Myeloid colony-forming assay of GFP⁺ bone marrow cells isolated from control GFP- and Pax5-expressing animals. (A) Number of colonies obtained from plating 20 000 GFP⁺ bone marrow cells (P < .56). Colonies of more than 50 cells were counted as positive after 10 days in methylcellulose. (B) Representative cytospins from the in vitro grown myeloid colonies stained with Wright-Giemsa. Original magnification, × 1000.