CD34⁺ progenitors transduced with NA-7.ER in FTOC. Bivariate dot plots of flow cytometric measurement of Nef^– (control), NA-7– or NA-7.ER–transduced cells, analyzed at day 22 of FTOC. (A) CD8β-PE, CD4-APC versus EGFP expression of transduced thymocytes at day 22 of FTOC. (B) CD8β-PE versus CD4-APC expression from thymocytes shown in panel A, gated on EGFP⁺ cells. Quadrants were set to include 99% of cells stained with isotypic controls and EGFP^– cells in lower left quadrant. Values indicate percentage (rounded to a whole number) of cells present in corresponding quadrants. (C) Thymocyte generation ratios for the different experimental conditions as indicated and (D) for NA-7.ER, switched on at day 0 or day 5 of organ culture. Panels C and D show mean values, and their standard deviations are calculated from the data generated in at least 3 independent experiments. An asterisk (*) over a bar indicates a statistically significant lower ratio of the experimental construct compared with the control (P < .05).