The percentage of human cell chimerism following transplantation of reisolated CD34⁺CD90⁺ cells that have undergone 5 or more cell divisions following ex vivo culture. CD34⁺ cells cultured in the presence of cytokines with or without 5azaD/TSA treatment were harvested after 9 days; the CD34⁺CD90⁺ cells that have undergone 4 or fewer divisions and 5 or more divisions were reisolated, then injected into NOD/SCID mice. (A) NOD/SCID (n = 21, data pooled from 2 independent experiments) engraftment achieved with CD34⁺CD90⁺ cells (≤ 4 divisions and ≥ 5 divisions). The percent of human hematopoietic cell chimerism is plotted as dots and their mean values indicated as horizontal bars. (B) Representative flow cytometric analysis of multilineage hematopoietic differentiation potential of engrafted human hematopoietic cells in NOD/SCID mice given transplants with reisolated CD34⁺CD90⁺ cells (≥ 5 divisions) is shown. *Previously published data, reprinted with permission.²⁴