Prion Infection Dynamics

Propagation of a modified form of the cellular prion protein is thought to be the primary cause of the transmissible spongiform encephalopathies, which include kuru, Creutzfeldt-Jakob disease (CJD), scrapie, and bovine spongiform encephalopathy (BSE). These highly unusual neurological maladies seem to arise spontaneously at extremely low rates. In addition, these diseases can be transmitted directly, in which case the incubation period is remarkably constant. The challenge is to understand these crucial features of prion diseases, without invoking the action of any viral agent. A simple model is developed in which the onset and progression of spongiform encephalopathies are explained by the kinetics of prion aggregate formation. Interestingly, ordered aggregations of proteins such as occurs in prion diseases are also associated with other neurological disorders such as Alzheimer’s disease. Thus, insights developed about prion aggregation may have wide significance.