Static and dynamic binding behavior of an IgG2 monoclonal antibody with several new mixed mode affinity adsorbents

• Several new mixed-mode ligand-based adsorbents have been investigated.
• Selectivity for an IgG2 mAb is dependent on subtle changes in ligand structure.
• Adsorption isotherms have been determined and Ka and Qmax values derived.
• Efficient recovery of IgG2 mAbs from crude cell culture harvests achieved.
• Host cell protein clearance found to be influenced by the ligand structure.

The binding behavior of several mixed-mode chromatographic adsorbents, derived from different terpyridine-based ligands immobilized onto Sepharose FF™, has been investigated with a humanized IgG2 monoclonal antibody. Static adsorption isotherms were determined and the derived parameters used to guide the choice of ligand structure and adsorption conditions to achieve favorable IgG2 mAb binding under dynamic loading conditions. The binding and elution behavior of selected adsorbents in packed chromatographic columns were studied with the purified IgG2 mAb and crude cell culture broths containing the same IgG2 mAb. Clearance of host cell proteins was found to be strongly influenced by the structure of the ligand used to generate these mixed mode resins. One ligand candidate in particular, ES-(Cl.S.Cl)terpy, was found to possess selectivity on a par with the traditionally employed Protein A affinity adsorbents for the purification of monoclonal IgG2s with an excellent level of clearance of host cell proteins. Moreover, high binding capacities, e.g. between 34 and 70 mg IgG2 mAb/mL resin, were achieved with these new adsorbents.

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