In addition, levels of IL-6, CCL2, CCL3 and CCL5 in CCR2-/-, CCR2-/-→WT and WT→CCR2-/- mice also increased following the infection (P<0.05 (not indicated)) compared to their counterparts sacrificed on day 0 and were significantly higher than those of WT mice on day 6 (P<0.05 for all deficient groups). Here, CCR2 is linked to infection.