A novel approach for Aβ₁₋₄₀ quantification using immuno-PCR.

Several lines of evidence suggest that aggregation of the amyloid β-peptide (Aβ) in the brain is a trigger of Alzheimer's disease (AD). Thus, quantification of Aβ in several different types of samples from brain is fundamental for understanding AD pathogenesis. For analysis of the low levels of Aβ present in microdissected neurons, a more sensitive system than the ELISAs used today would be helpful. Here, we report a novel immuno-PCR (IPCR) system in which the lowest quantitative level of Aβ₁₋₄₀ is 2 attomol/μL. We use the novel IPCR to quantify the intracellular Aβ₁₋₄₀ levels in pyramidal neurons microdissected from human brain. We show that the level of Aβ₁₋₄₀ is around 10 attomol/neuron, and thus, only 3 neurons are needed for analysis.