Fundamentals of prions and their inactivation (review).

Prion is an infectious particle composed of an abnormal isoform of the prion protein (PrPSc) and causes prion diseases such as bovine spongiform encephalopathy (BSE), Creutzfeldt-Jakob disease (CJD) and scrapie. Host cells express cellular prion protein (PrPC), which plays roles in normal functions such as anti-oxidative stress. PrPSc is derived from PrPC and produced by conformational conversion. Prion is notorious as a resistant pathogen, being difficult to inactivate with conventional sterilization procedures. Therefore, to prevent prion-caused iatrogenic diseases, the use of appropriate procedures to inactivate prions is important. For examples, alcohol treatment, autoclave (121˚C, 20 min) and γ-ray irradiation, which are used for disinfection, antisepsis or sterilization of viruses and bacteria, are not effective against prion. This is a fundamental review of prions and methods of their inactivation.