Structure-based design of conformation- and sequence-specific antibodies against amyloid β

Conformation-specific antibodies that recognize aggregated proteins associated with several conformational disorders (e. g., Parkinson and prion diseases) are invaluable for diagnostic and therapeutic applications. However, no systematic strategy exists for generating conformation-specific antibodies that target linear sequence epitopes within misfolded proteins. Here we report a strategy for designing conformation-and sequence-specific antibodies against misfolded proteins that is inspired by the molecular interactions governing protein aggregation. We find that grafting small amyloidogenic peptides (6-10 residues) from the A beta 42 peptide associated with Alzheimer's disease into the complementarity determining regions of a domain (V-H) antibody generates antibody variants that recognize A beta soluble oligomers and amyloid fibrils with nanomolar affinity. We refer to these antibodies as gammabodies for grafted amyloid-motif antibodies. Gammabodies displaying the central amyloidogenic A beta motif ((18)VFFA(21)) are reactive with A beta fibrils, whereas those displaying the amyloidogenic C terminus ((34)LMVGGVVIA(42)) are reactive with A beta fibrils and oligomers (and weakly reactive with A beta monomers). Importantly, we find that the grafted motifs target the corresponding peptide segments within misfolded A beta conformers. A beta gammabodies fail to cross-react with other amyloidogenic proteins and scrambling their grafted sequences eliminates antibody reactivity. Finally, gammabodies that recognize A beta soluble oligomers and fibrils also neutralize the toxicity of each A beta conformer. We expect that our antibody design strategy is not limited to A beta and can be used to readily generate gammabodies against other toxic misfolded proteins.