Mice were treated with anti-CCR2 clone MC-21 (MC-21) or isotype antibody as described in Experimental Procedures. A, monocytes were depleted with MC-21: Left, representative flow plot demonstrating efficient depletion of monocytes. Right, total monocytes were significantly reduced in MC-21 treated animals (versus isotype treated) for both genotypes. B, Disease activity index (DAI) was determined in MC-21 or isotype treated mice over the timecourse of DSS exposure (left) and in an expanded representation for day 6 of DSS exposure (right). Dotted line indicates maximum DAI score. C, colon length was determined at day 6 following administration of DSS in MC-21 and isotype treated animals. Dotted line represents colon length of water control animals. D, total numbers of eosinophils were determined with and without monocyte depletion with MC-21. Data represent mean ± SEM n=10, *p<0.05 and **p<0.01 compared to WT isotype, WT MC-21 and G2A−/− MC-21.