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 a method of treatment of Tauopathy disorder using antibody that specifically binds news Tau species, especially Tau species starting from the methionine residue at position (11), said methionine being N-alpha acetylated (AcMet11-Tau). The invention also relates to an antibody that specifically binds this new tau species. Inventors have discovered that AcMet11-Tau is a pathological Tau species that is involved in Tau pathology development. Inventors have demonstrated the causal link between AcMet11-Tau species and Tau pathology by showing that brain expression of AcMet11-Tau species potentiate Tau pathology development in Thy-Tau Transgenic mice and is involved in pathological process, at least by accelerating Tau pathology.

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.