title: Hybridization of an Aβ-specific antibody fragment with aminopyrazole-based β-sheet ligands displays striking enhancement of target affinity.
abstract: Determining Aβ levels in body fluids remains a powerful tool in the diagnostics of Alzheimer's disease. This report delineates a new supramolecular strategy which increases the affinity of antibodies towards Aβ to make diagnostic procedures more sensitive. A monoclonal antibody IC16 was generated to an N-terminal epitope of Aβ and the variable regions of the heavy and light chains were cloned as a recombinant protein (scFv). A 6 × histidine tag was fused to the C-terminus of IC16-scFv allowing hybridization with a small organic β-sheet binder via Ni-NTA complexation. On the other hand, a multivalent nitrilotriacetic acid (NTA)-equipped trimeric aminopyrazole (AP) derivative was synthesized based on a cyclam platform; and experimental evidence was obtained for efficient Ni(2+)-mediated complex formation with the histidine-tagged antibody species. In a proof of principle experiment the hybrid molecule showed a strong increase in affinity towards Aβ. Thus, the specific binding power of recombinant antibody fragments to their β-sheet rich targets can be conveniently enhanced by non-covalent hybridization with small organic β-sheet binders.
authors.affiliation: Institute for Organic Chemistry, University of Duisburg-Essen, Universitätsstr. 7, 45117 Essen, Germany. thomas.schrader@uni-due.de.
authors.forename: Marco
authors.initials: M
authors.lastname: Hellmert
authors.forename: Andreas
authors.initials: A
authors.lastname: Müller-Schiffmann
authors.forename: Max Sena
authors.initials: MS
authors.lastname: Peters
authors.forename: Carsten
authors.initials: C
authors.lastname: Korth
authors.forename: Thomas
authors.initials: T
authors.lastname: Schrader
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis*; D016229:Amyloid beta-Peptides / Q000737:chemistry; D002384:Catalysis; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D006801:Humans; D006859:Hydrogen / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007128:Immunoglobulin Fragments / Q000737:chemistry; D007167:Immunotherapy; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009532:Nickel / Q000737:chemistry; D009571:Nitrilotriacetic Acid / Q000737:chemistry; D010446:Peptide Fragments / Q000235:genetics; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011720:Pyrazoles / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D057127:Single-Chain Antibodies / Q000737:chemistry*
chemical_list: D016229:Amyloid beta-Peptides; D000939:Epitopes; D007128:Immunoglobulin Fragments; D008024:Ligands; D010446:Peptide Fragments; D011720:Pyrazoles; D011994:Recombinant Proteins; D057127:Single-Chain Antibodies; D006639:Histidine; D009532:Nickel; D006859:Hydrogen; D009571:Nitrilotriacetic Acid