Purified Lin^–hCD34⁺hCD38^–CB cells reconstitute hematopoiesis via physiological intermediates, and display long-term reconstitution in the NOD/SCID/IL2rγ^nullnewborn 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⁺hCD123^lo 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.