CONCENTRATION AND DISTRIBUTION OF INFECTIVITY AND PRPSC FOLLOWING PARTIAL DENATURATION OF A MOUSE-ADAPTED AND A HAMSTER-ADAPTED SCRAPIE STRAIN

PrPSc is a specific protein marker for slow infectious diseases known as the transmissible subacute spongiform encephalopathies. Although Pr PSc is closely associated with infectivity, it is not known if it is t he infectious agent itself, a component of the agent or merely adventi tiously associated with infectivity. In the present study we demonstra te that the resistance of PrPSc to partial denaturation and of infecti vity to inactivation differs markedly for two scrapie strains. Protein ase K treatment or electrophoretic analysis of partially denatured PrP Sc preparations reveal a dissociation between infectivity and demonstr able PrPSc. Our findings support other evidence that not all PrPSc is required for infectivity. Our studies combined with previous biologica l analyses suggest that PrPSc cannot be the sole component associated with the infectious agent.