BaEV-LVs are superior for the transduction of human CD34⁺ cells over VSVG-LVs and RDTR-LVs. (A) Schematic representation of LVs pseudotyped by BaEV-gps (BaEVTR or BaEVRLess) that bind to the amino acid transporters, hASCT1 and hASCT2, on the HSC surface. RDTR-LVs only bind to the hASCT2 receptor. Once the LVs fuse with the cell membrane of HSCs, reverse transcription of the viral RNA into proviral DNA occurs followed by its nuclear import and integration into the host genome. (B) Cord blood hCD34⁺ cells were prestimulated with SCF, TPO, and Flt3-L for 14 hours and transduced with the indicated LV pseudotypes in the presence and absence of RetroNectin at an MOI of 10. VSV-G-LV transductions were performed at an MOI of 10 or 100. GFP expression of the cells was analyzed 6 days after transduction by FACS (means ± SD, n = 5). **P < .05 when comparing BaEVgps with other pseudotypes in the presence of RetroNectin; ***P < .005 when comparing BaEVgps with or without RetroNectin. (C) Percentage of transduction of HEK293T cells by the indicated LV pseudotypes on their incubation at 37°C in heat complement-inactivated or fresh human sera. Data for 3 different serum donors are shown. The stability of virions was calculated as the relative percentage of infectivity of macaque/human serum-treated viruses vs viruses treated with fetal calf serum set to 100%.