IL-15 and IL-2 differentially regulate CX3CR1 expression in mouse peripheral blood-derived PBMCs. PBMCs were cultured in vitro for 12 hours in the presence or absence of the indicated cytokines and neutralizing mAbs or isotype controls. Skeletal muscle protein extract was used as a negative control. Cells were then lysed and analyzed by Western blot using the antibody indicated to the right of each panel. Each lane represents a pool of PBMCs from 5 C57Bl/6 mice. Results are representative of 2 independent experiments.