Lentiviral vector mediated transgene expression in less-differentiated cells. A, Diagram of hypothetical FACS of PBL using anti-CD62L and CD45RO. EM, effector memory; CM, central memory; naïve T cells. B, C, Transduced PBLs activated via anti-CD3/CD28 bead or OKT3 was analyzed for CD62L and CD45RO at day 15. The number in each plot represents the percentage of cells in each quadrant. Three histograms indicated by arrows display the percentage of MART-1TCR positive cells in each quadrant. D, E, PBLs were transduced with lentiviral vector in D or gamma-retroviral vector in E. PBLs were activated using OKT3, with transduction at day 1. FACS was performed at day 7 and day 14 using CD62L and CD45RO markers and MART-1 TCR positive cells were plotted in histograms as described above.