Fig. 3
Increasing PrPSc concentration or sonicating prions increases neuroinvasion of fibrillar prion (strain 87V). a Survival curves of mice inoculated with a 10-fold higher concentration of fibrillar 87V prions (high dose: solid red line) (10% IT: n = 13; 1% IT: n = 9; 1% IC: n = 5) (1% IC and 1% IT mice are the same shown in Fig. 1c). b Representative western blot of brain shows proteinase-K (PK) resistant PrPSc in 3 of 5 mice exposed IT to high dose 87V prions. c Representative images of recombinant PrP fibril ultrastructure show that sonication results in short homogenous fibrils (mean length of unsonicated = 524 nm versus sonicated = 222 nm; P < 0.0001, Student’s t test). d Solubility assay on sonicated and unsonicated fibrils shows that sonication increases the solubility of the fibrils. e Disaggregation assay. Western blots show the increase of PK-resistant 22L and 87V prions in the supernatant following sonication of prion-infected brain homogenate. Quantification shows the results of all strains. f Survival curve of mice inoculated with sonicated, low dose (1%) fibrillar 87V prions. n = 10 (1% sonic. IT), 9 (1% IT), 4 (1% sonic. IC). The 9 mice inoculated with 1% prions IT are also shown in panel a and Fig. 1c. g Representative western blot of brain from mice exposed IT to sonicated fibrillar 87V prions shows PK-resistant PrPSc in 3 of 5 mice. h PrPSc shows large dense plaques in the brains of mice (cerebral cortex) exposed IC or IT to sonicated 87V prions. “n”: mock-inoculated brain control. Scale bars = 500 nm (c) and 100 μm (h)