CXCR4-dependent engraftment of human CD34⁺ cells.

(A) BM engraftment of NOD/SCID mice, by enriched human CD34⁺ cells derived from peripheral blood of G-CSF–treated donors (MPB) or BM aspiration of healthy donors. BM of mice that underwent transplantation was harvested 1 month later; human/mouse chimerism was determined by flow cytometry using antihuman-specific CD45-FITC mAb. Human CD34⁺ cells (2 × 10⁵cells/mouse) were transplanted without (●) or with (○) anti-CXCR4 mAb (10 μg/mouse). Each dot represents one mouse. Data summarize results of 3 independent experiments. P values are indicated. (B) CB enriched CD34⁺ cells (Bi) were further sorted with neutralizing antihuman CXCR4 mAb to R4⁺ (Bii), and R4⁻ (Biii) purified subsets. (C) Murine BM engraftment of CB CD34+ subsets. Enriched CD34⁺ subset cells were pretreated and coinjected as described for panel A. Data summarize results of 4 independent experiments. P values are indicated. (D) Dose-dependent inhibition of BM repopulation by anti-CXCR4 mAb. Dose-dependent activity of 12G5 mAb is demonstrated by coinjecting 10 μg/mouse versus 50 μg/mouse. Human cell engraftment in the murine BM is presented. ■ indicates untreated CD34⁺ cells. ░ indicates coinjection of 10 μg/mouse. ▪ indicates coinjection of 50 μg/mouse or background levels determined by staining with isotype control mAb, as indicated.P values are indicated. Data present values of 3 experiments.