Characterization of Monocyte Behavior

Wild-type C57BL/6 mice in CD45.2 background or CD45.1 background were purchased from the National Cancer Institute (Frederick, MD). CX3CR1^gfp/gfp, CCR2^rfp/rfp, CD11a^-/-, CD11b^-/-, ICAM1^-/-, Nr4a1^-/-, and TNFR^-/- mice in C57BL/6 background were obtained from Jackson Laboratory. CX3CR1^gfp/gfp mice were bred with wild-type C57BL/6 mice or CCR2^rfp/rfp mice to produce CX3CR1^gfp/+ mice or CX3CR1^gfp/+CCR2^rfp/+ heterozygous mice. The CX3CR1^gfp/gfp mice express GFP under the promoter of the CX3CR1 gene [58 (link)], which is predominantly expressed on monocytes and has been extensively used to study monocyte behavior [11 (link), 12 (link), 32 (link)]. All colonies were maintained in ventilated specific-pathogen-free facilities with standard 12 h light/dark cycles. Animals between 6 and 12 weeks of age were used for all experiments.