MRC Prion Unit, Department of Neurodegenerative Disease, Institute of Neurology, Queen Square, London WC1N 3BG, UK. charles.weissmann@prion.ucl.ac.uk
There is little doubt that the main component of the transmissible agent of spongiform encephalopathies - the prion - is a conformational variant of the ubiquitous host protein PrP(C), and that the differing properties of various prion strains are associated with different abnormal conformations of this protein. The precise structure of the prion is not yet known, nor are the mechanisms of infection, conformational conversion and pathogenesis understood.