Conformational epitope antibody

Augstein P, Ziegler B, Schlosser M, et al. Immunohistochemical differentiation of monoclonal GAD antibodies recognizing linear or conformational epitope regions. Pancreas 1997 15 139-146. 

Because conformational epitopes are not easily mimicked with linear peptides, which can elicit nonspecific antibodies, several alternative strategies such as synthetic cyclic peptides have been developed [see e.g., (18)]. A similar conformational restriction was seemingly achieved with a P-amyloid peptide that was anchored to the surface of liposomes via hydrophobic tails introduced at its both N- and C-termini. The reconstituted peptide proved highly immunogenic and elicited antibodies that could significantly prevent amyloid plaque formation in a model system (70). 

This procedure is particularly useful where an antibody recognizes an amino acid sequence or carbohydrate moiety, but may be unsuitable for antibodies that bind to a conformational epitope on the protein. 

Unlike linear B-cell epitopes, conformational epitope prediction models were limited by the need to understand antigen-antibody (Ag-Ab) complex structures before applying these algorithms. As with the linear epitopes, researchers started by seeking structural... 

As many B cell epitopes are described to be conformational (Aalberse, 2000), peptides identified by sequential approaches may render limited information and might exhibit reduced antibody-binding affinity. In a very stringent definition, conformational epitopes are composed of amino acids from different loci in the allergen sequence brought into proximity by the tertiary structure of the protein. Systematic characterization of conformational epitopes is much more difficult compared to linear epitopes, because it requires knowledge of the 3D structure, which is often limited. 

They may sensitize as specific proteins characterized by the occurrence of suitable (linear or conformational) epitopes enabling reactions with receptors of the immunological system cells or antibodies produced by them. 

Fu Y, Shearing LN, Haynes S, Crewther P, Tilley L, Anders RF, Foley M, Isolation from phage display libraries of single chain variable fragment antibodies that recognize conformational epitopes in the malaria vaccine candidate, apical membrane antigen-1, J. Biol. Chem., 272(41) 25678-25684, 1997. 

Actually antibodies are either directed against a continuous aminoacid sequence, the continuous epitopes, or a domain which is located on various sites in the aminoacid chain, discontinuous epitopes, or conformational epitopes. Continuous epitopes have served as affinity ligands for antibody... 

Zwitterionic detergents (0.1-0.4%) in the electrotransfer buffer may restore the antibody-binding capacity of conformational epitopes of antigens denatured by SDS (Mandrell and Zollinger, 1984). 

Fig. 2. Fast-acting acid-triggered bispecific antibody delivery systems. These new acid-triggered bispecific antibody carriers are similar to those shown in Fig. 1. However, the MAb that binds effector is directed against a conformational epitope that is altered by the mildly acidic conditions found in endosomes. Such pH-sensitive effector molecules are typified by diphtheria toxin and certain cell-binding defective mutant CRM forms of that toxin. This bispecific antibody-ligand complex spontaneously dis-...

The mode of interaction of polysialic acid with its antibodies is unusual as it requires usually a minimum of about 8-10 sialyl residues for interaction [55-57], Similarly, efficient cleavage of polysialic acid by a bacteriophage endosialidase requires a minimum chain length of 8 sialyl residues (Fig. 10) [55,58]. A likely explanation is that the interacting molecules are recognizing a conformational epitope of the polysialic acid chain [59],... 

The autoantigen used in a test can be of different quality purified or present in a whole mixture of antigens, native or recombinant, and of human or animal origin. Antibodies tend to recognize conformational epitopes, and therefore the three-... 

---