Like a prion, Alzheimer's protein seeds itself in the brain

The Alzheimer’s-related protein amyloid-beta is an infectious instigator in the brain, gradually contorting its harmless brethren into dangerous versions, new evidence suggests. The study adds to the argument that A-beta is a prion, a misfolded protein that behaves like the contagious culprits behind Creutzfeldt-Jakob disease in people, scrapie in sheep and mad cow disease.