Persistent Amyloidosis following Suppression of Aβ Production in a Transgenic Model of Alzheimer Disease Persistent Amyloid in Tet-Off APP Mice Abstract Background The proteases (secretases) that cleave amyloid-β (Aβ) peptide from the amyloid precursor protein (APP) have been the focus of considerable investigation in the development of treatments for Alzheimer disease. The prediction has been that reducing Aβ production in the brain, even after the onset of clinical symptoms and the development of associated pathology