CCR2 requirement for recruitment to selectively control growth of ΔyopM Y. pestis KIM5. WT and CCR2−/− C57BL/6 mice were infected and analyzed as described in the legend for Fig. 1 for bacterial burdens and inflammatory leukocyte populations in livers and spleens on day 3 p.i. P/WT, WT mice infected with parent Y. pestis; M/WT, WT mice infected with the ΔyopM mutant; P/CCR2−/−, CCR2−/− mice infected with the parent strain; M/CCR2−/−, CCR2−/− mice infected with the ΔyopM strain. Ly6G− CD11b+ cells (MOs, Mφs, and myeloid DCs) (A) and PMNs (Ly6G+ CD11b+ cells) (B) are expressed as percentage of total live leukocytes. (C) CFU. Each datum point represents the average of values from 9 mice. The error bars indicate the standard deviations. In comparisons between WT and CCR2−/− mice, ψψ, P < 0.01 for mice infected with the ΔyopM strain; δδ, P < 0.01 for mice infected with the parent strain. In comparisons between groups of mice infected with the ΔyopM and parent strains, **, P < 0.01 for WT mice; #, P < 0.05, and # #, P < 0.01, for CCR2−/− mice.