Engraftment potential of CD34⁺ cells and nonadherent CD34⁻ cells.

(A) Eight weeks after intravenous injection of NOD/SCID mice with 5000 NA CD34⁻ cells or 5000 CD34⁺ cells, bone marrow cells were analyzed by flow cytometry with antibody to human CD45, without gating. Graph shows the percentage engraftment in 10 recipients of NA CD34⁻ cells produced in vitro by stimulation of adherent cells with SCF for 72 hours (▪), 8 recipients of freshly isolated CD34⁺ cells (■), 6 recipients of freshly isolated CD34⁺ cells that had been stimulated in vitro with SCF for 72 hours (●), and 6 mice that received only injections of PBS (○). (B) Effect of cell dose on engraftment potential of NA CD34⁻ cells in NOD/SCID mice. The percentage of human cells in the bone marrow of 40 recipients was determined 8 to 10 weeks after transplantation by flow cytometric analysis of human CD45 expression. (C) Analysis of DNA isolated from the bone marrow cells of recipients in panel B. The levels of human DNA were compared with the values of human-mouse control mixtures. The results are given as the means ± standard deviations of 3 PCR-ELISA measurements.