Infectivity-associated PrP Sc and disease duration-associated PrP Sc of mouse BSE prions

However, the specific role of PrP Sc in prion pathogenesis and its relationship to infectivity remain controversial. A time-course study of prion-affected mice was conducted, which showed that the prion infectivity was not simply proportional to the amount of PrP Sc in the brain.

Centrifugation (20,000 × g ) of the brain homogenate showed that most of the PrP Sc was precipitated into the pellet, and the supernatant contained only a slight amount of PrP Sc . Interestingly, mice inoculated with the obtained supernatant showed incubation periods that were approximately 15 d longer than those of mice inoculated with the crude homogenate even though both inocula contained almost the same infectivity.