The present invention provides methods for efficiently inducing anti-Aβ antibody and methods for preventing and treating Alzheimers disease. The present inventors successfully induced anti-Aβ antibody in a highly efficient manner by administering an RNA viral vector that expresses a fusion protein between an AB5 toxin B subunit and an Aβ antigen peptide. Administration of the vector resulted in a significant increase of anti-Aβ antibody in plasma, and decrease in the Aβ level in brain tissues and decrease in the anti-Aβ antibody-positive area. The present invention enables more efficient vaccine gene therapy for preventing and treating Alzheimers disease.
