Colonies derived from A10–GFP- and GFP-transduced progenitors.

(A) Comparison of the frequency and distribution of colonies derived from A10–GFP- and GFP-transduced progenitors in methylcellulose scored on day 14. Median frequencies of 6 independent experiments performed with 6 different cord blood samples are indicated by bars. (B) Methylcellulose dishes of primary CFC cultures derived from A10–GFP- and GFP-transduced progenitors were killed on day 14, and progenitor cells resuspended in IMDM 2% FCS were replated in secondary methylcellulose cultures. Secondary colony formation was assessed on day 14. Medians of secondary colony formation of 4 independent experiments performed with 4 different cord blood samples are indicated by bars. (C) Morphology of blast colonies was confirmed by staining individually plucked colonies with Wright-Giemsa. CFU-GEMM indicates colony-forming unit–granulocyte erythroid macrophage megakaryocyte; BFU-E, burst-forming unit–erythroid.