Experimental design.

Each animal initially received 5 doses of either G-CSF+SCF or G-CSF before leukapheresis. CD34⁺ cells were transduced with either G1Na or LNL6 vectors for 96 hours. Each animal was mobilized with the alternative regimen 6 weeks later, but this time transduction was done with the other vector. Both transduced aliquots were frozen at the end of transduction and then thawed and reinfused to the monkey after 500 cGy × 2 total body irradiation. The same experimental design was used to compare G-CSF+SCF– versus G-CSF+Flt3-L–mobilized cells.