Rapid and selective homing of primitive CD34⁺CD38^−/low cells.

(A) Human PKH26⁺ cells in the BM, spleen, and lungs of transplanted NOD/SCID mice recovered at indicated time points after transplantation. Data represent mean ± SE from 6 experiments, n = 5 mice/time point. (B) Enriched human CD34⁺ cells before transplantation. Gate R2 represents CD34⁺CD38^−/low cells. (C,D) CD34/CD38 staining of cells recovered from the BM and spleen of mice that were transplanted with unlabeled CD34⁺-enriched cells. (C) NOD/SCID mice: (i) noninjected mouse, (ii) 2 hours after transplantation. (D) NOD/SCID/B2m^null mice: (i) noninjected mouse, (ii) 1 and 2 hours after transplantation. (E) CD34/CD38 staining of cells recovered from NOD/SCID mice, 16 hours after transplantation with sorted 2 × 10⁵CD34⁺CD38^−/low or 8 × 10⁵ CD34⁺CD38⁺ cells. Data shown represent the number of human CD34⁺CD38^−/low cells per 10⁶ total acquired cells. The experiment was repeated 3 times, showing similar results (P < .05); a representative flow cytometry analysis is shown. Homing cell numbers are presented per 10⁶ acquired cells.