Isolated PHF and PHF-TAU (A68) polypeptides in Alzheimer's disease contain epitopes from the whole sequence of different tau isoforms and modified sites recognized by RT97 and 8D8 anti-neurofilament antibodies: J.P. Brion1, A.M. Couck1, B.H. Anderton2, 1Laborat. of Pathology and Electron Microscopy, Université Libre de Bruxelles, Belgium and 2Depart. of Neuroscience, Institute of Psychiatry, London, UK