Biological infectivity assay of in vitro-generated autocatalytic PrPSc molecules.

RML prions were propagated in vitro by sPMCA with purified CHO-expressed PrPC+Prnp0/0 brain homogenate.aGenerated by in vitro propagation of ΔC-PBD PrPSc (Figure 2).bPropagation in mock-purified untransfected CHO lysate+Prnp0/0 brain homogenate.cUnseeded PMCA reactions.dUpon observation of clinical signs, scrapie illness was confirmed by Western blot for protease-resistant PrP and histopathology for spongiform degeneration.eThese animals showed no clinical signs of scrapie illness, and upon death or sacrifice were found to be negative biochemically for protease-resistant PrP and pathologically for spongiform degeneration. After >600 days post-inoculation, all remaining animals were sacrificed, analyzed for PrPSc, and included in this table.fThese animals showed no clinical signs of scrapie illness, but tissue was not obtained due to sacrifice for other condition (such as dermatitis) or sudden death.