Quantitation of amyloid-beta peptides in biological milieu using a novel homogeneous time-resolved fluorescence (HTRF) assay.

Many of the recent advances in the understanding of the pathological processes underlying Alzheimer's disease have come about as a result of the development of assays that can specifically quantitate in biological milieu amyloid-beta (A beta) peptides ending at amino-acid positions Ala-42 (A beta(42)) and Val-40 (A beta(40)). The existing technologies, however, although proven in their utility are limited in their application with regards to sample manipulation and suitability for high-throughput screening. To overcome these limitations, in this report we describe the development of a novel homogeneous time-resolved fluorescence (HTRF) immunoassay for A beta(42) and A beta(40) peptides. This assay has the sensitivity, selectivity and dynamic range to allow specific, direct quantitation of A beta peptides in cell culture medium, plasma, cerebrospinal fluid and brain tissue extracts, and has the major advantage of minimising sample manipulation and its inherent inaccuracies.