Neurofibrillary tangles of Alzheimer's disease: an immunohistochemical study.

The reactivity of neurofibrillary tangles (NFT) of Alzheimer's disease with several antisera has been studied by immunocytochemistry. They were heavily labelled by an antiserum prepared against isolated NFT; the latter also remained stainable by Bodian-silver method. Some NFT were labelled on vibratome sections by an antimicrotubular protein but remained able to be counterstained by Congo Red, suggesting this labelling could demonstrate material trapped in NFT. The immunoelectron labelling shows that the abnormal filaments, straight as well as 'twisted', are the only structures recognised by the anti-NFT serum. This labelling was prevented only by pre-incubation with fractions enriched in NFT, confirming the presence of unique antigenic determinants in the latter.