PRESENCE OF AXONAL PAIRED HELICAL FILAMENT-TAU IN ALZHEIMERS-DISEASE - SUBMICROSCOPIC LOCALIZATION

While normal adult tau protein is found typically in axons, paired hel ical filament (PHF) tau has been shown immunohistochemically to be in the somatodendritic compartment in Alzheimer's disease (AD). The small amount of PHF-tau (8-11%) found in white matter with immunochemical m ethods is shown here by immunoelectron microscopy to be located in axo ns. It is localized to straight filament variants of PHFs. The small a mount of PHF-tau in white matter, therefore, appears not to result fro m the contamination of immunochemical preparations but to be an integr al constituent of affected axons in AD. (C) 1994 Wiley-Liss, Inc.