title: Routes to improve binding capacities of affinity resins demonstrated for Protein A chromatography.
abstract: Protein A chromatography is a well-established platform in downstream purification of monoclonal antibodies. Dynamic binding capacities are continuously increasing with almost every newly launched Protein A resin. Nevertheless, binding capacities of affinity chromatography resins cannot compete with binding capacities obtained with modern ion exchange media. Capacities of affinity resins are roughly 50% lower. High binding capacities of ion exchange media are supported by spacer technologies. In this article, we review existing spacer technologies of affinity chromatography resins. A yet known effective approach to increase the dynamic binding capacity of Protein A resins is oligomerization of the particular Protein A motifs. This resembles the tentacle technology used in ion exchange chromatography. Dynamic binding capacities of a hexameric ligand are roughly twice as high compared to capacities obtained with a tetrameric ligand. Further capacity increases up to 130mg/ml can be realized with the hexamer ligand, if the sodium phosphate buffer concentration is increased from 20 to 100mM. Equilibrium isotherms revealed a BET shape for the hexamer ligand at monoclonal antibody liquid phase concentrations higher than 9mg/ml. The apparent multilayer formation may be due to hydrophobic forces. Other quality attributes such as recovery, aggregate content, and overall purity of the captured monoclonal antibody are not affected.
authors.affiliation: Tosoh Bioscience GmbH, Im Leuschnerpark 4, 64347 Griesheim, Germany. Electronic address: Egbert.mueller@tosoh.com.
authors.forename: Egbert
authors.initials: E
authors.lastname: Müller
authors.affiliation: Tosoh Bioscience GmbH, Im Leuschnerpark 4, 64347 Griesheim, Germany. Electronic address: Judith.vajda@tosoh.com.
authors.forename: Judith
authors.initials: J
authors.lastname: Vajda
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000378:metabolism*; D002846:Chromatography, Affinity / Q000295:instrumentation* / Q000379:methods*; D007475:Ion Exchange Resins / Q000737:chemistry*; D013205:Staphylococcal Protein A / Q000737:chemistry / Q000378:metabolism*
chemical_list: D055910:Antibodies, Immobilized; D000911:Antibodies, Monoclonal; D007475:Ion Exchange Resins; D013205:Staphylococcal Protein A
keywords: Dynamic binding capacity; Ligand coupling; Protein A chromatography; Spacer technology; mAb adsorption