CCR1 is highly expressed in monocyte/macrophages and facilitates migration. (A-B) The bioinformatics analysis demonstrates CCR1 expression on various immune cells in the BM and PBMC. (C-D) The expression of CCR1 or CCR5 in human-Mo (C) and murine-macrophages (D) was measured using flow cytometry using specific antibodies. (E) The number of peritoneal cells collected from WT and CCR1-/- mice after thioglycolate in vivo treatment in the peritoneal cavity (n = 5). (F) BMDM from WT or CCR1-/- C57/BL/6NJ mice (n = 5) were incubated with CM collected from FC-muMCL1, and the migration was assessed using chemotaxis assay. (G) BMDM from WT or CCR1-/- mice (n=5) were incubated with 100 ng/mL rCCL3 in vitro, and the migration was assessed using a chemotaxis assay. The data presented are representative of 3 independent experiments (∗P < .05). (H-I) Immunofluorescent staining was performed on the syngeneic mouse tumor–bearing lymphoma using Ly6C (green) and CCR1 (red) antibodies. The experiment was performed on 3 mouse tumors and representative data are shown along with quantification. Nuclei were stained with DAPI (blue). (J-K) Mino (J) or Granta (K) CM treated with vehicle or indicated concentrations of CCR1 antagonist (BX-471), CCR4 antagonist (AZD2089), or CCR5 antagonist (Maraviroc) for 48 hours were used to attract THP1-Mo in a chemotaxis assay. (L) MCL (Mino, Granta, or JVM2) CM was used to attract CD14⁺ Mo transfected with CCR1 or control siRNA. The data presented are representative of 3 independent experiments (∗∗P < .01; ∗∗∗P < .001).