Competitive repopulation assay in mice transplanted with equal donor volumes of HaMDR1- and HaDHFR^L22Y-transduced BM cells.

BM cells from C57BL/6 mice were transduced with the HaMDR1 vector, and HW80 marrow cells were transduced with the HaDHFR^L22Yvector. Immediately after the transduction, equal donor volumes from each transduced graft were mixed and transplanted into lethally irradiated recipient mice. Engraftment was monitored by tracking the proportion of donor hemoglobin specific for either the HaMDR1-transduced (lower band) or the HaDHFR^L22Y-transduced (upper 2 bands) cells. (A) Hemoglobin electrophoresis gels are shown for mice from experiment 2, obtained at 7, 14, and 24 weeks after transplantation. These mice were divided into 2 groups. One received two 5-day courses of G-CSF/SCF treatment (left), and the other was the untreated group (right). Each lane represents a sample from a single mouse. The hemoglobin pattern for the C57BL/6 and HW80 controls are shown on the right. (B) Two independent mixing experiments were performed, and the data for both of these are graphically shown. The y-axis represents the percentage of donor engraftment with MDR1-transduced cells, as indicated by hemoglobin electrophoresis. Each line represents an individual mouse analyzed serially over time.