Abnormal processing and deposition of amyloid-β peptide (Aβ) in extracellular plaques are thought to be central to the pathogenesis of Alzheimer's disease. Immunization with Aβ reduces the amount of brain amyloid, and now in the 21/28 December Nature, Janus et al. (Nature 2000, 408:979-982) and Morgan et al. (Nature 2000, 408:982-985) report that similar immunization protocols also reduce the learning deficit seen in mouse models of Alzheimer's disease.

Janus et al. immunize at 6, 8, 12, 16 and 20 weeks with Aβ in β-pleated sheet conformation, and test using a Morris water maze at 11, 15, 19 and 23 weeks. The immunized mice perform significantly better than non-immunized littermates at 11 and 23 weeks, when two discrete increases in amyloid burden are detected in non-immunized mice. Immunization reduces the amount of dense-cored Aβ plaques by approximately 50%, suggesting that the elicited antibodies...