title: Structural differences of amyloid-β fibrils revealed by antibodies from phage display.
abstract: BACKGROUND
  Beside neurofibrillary tangles, amyloid plaques are the major histological hallmarks of Alzheimer's disease (AD) being composed of aggregated fibrils of β-amyloid (Aβ). During the underlying fibrillogenic pathway, starting from a surplus of soluble Aβ and leading to mature fibrils, multiple conformations of this peptide appear, including oligomers of various shapes and sizes. To further investigate the fibrillization of β-amyloid and to have tools at hand to monitor the distribution of aggregates in the brain or even act as disease modulators, it is essential to develop highly sensitive antibodies that can discriminate between diverse aggregates of Aβ.
  
  
  RESULTS
  Here we report the generation and characterization of a variety of amyloid-β specific human and human-like antibodies. Distinct fractions of monomers and oligomers of various sizes were separated by size exclusion chromatography (SEC) from Aβ42 peptides. These antigens were used for the generation of two Aβ42 specific immune scFv phage display libraries from macaque (Macaca fascicularis). Screening of these libraries as well as two naïve human phage display libraries resulted in multiple unique binders specific for amyloid-β. Three of the obtained antibodies target the N-terminal part of Aβ42 although with varying epitopes, while another scFv binds to the α-helical central region of the peptide. The affinities of the antibodies to various Aβ42 aggregates as well as their ability to interfere with fibril formation and disaggregation of preformed fibrils were determined. Most significantly, one of the scFv is fibril-specific and can discriminate between two different fibril forms resulting from variations in the acidity of the milieu during fibrillogenesis.
  
  
  CONCLUSIONS
  We demonstrated that the approach of animal immunization and subsequent phage display based antibody selection is applicable to generate highly specific anti β-amyloid scFvs that are capable of accurately discriminating between minute conformational differences.
authors.affiliation: Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics, Spielmannstr.7, 38106, Braunschweig, Germany. Patrick.droste@celerion.com.|Current address: Celerion Switzerland AG, Allmendstrasse 32, 8320, Fehraltorf, Switzerland. Patrick.droste@celerion.com.
authors.forename: Patrick
authors.initials: P
authors.lastname: Droste
authors.affiliation: Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics, Spielmannstr.7, 38106, Braunschweig, Germany. andre.frenzel@tu-bs.de.|YUMAB GmbH, Rebenring 33, 38106, Braunschweig, Germany. andre.frenzel@tu-bs.de.
authors.forename: André
authors.initials: A
authors.lastname: Frenzel
authors.affiliation: Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics, Spielmannstr.7, 38106, Braunschweig, Germany. Miriam.steinwand@delenex.com.|Current address: Delenex Therapeutics AG, Wagistrasse 27, 8952, Schlieren, Switzerland. Miriam.steinwand@delenex.com.
authors.forename: Miriam
authors.initials: M
authors.lastname: Steinwand
authors.affiliation: Institut de recherche Biomédicale des Armées (IRBA-CRSSA); Département de Microbiologie; Unité de biotechnologie des anticorps et des toxines, La Tronche Cedex, France. thibaut.pelat@biotem.fr.|Current address: BIOTEM Parc d'Activités Bièvre Dauphine, 885, rue Alphonse Gourju, 38140, Apprieu, France. thibaut.pelat@biotem.fr.
authors.forename: Thibaut
authors.initials: T
authors.lastname: Pelat
authors.affiliation: Institut de recherche Biomédicale des Armées (IRBA-CRSSA); Département de Microbiologie; Unité de biotechnologie des anticorps et des toxines, La Tronche Cedex, France. pthullier@yahoo.com.
authors.forename: Philippe
authors.initials: P
authors.lastname: Thullier
authors.affiliation: Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics, Spielmannstr.7, 38106, Braunschweig, Germany. m.hust@tu-bs.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Hust
authors.affiliation: SV-BMI, Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne, Station 19, 1015, Lausanne, Switzerland. hilal.lashuel@epfl.ch.
authors.forename: Hilal
authors.initials: H
authors.lastname: Lashuel
authors.affiliation: Technische Universität Braunschweig, Institute of Biochemistry, Biotechnology and Bioinformatics, Spielmannstr.7, 38106, Braunschweig, Germany. s.duebel@tu-bs.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Dübel
mesh_terms: D000544:Alzheimer Disease / Q000276:immunology* / Q000473:pathology; D000595:Amino Acid Sequence / Q000235:genetics; D000682:Amyloid / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000276:immunology*; D000906:Antibodies / Q000276:immunology; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D066263:Protein Aggregation, Pathological / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D000682:Amyloid; D016229:Amyloid beta-Peptides; D000906:Antibodies; D000939:Epitopes; D010446:Peptide Fragments