AML1-ETO-expressing CD34⁺ cells retain B lymphocyte and myeloid differentiation potential. (A) Cells sorted for CD14 and CD34 expression by FACS were incubated with opsonized Texas-Red-labeled bacteria as recommended by the manufacturer. Cells were visualized by light microscopy, and for uptake of bacteria by fluorescent microscopy. (B-C) CFU-Mk colony assays were performed using CB CD34⁺ cells (as control) and long-term AML1-ETO-expressing cells according to standard procedures. After 12 days, slides containing CFU-Mk colonies were fixed and stained for CD41 expression. Colonies of greater than 8 cells were counted. The average and SD of duplicate slides are shown. (D) Cells were cultured on the MS-5 stromal cell line with 10 ng/mL Flt3L, SCF, and IL-7. Cultures were demidepopulated weekly. After 4 weeks, suspension cells were collected and CD19⁺ cells were isolated by magnetic bead selection. Flow cytometry was performed with the indicated antibodies as previously described. Original magnification, ×400 (A-B).