Me6 mobilizes HSCs with long-term repopulating capacity. (A) Survival rate analysis of the recipient C57BL/6 mice that were transplanted with PB MNCs of donor C57BL/6 mice subjected to different treatments. The C57BL/6 donor mice were injected with PBS, 5 mg/kg Me6, or 5 mg/kg plerixafor (AMD; AMD3100). PB was collected after 12 hours for Me6-treated mice and after 1 hour for plerixafor-treated mice and transplanted into recipient mice that were lethally irradiated (800 cGy) before intravenous injection of the cells. The cells that were obtained from 1.5 mL of blood were transplanted into individual recipient mice. As a control, one group of recipient mice received cells that were obtained from normal BM, and another group of mice did not receive any cells. n = 10 mice per group. (B-C) Competitive repopulation assay. Lethally irradiated C57BL/6 mice (CD45.1) received MNCs from 2.0 mL PB from mice (CD45.2) that had received different treatments. Donor PB was collected at 12 hours for Me6-treated CD45.2 mice and at 1 hour for plerixafor-treated CD45.2 mice. Mice also received 5 × 10⁵ congenic BM competitor cells (CD45.1⁺). The results are shown as (B) the percentage of donor CD45.1⁺ cells vs recipient CD45.2⁺ cells and (C) the percent lineage of the CD45.1⁺ cells in PB of primary CD45.2 recipients 6 months after transplantation. n = 6 mice per group. **P < .01 vs the control group; ^#P < .05 vs the plerixafor group. FITC, fluorescein isothiocyanate.