Integration of cell harvest with affinity-enhanced purification of monoclonal antibodies using aqueous two-phase systems with a dual tag ligand

Monoclonal antibodies (mAbs) are currently the most important class of recombinant protein therapeutics in the biotechnological and biopharmaceutical industry with more than 250 therapeutic mAbs currently undergoing clinical trials. High titer producing cultures and complex mixtures containing high cell densities, together with an increasing growing demand for highly pure mAbs is making recovery and purification processes hot targets for improvement and opens important technological challenges in mAbs manufacturing platforms. This work explores the use of an affinity dual ligand based on a choline binding polypeptide tag (C-LytA) fused to the synthetic antibody binding Z domain (LYTAG-Z) in aqueous two-phase systems (ATPS) composed of phase forming polymers able to bind to the choline binding site of C-LytA (polyethylene glycol -PEG- and thermosensitive polymers -EOPO) for mAbs selective extraction. Integration of harvesting and ATPS affinity extraction steps were evaluated with ATPS proving to be an alternative strategy for integrating the clarification and the primary recovery of mAbs. An extraction yield of 89% and a clarification higher than 95% were achieved using a system composed of 7% PEG 3350 and 6% dextran 500,000.