The state of the prion

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 PrPC, 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.