccinated NC99-challenged primary infection mice at 3 and 7 DPC at significantly higher concentrations than all other groups: IL-1β, IL-6, IL-18, IL-22, IL-27, CCL2, CCL3, CXCL2, CCL4, CCL5, CCL7, CXCL1, and CXCL10.