Freshly isolated CD34⁺ or cultured cells (unstained and PKH26-labeled) were infused into sublethally irradiated NOD/SCID mice. Cultured cells were stimulated with SCF (100 ng/mL), FL (100 ng/mL), IL-3 (20 ng/mL), and IL-6 (20 ng/mL) in X-VIVO 10 with 1% HSA for 48 hours. For each experiment, homing was assessed 24 hours after transplantation by flow cytometric analysis of BM cells, as detailed in “Materials and methods.” Data for the homing of cells has been presented here as number of positive events per million BM cells analyzed. Data are given for each animal from 2 independent experiments. Mice in experiment 1 were nonirradiated.