Enhancing Antibody Fc Heterodimer Formation through Electrostatic Steering Effects: APPLICATIONS TO BISPECIFIC MOLECULES AND MONOVALENT IgG |
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Authors: | Kannan Gunasekaran Martin Pentony Min Shen Logan Garrett Carla Forte Anne Woodward Soo Bin Ng Teresa Born Marc Retter Kathy Manchulenko Heather Sweet Ian N. Foltz Michael Wittekind Wei Yan |
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Affiliation: | From the Departments of ‡Protein Science.;§Inflammation, and ;¶Pharmacokinetics & Drug Metabolism, Amgen Inc., Seattle, Washington 98119 and ;‖Amgen British Columbia, Burnaby, British Columbia V5A1V7, Canada |
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Abstract: | Naturally occurring IgG antibodies are bivalent and monospecific. Bispecific antibodies having binding specificities for two different antigens can be produced using recombinant technologies and are projected to have broad clinical applications. However, co-expression of multiple light and heavy chains often leads to contaminants and pose purification challenges. In this work, we have modified the CH3 domain interface of the antibody Fc region with selected mutations so that the engineered Fc proteins preferentially form heterodimers. These novel mutations create altered charge polarity across the Fc dimer interface such that coexpression of electrostatically matched Fc chains support favorable attractive interactions thereby promoting desired Fc heterodimer formation, whereas unfavorable repulsive charge interactions suppress unwanted Fc homodimer formation. This new Fc heterodimer format was used to produce bispecific single chain antibody fusions and monovalent IgGs with minimal homodimer contaminants. The strategy proposed here demonstrates the feasibility of robust production of novel Fc-based heterodimeric molecules and hence broadens the scope of bispecific molecules for therapeutic applications. |
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Keywords: | Antibodies Cancer Therapy Immunology Protein Structure Protein-Protein Interactions Antibody Engineering Bispecific Single Chain Fv Fc Heterodimer Monovalent IgG Protein-Protein Interface Engineering |
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