Antibody combining site, mimicry

Nevertheless, the potential for autoimmune disease would clearly exist if one considers the polyspecificity of immune recognition molecules such as B cell receptors, antibodies, T cell receptors and MHC molecules. Further, the polyspecificity of immune receptors is also able to transcend the biochemically defined classes of biomolecules. For instance, the monoclonal antibody SYA/J6 has been demonstrated to have a dual specificity, binding a specific carbohydrate or a specific peptide with comparable affinity.68 Detailed analysis of the interatomic interactions between the antibody combining site and either the carbohydrate or the peptide antigens demonstrated that functional mimicry is possible without exact structural mimicry. This example underlines the case that it is not possible to predict with certainty whether the molecular surfaces of all potentially cross-reactive epitopes, whether of foreign or self molecules, will, or will not, be able to bind to a specific antibody. 

Vyas NK, Vyas MN, Chervenak MC, Bundle DR, Pinto BM, Quiocho FA. Structural basis of peptide-carbohydrate mimicry in an antibody-combining site. Proc Natl Acad Sci USA. 2003 100(25) 15023-15028. 

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