LSK CD34⁺Flt3^hi LMPPs provide rapid and sustained B- and T-cell engraftment of fetal X-SCID recipients. (A) Sorting strategy and purity of sorted Lin⁻SCA-1⁺KIT⁺CD34⁺FLT3^hi LMPPs and Lin⁻SCA-1⁺KIT⁺CD34⁻FLT3⁻ HSCs. Numbers in gates/quadrants indicate mean frequencies of total BM cells. (B-D) LMPPs (1000 or 200) and HSCs (200) were transplanted to fetal X-SCID recipients. PB analysis was performed at 4, 6, and 16 weeks after transplantation. (B) Donor-derived total reconstitution as percentage of total nucleated cells. Indicated above bars are frequencies of mice reconstituted (> 0.1% for each parameter) by transplanted test populations at the analysis time point, of all mice analyzed. (C) Donor-derived B lymphocytes as percentage of total PB cells. (D) Donor-derived T lymphocytes as percentage of total PB cells. All bar graphs represent mean (SEM) reconstitution levels of positively reconstituted mice. Statistical significance in reconstitution levels between LMPP and HSC transplanted recipients was evaluated, comparing only reconstituted mice, as well as comparing all recipients alive (positive and negative for reconstitution) at analysis time point (P values within parentheses). ***P < .001; **P < .005; *P < .05.