Purified Lin–hCD34+hCD38– CB cells reconstitute hematopoiesis via physiological intermediates, and display long-term reconstitution in the NOD/SCID/IL2rγnull newborn system. (A) Serial evaluation of chimerism of human cells in peripheral blood of recipient mice injected with 2 × 104 Lin–hCD34+hCD38– CB cells. White, gray, and black dots represent 3 individual recipients. (B) hCD34+ cells purified from a primary recipient marrow (left) were successfully engrafted into the secondary newborn recipients. hCD19+ B cells (middle) and hCD3+ T cells (right) in a representative secondary recipient is shown. (C) The Lin– bone marrow cells contained hCD34+hCD38+hCD10+hCD127 (IL-7Rα)+ CLPs (top row). In the Lin–hCD10–fraction, hCD34+hCD38+hCD45RA–hCD123 (IL-3Rα)lo CMPs, hCD34+hCD38+hCD45RA+hCD123lo GMPs, hCD34+hCD38+hCD45RA–hCD123– MEPs were present. Each number for progenitors indicates percentages of hCD45+ cells. SSC indicates side scatter. (D) Colony-forming activity of purified myeloid progenitor population in the methylcellulose assay. Representative data from 1 of 3 recipients are shown. Error bars represent standard deviation.