OKT3 pretreatment allows establishment of long-term hematopoietic xenografts from unfractionated UCB. (A) A representative hetastarch-depleted UCB, showing average and standard deviation (14 unique UCBs) stem and progenitor (CD34⁺), NK (CD56⁺), B (CD19⁺), T (CD3⁺), and myeloid (CD11b/13/14/16/33⁺) cells. Units contained an average of 850 M WBCs with average recovery of 84% (±11%). (B) One to 15 million total UCB-WBCs were infused, and NSGS and NRGS mice were followed for GVHD. Samples were pretreated with OKT3 (solid lines, right) or control (dashed lines, left). (C) Mice injected with UCB cells were followed for engraftment of hCD45⁺ cells in the PB. Plots show average levels from 2 unique UCBs in 2 experiments (1 and 2) utilizing NSGS (1) and NRGS (2) mice. (D) Average PB lineage distribution of human grafts observed in the OKT3 cohorts. (E) The 12- to 16-week BM engraftment in NSG mice receiving OKT3 pretreated UCB. Data from 3 separate UCB samples engrafted into 2 or 3 mice each (n = 7) is shown. Populations are shown as percentages of the hCD45⁺ graft. (F) Secondary NSG engraftment was measured at 16 weeks in the PB and BM. Results from 4 secondary mice are shown. (G) OKT3 pretreated WUCB engraftment of 3 NSG mice was measured at 12 weeks and again at 20 weeks to determine the potential for long-term engraftment. (H) BM engraftment in mice that received 1 to 5 million WBCs from unique fresh or frozen UCB units. Each column represents the average from 3 to 9 mice at 10 to 12 weeks.