The invention relates to poly-α2,8-sialic acid (PSA) mimetic peptide able to modulate specifically PSA-dependent NCAM functions in vitro and in vivo, characterized in that it presents a sequence consisting of 5 to 30 amino acid residues, preferably 9 to 15, most preferably about 12 amino acid residues, said sequence comprising a B epitope recognized by an anti-poly-α2,8 sialic acid antibody, and to its application for the treatment of neurodegenerative diseases, brain and spine lesions, age-related learning and memory problems, and cancer.
