Engineering of Protein A for improved purification of antibodies and Fc-fused proteins

Abstract In industrial scale downstream processing of antibodies and Fc-fusion proteins, Protein A chromatography is the most commonly used purification method. As the treatments for many severe diseases shift toward biological drugs, in particular antibodies, the need for robust purification methods has increased. Since the 1970s, when Protein A debuted as an affinity ligand, the full protein and its domains have been extensively studied. Even if matrices based on unmodified Protein A historically met the process demands of industrial antibody manufacturing, there is room for improvement. The cleaning in place (CIP) methods required for safe reuse of the matrix in therapeutic protein purification pose a problem since the harsh conditions required can be harmful to the proteinaceous purification ligand. Further, the low pH used for elution can sometimes be detrimental to the target protein. Here, efforts to improve these features as well as capacity improvements for Protein A resins will be discussed.