A method for in vivo down-regulation of amyloid protein in an animal, including a human being, the method comprising effecting presentation to the animal's immune system of an immunogenically effective amount of at least one amyloidogenic polypeptide or subsequence thereof which has been formulated so that immunization of the animal with the amyloidgenic polypeptide or subsequence thereof induces production of antibodies against the amyloidogenic polypeptide, and/or at least one analogue of the amyloidogenic polypeptide wherein is introduced at least one modification in the amino acid sequence of the amyloidogenic polypeptide which has as a result the immunization of the animal with the analogue induces production of antibodies against the amyloidogenic polypeptide.