Human hematopoietic engraftment to NOD/SCID bone marrow. NOD/SCID mice received 1000 or 3000 transplanted SSC^lo ALDH^br CD34⁺ cells each. Comparisons were drawn to mice that received transplanted SSC^lo ALDH^neg CD34⁺ or SSC^lo ALDH^br CD34^neg cells (3000 or 10 000 cells per transplant). Transplantation controls included mice that underwent transplantation with 10 000 or 30 000 lin^neg CD34⁺ cells. (A) Human hematopoietic engraftment was assessed by the presence of CD45⁺ ly5^neg (murine CD45^neg) cells in NOD/SCID bone marrow. (B) To confirm engraftment, some marrows were enriched for human cells by depletion of lineage-committed murine cells using density-dependent negative selection. Percentages indicate the % CD45⁺ cells. (C) IgG indicates immunoglobulin G. Human hematopoietic engraftment was determined for (D) B-lymphoid, (E) myeloid, and (F) CD34⁺ progenitor cells. (A-F) Analyses performed at 20 to 21 weeks after transplantation of mice that underwent transplantation with 3000 SSC^lo ALDH^br CD34⁺ cells (A-B) or with 3000 lin^neg SSC^lo ALDH^br CD34⁺ cells (C-F). The percentage of long-term human hematopoietic engraftment for each cell fraction is depicted in panel G (as labeled; 18 to 21 weeks after transplantation; n = 6 UCB). The percentage of short-term human hematopoietic engraftment for each cell fraction is depicted in panel H (as labeled; 6 to 7 weeks after transplantation; n = 3 UCB). Each data point represents the percentage of human hematopoietic engraftment within a single mouse.