Epsilon Archive for Student Projects

Abstract

Scrapie is an infectious neurologic disease in sheep caused by prions, corresponding to transmissible spongiform encephalopathies (TSEs) in other species. The prion is presumably constituted of PrPSc, the misfolded form of the normal endogenous prion protein, PrPC, which is found in practically all cells in the body. PrPSc can induce a conformational change in PrPC and misfold it as an imprint of itself; this is how prions amplify and spread. The process of conformational change is poorly understood and there might exist intermediate forms between PrPC and PrPSc. Bioassay using mice has traditionally been the golden standard in prion studies but is limited by cost and time. Cell culture studies are now used but often rely on using so called rodent-adapted strains and/or cells overexpressing the prion protein.

In this study we made an attempt to infect FLK-BLV cells (ovine cells persistently infected with bovine leukemia virus) with brain material from a Swedish scrapie case in 1986. We have also developed a sensitive western blot assay that detects prion formation but also conformational changes in the prion protein. Digestion with proteinase K for different periods of time is used to establish conformation. No PrPSc was formed in the inoculated cells but there were indications of increased resistance to proteinase K, perhaps reflecting an intermediate form of the prion protein in the cells. Further studies on this cell system are needed before substantial conclusions can be made.