The biopharmaceutical industry urgently needs a solution to this dilemma. To meet the demands of these increased titers, protein A chromatography columns need to be further scaled up in size and/or run in multiple cycles - with a consequent increase in buffer consumption, preparation, and storage. Finally when protein A chromatography is used in large-scale operations, the media must be stored in 20% v/v ethanol, which requires fire-proof facility designs.Īntibody expression levels have significantly increased to ≥10 g/L in fed-batch cultures thanks to advances in expression vectors, host cell lines, and media development ( 14). In addition, leached protein A must be removed from final products because the ligand is a potent immunomodulator, and its final levels need to be verified by an ELISA release assay ( 11, 12, 13). Protein A chromatography media are expensive, US$9,000–12,000 per liter. KEYWORDS: BINDING CAPA#CITY, CATION-EXCHANGE CHROMATOGRAPHY, PROTEIN A WHO SHOULD READ: PROCESS DEVELOPMENT PERSONNEL Most commercially available protein A resins can not withstand cleaning at high concentrations of sodium hydroxide except for MAbSelect SuRe brand from GE Healthcare ( which is chemically modified to tolerate extreme pH conditions ( 9, 10). The dynamic binding capacity of protein A chromatography resins is generally ≤40 g/L and depends highly on residence time because of the diffusional nature of the binding process. The resulting specificity provides substantial reduction in impurities such as host cell proteins (HCPs) and DNA ( 4, 5, 6, 7, 8). It yields high purity because only the fragment-crystallizable (Fc) region of an antibody (IgG 1 or IgG 2) or Fc-containing fusion protein can bind to the protein A ligand. Protein A affinity chromatography is traditionally used as the capture step for monoclonal antibodies (MAbs) ( 1, 2, 3).

Capto s impact resin