Quantitative analysis of SRCs derived from CD34⁺CD38⁻Lin⁻ cells isolated from G-CSF– or G-CSF plus SCF–mobilized PB.

Summary of human cell engraftment in NOD/SCID EMV^null mice that received transplants of G-CSF–mobilized CD34⁺CD38⁻Lin⁻ cells (Ai) or G-CSF plus SCF–mobilized CD34⁺CD38⁻Lin⁻ cells (Bi). Cells were transplanted into the tail vein of sublethally irradiated NOD/SCID mice at the dose ranges indicated. Mouse BM cells were extracted 6 to 8 weeks after transplantation, filtered, and stained with human CD45 and CD38 antibodies conjugated to fluorochromes to detect the presence or absence of human cells by flow cytometry. Each symbol (▪) represents a single mouse recipient with CD34⁺CD38⁻Lin⁻ transplanted cells derived from a total of 11 independent G-CSF–mobilized samples (n = 35) and 10 independent G-CSF plus SCF–mobilized samples (n = 32). Sorting gates and quadrants were established by means of isotype controls for each experiment. Human engraftment was observed with as few as 1000 G-CSF–mobilized CD34⁺CD38⁻Lin⁻ cells. LDA revealed that 1 SRC was present in approximately 7200 G-CSF–mobilized CD34⁺CD38⁻Lin⁻ cells (range, 3800-13 900 cells). Human engraftment was not detectable from G-CSF plus SCF CD34⁺CD38⁻Lin⁻ cells at doses up to 500 000 cells. Representative Southern blot analysis is depicted as G-CSF–mobilized MNCs and CD34⁺CD38⁻Lin⁻ cells (Aii), and G-CSF plus SCF–mobilized MNCs and CD34⁺CD38⁻Lin⁻ cells (Bii). Human engraftment exceeding 0.1% human DNA was compared with human-to-mouse DNA controls.