Reivindicaciones

1. An isolated tau-isoform protein or peptide, or a fragment thereof, comprising at the C-terminus domain amino acid sequence WVGCCPW (SEQ ID NO 1) or amino acid sequence GVGWVG, wherein the C-terminus domain is understood as the 30 amino acids sited at the end of the amino acid chain of the protein or peptide. 2. The isolated protein or peptide of claim 1, wherein said protein or peptide consists of amino acid sequence WVGCCPW (SEQ ID NO 1) or amino acid sequence GVGWVG. 3. The tau-isoform protein or peptide of claim 1, wherein the protein or peptide comprises at the C-terminus domain amino acid sequence KKVKGVGWVGCCPWVYGH (SEQ ID NO 2), wherein preferably the C-terminus domain is understood as the 20 or 18 amino acids sited at the end of the amino acid chain of the protein or peptide. 4. The tau-isoform protein or peptide of claim 1, wherein the protein or peptide consists of amino acid sequence KKVKGVGWVGCCPWVYGH (SEQ ID NO 2). 5. The tau-isoform protein or peptide according to claim 3, wherein the protein or peptide comprises peptide sequence: <img class="EMIRef" id="0e63f4ef-73e1-4ebd-afe5-1c67b7c3af71-ib0005" /> 6. The tau-isoform protein or peptide according to claim 3, wherein the protein or peptide consists of SEQ ID NO 14. 7. The tau-isoform protein or peptide according to claim 2, wherein the tau-isoform comprises peptide sequence: <img class="EMIRef" id="0e63f4ef-73e1-4ebd-afe5-1c67b7c3af71-ib0006" /> 8. The tau-isoform protein or peptide according to claim 7, wherein the tau-isoform consists of SEQ ID NO 15. 9. A composition comprising one or a plurality of tau-isoform protein/s or peptide/s according to any of claims 1 to 8. 10. A composition comprising a polynucleotide encoding at least one tau-isoform protein or peptide according to any of claims 1 to 8. 11. The composition of claim 10, wherein the polynucleotide is disposed within a vector selected for its ability to express the protein or peptide in a mammalian cell, preferably in a human cell. 12. A composition as defined in claim 9 or as defined in claim 10, for use in a method of inhibiting the formation of Ab aggregates or tau aggregates in a subject in need thereof. 13. A composition as defined in claim 9 or as defined in claim 10, for use in a method of inhibiting the development or progression of Ab plaque formation in a subject in need thereof. 14. A composition as defined in claim 9 or as defined in claim 10, for use in a method of inhibiting the development or progression of a tauopathy in a subject in need thereof. 15. A composition as defined in claim 9 or as defined in claim 10, for use in a method of inhibiting the development or progression of Alzheimer's disease in a subject in need thereof. 16. A composition comprising an effective amount of the protein as defined in claim 9 or the polynucleotide as defined in claim 10, for use in a method of treatment of a subject having an amyloid disease characterized by aggregation of Tau protein. 17. A pharmaceutical composition comprising a composition as defined in claim 9 or as defined in claim 10, and a pharmaceutically acceptable carrier including a peptide stabilizing excipient. 18. The pharmaceutical composition of claim 17, wherein the peptide stabilizing excipient comprises a preservative, a tonicity adjusting agent, a detergent, a hydrogel, a viscosity adjusting agent, or a pH adjusting agent. 19. An in vitro use of the protein or peptide of any of claims 1 to 8, as a biomarker for the prognosis of an amyloid disease characterized by aggregation of Tau protein in a human subject. 20. An in vitro use of the protein or peptide of any of claims 1 to 8, as a biomarker for the prognosis of Alzheimer's disease in a human subject.