In vivo multilineage reconstitution and GFP expression of CXCR4-overexpressing SRCs. CXCR4-transduced CB CD34⁺ cells were injected into sublethally irradiated NOD/SCID mice. Five weeks after transplantation mice were examined for the presence of repopulating human cells when compared to control GFP-transduced cells. (A) Murine BM (i), spleen (ii), and peripheral blood (PB; iii) were analyzed for human cell engraftment by FACS analysis of % of human CD45⁺ cells. Bars represent mean ± SE of 9 independent experiments performed in duplicate or triplicate. ^*P < .005 compared to control GFP-transduced cells. (B) Lymphoid and myeloid differentiation of human SRCs in a representative NOD/SCID transplant recipient is shown by CD19 and CD33 antibody staining, respectively. Numbers indicate percent of positive cells of total live population. (C) BM cells were stained for the human-specific pan leukocyte marker CD45 and the B-cell lineage differentiation marker CD19 and analyzed by FACS. Numbers indicate percentage of CD19 cells calculated from total CD45 population. Data show a representative experiment. (D) BM cells were stained with human-specific anti-CD34 and anti-CD38 mAbs and analyzed by flow cytometry. Numbers indicate percentage of CD34⁺/38^-/low cells. Data show a representative experiment. (E) Homing of cells to the spleen was determined 16 hours (MPB) or 2 hours (CB) after transplantation by staining with human-specific anti-CD34 and anti-CD38 mAbs. Bars represent mean ± SE of 3 independent experiments performed in duplicate. ^*P < .05 compared to control cells.