Prion-like aggregates: infectious agents in human disease.

According to the 'protein only hypothesis', Creutzfeldt-Jakob disease and other prion disorders are transmissible by misfolded and aggregated prion proteins that act as templates for the misfolding of the same protein in the recipient. The misfolding and aggregation of the prion protein are akin to the genesis of amyloid fibrils formed by several human and animal proteins associated with more common diseases. Two murine forms of amyloidosis, including a model of human AA amyloidosis, are transmissible. Here, we explore the possibility that human prion diseases and more common maladies associated with amyloid deposits might be transmissible by seeding or perhaps even by crossing species barriers.