Molecular model of prion transmission to humans.

To assess interspecies barriers to transmission of transmissible spongiform encephalopathies (TSEs), we investigated the ability of disease-associated prion proteins (PrP(d)) to initiate conversion of the human normal cellular form of prion protein of the 3 major PRNP polymorphic variants in vitro. Protein misfolding cyclic amplification showed that conformation of PrP(d) partly determines host susceptibility.