ELISA method for measurement of amyloid-beta levels

The neuritic plaque in the brain of Alzheimer's disease (AD) patients consists of an amyloid composed primarily of Abeta, an approx 4-kDa peptide derived from the amyloid precursor protein. Multiple lines of evidence suggest that Abeta plays a key role in the pathogenesis of the disease, and potential treatments that target Abeta production and/or Abeta accumulation in the brain as beta-amyloid are being aggressively pursued. Methods to quantitate the Abeta peptide are, therefore, invaluable to most studies aimed at a better understanding of the molecular etiology of the disease and in assessing potential therapeutics. Although other techniques have been used to measure Abeta in the brains of AD patients and beta-amyloid-depositing transgenic mice, the enzyme-linked immunosorbent assay (ELISA) is one of the most commonly used, reliable, and sensitive methods for quantitating the Abeta peptide. Here we describe methods for the recovery of both soluble and deposited Abeta from brain tissue and the subsequent quantitation of the peptide by sandwich ELISA.