Quantitation of SP cell expansion in cultures of cells transduced with the HaMDR1▵34 vector.

BM cells were transduced with either the HaMDR1Δ34 (A, C) or the HaMDR1 vector (B, D) and then were expanded in suspension cultures for the indicated time periods. (A, B) SP cell analyses performed after 7 days of expansion. (C, D) A second independent experiment analyzed after 13 days of culture. The percentage of cells in the SP cell gate is indicated in each panel. In experiment 2, propidium iodide was added before flow cytometry analysis to exclude dead cells from the initial gated population.