CX3CR1 and colitis: Previous studies showed that increased intestinal monocytes are pathogenic in colitis models14,52,53 while macrophages are found to be protective.12,54,55 Using mice that can be selectively depleted of CX3CR1+ cells,12,13 we demonstrated that the GDAR2-2-induced protection against C. rodentium infection is CX3CR1+ MNP dependent.