Lentivector but not oncoretrovirus MFGS-vector efficiently transduced G₀-sorted CD34⁺PBSCs.

CD34⁺PBSCs were sorted for the G₀ cell-cycle phase using Hoechst 33342 (DNA dye) and Pyronin Y (RNA dye) 18 hours after the initiation of culture in proliferation-permissive growth medium. The gate for sorting G₀ cells (low DNA, low RNA content) were selected as depicted in panel A. Postsort analysis (B) confirms the accuracy of the cell-sorting procedure. Sorted G₀ CD34⁺PBSC cells were cotransduced with lentivector–CFP and MFGS–GFP at 24 hours and 48 hours after sorting and were analyzed on day 10 by flow cytometry. Gates were drawn according to simultaneously performed single lentivector–CFP and MFGS-GFP transductions on unsorted (E,F) and naive CD34⁺PBSCs (C). Although the MFGS vector achieved higher transduction levels in the unsorted population (25% vs 19%), the lentivector outperformed the MFGS vector in transduction of the G₀ sorted cells (D).