H/F-LVs conserve the phenotype of transduced B cells and transduce B cells preferentially over T cells. (A) Resting B cells were transduced with H/F-LVs and VSVG-LVs at an MOI of 10 and 30, respectively, or incubated without vector. Surface staining of activation markers (CD69, CD71) for day 2 after transduction is shown. Surface expression of CD86, naive (CD27⁻) and memory B-cell (CD27⁺) subsets was detected by FACS analysis (mean ± SD; n = 4). (B) The surface expression of the 2 measles receptors, hCD46 and hSLAM, was detected on nontransduced, H/F-LV– and VSVG-LV–transduced purified B cells 2 days after transduction (mean ± SD; n = 6). (C) Human PBMCs were isolated by a Ficoll gradient and transduced with either H/F-LVs or VSVG-LVs at identical vector doses as in panel A. Surface expression of SLAM receptor on adult B cells (CD19⁺) and T cells (CD3⁺) present in the PBMC population is shown directly after isolation (day 0) and after transduction with H/F-LVs or VSVG-LVs (day 3). At day 3 after transduction GFP expression was determined in the B cells (CD19⁺) and T cells (CD3⁺) present in the PBMC population by FACS analysis. These data are representative of 3 experiments.