Aβ42 immunization in Alzheimer's disease generates Aβ N-terminal antibodies

Serum samples from Alzheimer's disease (AD) patients immunized with A beta 42 (AN1792) were analyzed to determine the induced antibody properties including precise amyloid-beta peptide (A beta) epitopes and amyloid plaque-binding characteristics. The predominant response in these patients is independent of whether or not meningoencephalitis developed and is against the free amino terminus of A beta. The immunostaining of amyloid plaques in brain tissue by patient sera is adsorbable by a linear A beta 1-8 peptide, demonstrating that the antibodies are directed predominantly to this epitope and not dependent on A beta conformations or aggregates specific to plaques. Furthermore, the antibodies are not capable of binding amyloid precursor protein and would be predicted to be competent in facilitating clearance of amyloid plaques in AD brains.