The H/F-displaying lentiviral vectors efficiently transduce quiescent and proliferating B cells. (A) Schematic representation of the lentiviral vectors displaying hemagglutinin (H) and fusion (F) glycoproteins derived from Edmonston strain MV. The combination of the cytoplasmic-tail mutants of MV glycoproteins, HΔ24 and FΔ30, allowed efficient coincorporation on the LV surface, resulting in high-titer HIV vectors (hereafter named H/F-LVs). These H/F-LVs conserved the parental tropism as confirmed by transduction of CD46⁺ and SLAM⁺ cell lines.¹²  (B) Adult B cells were prestimulated for 24 hours with SAC/IL-2, and cell-cycle progression was monitored by simultaneously visualizing RNA (pyronin-Y) and DNA content (7-AAD; left). The percentages of cells in the G₀/G₁a, G₁b, and S/G₂/M phase of the cell cycle are indicated in the dot plot. Surface staining of SLAM by FACS is shown (right, open histogram). Closed histograms represent staining with IgG isotype controls. The percentage and mean fluorescence intensity (MFI) of SLAM-expressing cells are indicated. (C) Percentage of GFP measured by FACS at day 2 after transduction of SAC/IL-2 prestimulated B cells transduced with H/F-LVs (MOI = 10) and VSVG-LVs (MOI = 30; representative data of 5 experiments). (D) Adult B cells were verified for their quiescent state on isolation by PY/7-AAD staining as in panel B, and surface staining of SLAM by FACS is shown. (E) Percentage of GFP expression and (F) pyronin-Y/ 7AAD cell-cycle analysis at day 2 after transduction of adult resting B cells transduced as in panel C (representative data of 5 experiments).