Non-Alzheimer neurofibrillary tangles show β-amyloid-like immunoreactivity

As well as being a neuropathological hallmark of Alzheimerʼs disease (AD), neurofibrillary tangles (NFT) are present in the brain in a number of other neurodegenerative conditions. β-Amyloid (β/A4) plaque formation is a central event in AD, although recent reports indicate that β/A4, and its precursor protein (βAPP), are also associated with AD NFT. Using an antibody to a βAPP epitope overlapping the β/A4 region, we demonstrate that immuno-reactivity is found in extracellular NFT in Niemann-Pick disease, Hallervorden-Spatz disease, progressive supranu-clear palsy and subacute sclerosing panencephalitis. These NFT were not labelled with a β/A4 antibody which recognizes plaque β/A4 in AD, which supports the proposal that β/A4 can exist in different conformations. Our results also imply a common mechanism of NFT development in different neurodegenerative conditions, including those not normally associated with substantial β/A4 deposition or βAPP involvement.