(263e) Performance of Hexamer Peptide Ligands for Affinity Purification of IgG From Cell Culture and Other Media

Hexapeptide ligands HWRGWV, HYFKFD, and HFRRHL for IgG purification have been identified by a three-step screening procedure of a combinatorial solid phase library. These peptide ligands have the unique ability to bind specifically to the Fc region of IgG. This work addresses important issues related to successful application of these ligands to the industrial scale purification of IgG. First, the influence of sodium chloride and sodium caprylate are investigated to obtain high IgG yield and purity. Secondly, an efficient regenerating agent has been identified in order to increase column reusability. With these protocols we demonstrate the applicability of the hexapeptide ligands for the purification of commercial humanized and chimeric monoclonal antibodies from CHO cell culture supernatants and polyclonal IgG from milk, whey and human plasma. The purities and yields obtained for the IgG purification from all these sources were found higher than 90% and 80% respectively. Dynamic binding experiments were also performed with CHO cell culture supernatant and pure human polyclonal IgG. The dynamic binding capacity of the peptide resins for a humanized monoclonal antibody and pure IgG was around 20 mg/ml and 25 mg/ml respectively.