Cross-immunogenicity of topological mimics of peptide antigens

Peptide side chain topology plays a central role in peptide antigenicity. Antibody recognition is preserved with peptide mimics resembling the parent peptide's original side chain stereochemical arrangement [1]. Recent work from our group suggested that peptide antigens could be sequence-simplified while maintaining at least part of the antigenic properties of the parent peptide. Synthetic variants of antigenic peptides, one lacking the side chains in the sequence odd position and the other in even position, prepared by replacing amino acid residues in the parent peptide with glycine residues alternately in the sequence, cross-reacted to a significant extent with antibodies raised against the parent peptide [2]. In order to extend our ongoing investigation on the mechanisms responsible for peptide antigenicity, polyclonal antibodies were raised in rabbits against two sequence simplified variants and their ability to recognize the parent antigen was examined by direct and competitive ELISA assays, by plasmon resonance experiments, and by affinity chromatography.