Binding properties of monoclonal antibodies recognizing external epitopes of the human MDR1 P-glycoprotein

Autor: Frank Baas, Igor B. Roninson, Eugene B. Mechetner, A.H. Schinkel, J. J. M. Smit, Robert J. Arceci, Els Wagenaar, Piet Borst, M. Dolle, Takashi Tsuruo
Přispěvatelé: Other departments
Rok vydání: 1993
Předmět:
Zdroj: International journal of cancer. Journal international du cancer, 55(3), 478-484. Wiley-Liss Inc.
ISSN: 1097-0215
0020-7136
DOI: 10.1002/ijc.2910550326
Popis: Monoclonal antibodies (MAbs) recognizing external epitopes of the human MDRI P-glycoprotein have been used both for the detection of multidrug-resistant cells and as specific inhibitors of P-glycoprotein-mediated multidrug resistance. Using a panel of recently developed transfected or transgenic cell lines containing variants of the human MDRI and MDR3 P-glycoproteins, we have compared the specificity and binding properties of the previously isolated MAbs MRK16, HYB-241, UIC2 and 4E3, and of the newly isolated MAb 7G4. The removal of 1, 2 or all 3 of the N-glycosylation sites present in the first extracellular loop of MDR1 P-glycoprotein did not significantly affect the binding of these MAbs. In contrast, a 20 amino acid deletion in the first extracellular loop of MDR1 P-glycoprotein completely abolished binding of UIC2, whereas the binding of all other MAbs was hardly affected. None of the MAbs tested bound detectably to cell lines containing a high level of the human MDR3 P-glycoprotein. The differences in the binding specificity between UIC2 and the other tested antibodies parallel the reported functional differences in the ability of these antibodies to inhibit P-glycoprotein-mediated drug efflux.
Databáze: OpenAIRE