[Prions and their characteristics in light of recent tests]

Some Prusiner's research leading to prion discovery as well as structure and properties of cellular protein (PrPc) and infectious prion protein (PrPsc) were presented. Unusual resistance of PrPsc to physical and chemical agents was shown. Prusiner's theory on PrPsc creation as an etiological agent of transmissible spongioform encephalopathies (TSE) in humans and animals was described. We also report the controversial to Prusiner's theory, that the nucleic acid or virion must be a component of infectious agent in TSE etiology. More important human prion protein gene mutations connected with development of prion diseases were shown.