Human Anti-Aβ IgGs Target Conformational Epitopes on Synthetic Dimer Assemblies and the AD Brain-Derived Peptide
(A) [S26CAβ]2 was isolated by SEC using a HiLoad 16/60 Superdex 75 column equilibrated with 25 mM ammonium acetate, pH 8.5. Arrows indicate elution of linear dextran standards, and D and M are abbreviations for Aβ dimers and monomers, respectively. SDS-PAGE analysis of the low molecular weight SEC peaks confirmed the presence of dimers or monomers. A portion of Aβ in the dimer fraction migrated as an ∼16 kDa assembly that was transiently and artificially induced by the detergent ,  (B) Cibacron blue-isolated IVIg IgGs, (C) anti-Aβ N-terminal mAb, 6E10, binding to plate-immobilized Aβ conformers: [S26CAβ]2; PFs, and WT Aβ monomers. (D) Plate-immobilized Cibacron blue-isolated IVIg IgGs binding to solution-phase Aβ conformers, and (E) Aβ competition curves for solution-phase Aβ conformer inhibition of 100 nM Cibacron blue-isolated IVIg IgGs binding to plate-immobilized [S26CAβ]2. The data symbols in Panels B to E represent antibody binding to Aβ conformers as specified in the legend of Panel B.