Loss of AML1-ETO–expressing GFP+ cells from culture after transduction of human HPCs.
(A) Transduced HPCs grown in cytokine-driven culture were monitored for expression of GFP protein weekly for 5 weeks. Cells were cultured in complete media with cytokines, counted weekly, and replated at 1 × 105 cells per milliliter. A representative experiment is shown. (B) Decrease in GFP-expressing cells during the first week in cytokine-driven culture, shown as the percentage of loss in GFP-expressing cells (from 3 independent experiments). (C) Fold expansion of GFP-expressing cells over a 4-week period in cytokine-driven culture. (D) Total fold expansion of cells during the same time period shown in panel C. The inset in panel D represents the average total cumulative fold expansion. Cells were counted weekly by trypan blue dye exclusion, and the percentage of GFP expression was determined by flow cytometry. Results are the average of 2 independent experiments. MIGR1 represents cells transduced with the empty retroviral vector. MIGR1-AE represents cells transduced with the AML1-ETO–expressing retrovirus.
