Cell-dose limiting dilution of transduced CB CD34⁺cells (TU 50 × 10⁶/mL or MOI 50). Cells at the indicated doses were preincubated for 4 days with FL, TPO, SCF, and IL6; incubated overnight with viral particles; and subsequently grown with the same growth factors for a total of 4 weeks. All progeny cells were harvested and inoculated into sublethally irradiated NOD/SCID mice. The mice were killed 6 to 8 weeks after transplantation and the harvested BM was assessed for levels of human engraftment and percentage of GFP-expressing cells. Five to 15 million unfractionated BM cells from each primary mouse were inoculated into a single secondary sublethally irradiated NOD/SCID mouse, which was killed 6 to 8 weeks later.

Multilineage engraftment (ME) was defined by the presence of CD19⁺, CD34⁺, CD14⁺, CD33⁺, and CD41⁺ cells within the CD45 gate and by anti–glycophorin-A⁺ cells in the total BM.

ND indicates not done.