New ELISAs with high specificity for soluble oligomers of amyloid β-protein detect natural Aβ oligomers in human brain but not CSF

Ting Yang, Soyon Hong, Tiernan O'Malley, Reisa A. Sperling, Dominic M. Walsh, Dennis J. Selkoe

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

Background: Soluble oligomers of amyloid ß-protein (Aß) have been increasingly linked to synaptic dysfunction, tau alteration, and neuritic dystrophy in Alzheimer's disease (AD) and mouse models. There is a great need for assays that quantify Aß oligomers with high specificity and sensitivity. Methods: We designed and validated two oligomer-specific (o-) enzyme-linked immunoassays (ELISAs) using either an Aß aggregate-selective monoclonal for capture and a monoclonal to the free N-terminus for detection, or the latter antibody for both capture and detection. Results: The o-ELISAs specifically quantified pure oligomers of synthetic Aß with sizes from dimers up to much larger assemblies and over a wide dynamic range of concentrations, whereas Aß monomers were undetectable. Natural Aß oligomers of similarly wide size and concentration ranges were measured in extracts of AD and control brains, revealing >1000-fold higher concentrations of Aß oligomers than monomers in the soluble fraction of AD cortex. The assays quantified the age-related rise in oligomers in hAPP transgenic mice. Unexpectedly, none of 90 human cerebrospinal fluid (CSF) samples gave a specific signal in either o-ELISA. Conclusions: These new o-ELISAs with rigorously confirmed specificity can quantify oligomer burden in human and mouse brains for diagnostic and mechanistic studies and for AD biomarker development. However, our data raise the likelihood that the hydrophobicity of Aß oligomers makes them very low in number or absent in aqueous CSF.

Original languageEnglish (US)
Pages (from-to)99-112
Number of pages14
JournalAlzheimer's and Dementia
Volume9
Issue number2
DOIs
StatePublished - Mar 1 2013

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Keywords

  • Alzheimer's disease
  • Amyloid β-peptide
  • Brain extracts
  • Cerebrospinal fluid
  • ELISAs
  • Oligomers

ASJC Scopus subject areas

  • Epidemiology
  • Health Policy
  • Developmental Neuroscience
  • Clinical Neurology
  • Geriatrics and Gerontology
  • Psychiatry and Mental health
  • Cellular and Molecular Neuroscience

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