Clonogenic progenitor and CD34⁺/CD38^-/low content of transduced CD34⁺ cells. Transduced CB CD34⁺ cells were seeded in semisolid methylcellulose culture. (A) GFP⁺ CFC colonies were analyzed by phase contrast microscopy at × 10 original magnification on day 14. Top panel indicates BFU-E (i) and CFU-GM (ii) colonies from control cells. Bottom panel indicates BFU-Es (iii) and CFU-GMs (iv) from CXCR4-transduced cells. A representative experiment is shown. (B) Data indicate total number of CFU-GM and BFU-E colonies. Numbers above bars indicate percentage of GFP⁺ colonies out of total colonies. Bars represent mean ± SE of 3 independent experiments. ^*P = .004 compared to BFU-E colonies of control cells. (C) CB and MPB CD34⁺ cells were labeled with human anti-CD34 and anti-CD38 mAbs. Numbers indicate percent positive cells from entire population. A representative experiment of 3 is shown.