Primary and secondary colony formation in methylcellulose.

Methylcellulose dishes of primary CFC cultures were killed on day 14 and replated in secondary methylcellulose cultures. Secondary colony formation was assessed on day 14. Mean numbers of primary and secondary colonies for 6 independent experiments with 6 different CB samples are indicated by bars (A). The morphology and increased number of macroscopic colonies with a clear erythroid component in replated methylcellulose dishes are shown from one representative experiment compared with the GFP control (B). *P < .03.