This is an N-terminal fragment of beta amyloid. It consists of amino acid residues 1 to 9. Truncated beta amyloid peptide (10-40) still forms amyloid fibrils and shows fibril polymorphism. The fact that this peptide fragment (1-9) contains a functional B cell epitope but lacks known T cell epitopes makes it a desirable candidate for the development of beta-amyloid vaccines with a low risk of autoimmune encephalitis.