A ten-residue fragment of an antibody (mini-antibody) directed against lysozyme as ligand in immunoaffinity chromatography

The interaction between an antibody molecule and a protein antigen is an example of "natural" protein modelling. Amino acids of the antigen-binding site consisting of three hypervariable segments (L1, L2, L3) of the light (L) and three (H1, H2, H3) of the heavy (H) chain of an antibody molecule interact with amino acids present in an epitope of a protein. A ten-residue peptide was synthesized with an amino acid sequence analogous to the hypervariable L3 segment of a monoclonal antibody directed against lysozyme. The peptide was immobilized on CH-Sepharose 4B and the affinity adsorbent was used to purify lysozyme added to a detergent extract of insect cells infected with a recombinant baculovirus. This methodology may also be applicable to other antigen-antibody combinations, in immunoaffinity chromatography for selective purification of a protein or in an immunosensor for detection of a protein.