IL-15 suppresses CX3CR1 expression in mouse bone marrow-derived NK cells in a dose-dependent manner. Freshly harvested bone marrow from wild-type C57Bl/6 mice (A-B) and from CX3CR1-/- C57Bl/6 mice (B) was cultured according to the protocol in Figure 2, varying the concentration of cytokine. Samples were then analyzed for CX3CR1 and control protein and RNA content as in Figure 2. The same cell cultures were also examined for accumulation of CCR5 and CXCR4 transcripts. (B) The legend for the CXCR4 and CCR5 panels is identical to the CX3CR1 panel, with the exception of the positive control tissue, as noted. (C-D) Densitometric analysis of results shown in panels A and B, respectively. Results shown are from a single experiment representative of at least 3 separate experiments.