Cellular and Scrapie Prion Protein Immunolocalization and In Vitro Amyloid Formation

Abstract

Spongiform encephalopathies in humans and animals include fatal neurodegenerative disorders that can be sporadic, infectious, or inherited (1). Regardless of their origin, spongiform encephalopathies are all transmissible to an appropriate animal species (2), with the exception of fatal familial insomnia (FFI) (3), whose transmission is still unknown. The unique features of the infectious agent that causes spongiform encephalopathies prompted Prusiner (4) to coin the term prion to define a new category of pathogens. In Prusiner’s terminology, the etiologic definition is substituted for the neuropathologic one, and spongiform encephalopathies are called prion diseases. Considerable neuropathologic variability among this group of diseases has been described (5). Some forms are characterized by widespread spongiform changes, while others show mostly prion protein (PrP) amyloid deposition (5). Scrapie, a disease naturally occurring in sheep and goats, is the prototype of prion diseases and has been adapted to various experimental rodent species.