Competitive repopulation studies using cells transduced with the HaMDR1▵34 vector.

(A) Hemoglobin electrophoresis of 12-day expanded cells competed against fresh bone marrow cells. C57BL/6 cells were transduced with either the HaMDR1 vector (left lanes) or with the HaMDR1Δ34 vector (right lanes) and competed against fresh HW80 bone marrow cells at a femur volume ratio of 0.02 transduced to 0.25 fresh. Sixteen weeks after transplantation into irradiated recipient mice, hemoglobin electrophoresis was performed to monitor engraftment from the 2 donor sources. Each lane represents the results from an individual transplanted mouse. (B) PCR analysis of DNA from peripheral leukocytes of mice transplanted with equal volumes of HaMDR1 and HaMDR1Δ34-transduced marrow. The single primer set was used that flanked the Δ34 deletion and amplified a 692-bp and a 590-bp fragment from the HaMDR1 and the HaMDR1Δ34 proviral genomes, respectively. From the left, the first lane is from a mock-transduced mouse, the second lane from a mouse that received only HaMDR1Δ34-transduced cells, and the third lane from a mouse that received only HaMDR1-transduced cells. The remaining lanes are from 2 independent experiments in which mice were transplanted using 0.02 femur volumes from each expanded graft. The 3 mice in the first experiment were analyzed 11 weeks after transplantation, and the last 6 lanes are from mice from a second experiment analyzed 18 weeks after transplantation.