Decreased CCL3 binding and CCL3-induced biologic responses in CCR2-deficient resident peritoneal cells. Resident peritoneal cells were assayed for CCL3 binding as described and the macrophage population was gated (A; solid oval). Plots of an unstained sample (B), wild-type cells (C), and Ccr2^−/− cells (D) are shown. Similar to the previous results, a higher number of CCL3-bound cells was found in wild-type cells (C) compared with Ccr2^−/− resident peritoneal cells (D,E). Ccr2^−/− cells also exhibited a defective migratory response to CCL3 (F) but not to CXCL12 (not shown). Bars show mean value with SD in panels E and F. Each point in panel E represents an individual mouse. Each point in panel F represents the mean of 2 independent experiments.