Use of antibodies is rapidly increasing in therapy and diagnosis and technology relevant to antibody production and purification is of great academic and industrial interest. Although bacterial protein A and protein G have been widely used as affinity ligands for antibody purification, use of these proteins has many disadvantages leaving much room for the development of small ligands. We have previously described an IgG Fc domain-binding cyclic peptide conjugate (FcBP) consisting of 13 amino acids and a soluble surface linker, which was used for the efficient capture of antibodies on a surface plasmon resonance (SPR) chip. In the present study, the peptide was immobilized on Sepharose resin and packed into columns, and the use of such columns for antibody purification was investigated.
All four columns packed with FcBP, reduced FcBP (FcBP-Red), protein A, or protein G showed good binding capacities for a human IgG, Herceptin. Of these columns, FcBP-Red allowed antibody purification at a less acidic pH (pH 2.8) than was required by the protein affinity columns (pH 2.1 and 2.3 for protein G and protein A columns, respectively). The use of FcBP column also purified antibody of swine serum to a level as pure as that obtained from the protein columns, and the regenerated FcBP column operated 30 runs without loss of efficiency, which is the maximum number performed in the present study. These results demonstrate that FcBP, used as a robust affinity ligand for antibody purification, is a viable alternative compensating the disadvantages associated with protein affinity ligands such as protein G and protein A.