Synthetic antibody fragment as ligand in immunoaffinity chromatography

The possibility that a fragment of an antibody molecule may interact with a protein antigen was tested by studying the binding properties of a thirteen-residue synthetic peptide with an amino acid sequence similar to part of a hypervariable segment of a monoclonal antibody directed against lysozyme. Affinity adsorbents were prepared with this peptide and with non-related peptides as ligand. Non-specific interactions could be abolished by washing the column with 0.05 M sodium thiocyanate in 20 mM tris-HCl (pH 7.4). Lysozyme was only bound to the antilysozyme adsorbent and could be eluted with 1 M sodium thiocyanate. The results show that immunoaffinity chromatography with synthetic peptide ligands which mimic the antigen-binding site may be a useful tool in the selective purification of proteins.