Infectivity versus toxicity

摘要

Prions are unique in being transmitted by an altered form of a cellular protein - PrP in mammals - without the need for RNA or DNA1. The disease form converts the normal form into one of its own. Mammalian prion diseases are all fatal, and include Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy in cows, scrapie in sheep and chronic wasting disease in elk and deer. On page 540 of this issue, Sandberg et al.2 provide evidence for two distinct PrP populations: infectious and toxic.