Surface expression of an interleukin-4Rα/GP Ib-IX receptor on the surface of Chinese hamster ovary cells.

A stable CHO cell line containing inducible human GP Ibβ and GP IX cDNAs was generated using tetracycline-responsive elements (see “Materials and methods”). Transfection of this cell line with the coding sequence for the IL-4Rα/GP Ibα subunit under the control of a CMV promoter generated a cell line with constitutive expression of IL-4Rα/GP Ibα and inducible expression of GP Ibβ and GP IX. Shown is the fluorescence profile of an anti–IL-4R monoclonal antibody with repressed GP Ibβ and GP IX gene expression (Tet-On) and induced GP Ibβ and GP IX expression (Tet-Off). An approximate 10-fold increase in mean fluorescence produced by the IL-4R monoclonal antibody is generated by the simultaneous expression of GP Ibβ and GP IX. Nontransfected CHOs (Neg CHO) are shown for comparison.