Oxidized forms of the peptide beta-amyloid (Aβ) are considered to be toxic to the brain, leading to the development of Alzheimer's disease (AD). Based on our preliminary data, we hypothesize that an immunization of an AD-model mice with a recombinant protein enriched with the oxidized amino acid methionine sulfoxide will cause the removal of toxic Aβ from brain. Consequently, this treatment is expected to inhibit the development of AD and alleviate cognitive impairment.