Fig. 6. Dynamic CCR2 signaling regulates BM niche occupancy.

(A) Experimental schematic of competitive transplantations (1:1 donor ratio) using CD45.1/.2 WT versus Ccr2^gfp/gfp BM (n = 7). Recipient CD45.1 mice were lethally irradiated 24 hours before transplantation. A control cohort (n = 3) using CD45.1/CD45.2 WT versus CD45.2 WT BM was also analyzed. (B) PB chimerism of WT and Ccr2^gfp/gfp grafts in individual mice after transplantation. (C) PB lineage analysis at 12 weeks after transplantation. (D) Representative flow cytometric plots and quantitative analysis of CCR2⁺ and GFP⁺ donor cells and (E) BM KSL in experimental cohort animals 12 weeks after transplantation. (F) Experimental schematic of noncompetitive Ccr2^gfp/gfp GFP⁻ versus GFP⁺ graft transplantations. (G) Representative flow cytometric plots and quantitative analysis of GFP positivity in BM 20 hours after transplantation from initial GFP⁻ versus GFP⁺ grafts. (H) Flow cytometry measurement of overall donor cell BM frequency. Experimental schematics created using BioRender. *P < 0.05, **P < 0.01, and ***P < 0.001.