Abnormally phosphorylated protein tau in the cortex of aged individuals ofvarious mammalian orders

Aged individuals of mammalian species displaying hyperphosphorylated tau pr otein may be suitable natural models for investigating neurodegenerative al terations occurring, for example, in Alzheimer's disease. Therefore, autopt ic tissue from the entorhinal, motor and prefrontal cortices of 14 mammalia n species was screened using the monoclonal antibody AT8, which is directed against a phosphorylated epitope of human tau and applicable to the tissue s of aged domestic animals, as shown in previous studies. AT8-immunoreactiv e neuronal processes and perikarya were revealed in Campbell's guenon, rhes us monkey, baboon, rabbit, spectacled bear, guanaco, reindeer and bison. Si gns for considerable neuropathological alterations in aged bisons also incl uded neuropil threads, whereas AT8 immunoreactivity in the other species wa s only sparsely scattered. Hyperphosphorylated tau in the brain of an 28-ye ar-old rhesus monkey was also detected by AT100, PHF-1 and TG-3 antibodies, but only in the hippocampal formation and entorhinal cortex, which are kno wn as starting point for tangle spreading in the cortex of Alzheimer patien ts.