P-gp expression and function in producer cells transduced with the HaMDR1▵34 vector.

Monoclonal antibody 4E3 was used to detect cell surface expression of P-gp in GP-E86 cells transduced with the HaMDR1 vector (A) or with the HaMDR1Δ34 vector (B). The heavy line represents results from the producer cell lines, whereas the lighter lines show negative controls using nontransduced GP-E86 cells. Molecular pump function was also assayed in these cells using a rhodamine exclusion assay (C-HaMDR1, D- HaMDR1Δ34). The presence of cells with low fluorescence indicates rhodamine efflux activity caused by P-gp expression. Again, the light lines are nontransduced negative controls.