Abstract: The invention relates to the identification of a new Tau species starting at residue Met11 (Met11-Tau) which is N-alpha-terminally acetylated form (N-alpha-acetyl-Met11-Tau species: Ac-Met11-Tau). Several monoclonal antibodies specific of this new Tau species have been developed. One of this antibody, 2H2/D11, was used in THY-Tau22 mouse model (that develops with age neurofibrillary degeneration (NFD) and memory deficits), and N-alpha-Ac-Met11-Tau species were clearly detected early in neurons displaying NFD on hippocampal brain sections while it is not reactive in hippocampus from elderly controls. Finally, by using ELISA sandwich specific of Ac-Met11-Tau species, Alzheimer Disease (AD) brain samples are clearly discriminated from human elderly control brains. Thus the invention relates to this new Tau species starting from the methionine residue at position 11 said methionine being N-alpha acetylated.

Abstract: The invention relates to the identification of a new Tau species starting at residue Met11 (Met11-Tau) which is N-alpha-terminally acetylated form (N-alpha-acetyl-Met11-Tau species: Ac-Met11-Tau). Several monoclonal antibodies specific of this new Tau species have been developed. One of this antibody, 2H2/D11, was used in THY-Tau22 mouse model (that develops with age neurofibrillary degeneration (NFD) and memory deficits), and N-alpha-Ac-Met11-Tau species were clearly detected early in neurons displaying NFD on hippocampal brain sections while it is not reactive in hippocampus from elderly controls. Finally, by using ELISA sandwich specific of Ac-Met11-Tau species, Alzheimer Disease (AD) brain samples are clearly discriminated from human elderly control brains. Thus the invention relates to this new Tau species starting from the methionine residue at position 11 said methionine being N-alpha acetylated.