Location: Animal Disease ResearchTitle: A transfectant RK13 cell line permissive to classical caprine scrapie prion propagation Author
Submitted to: Prion
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2016
Publication Date: 5/23/2016
Citation: Dassanayake, R.P., Zhuang, D., Truscott, T.C., Madsen-Bouterse, S.A., O'Rourke, K.I., Schneider, D.A. 2016. A transfectant RK13 cell line permissive to classical caprine scrapie prion propagation. Prion. 10(2):153-64. Interpretive Summary: Classical scrapie is a fatal prion disease that affects the brain of goats and sheep. Bioassay is a highly sensitive method commonly used to study the infectious nature of prions but which requires inoculation of susceptible animals and is very expensive and time-consuming to complete. As an alternative, several rodent cell line-derived culture systems have been developed which are considerably less expensive, more rapid, and non-animal based. While most are highly permissive to infection with rodent-adapted and culture-adapted scrapie prions, rodent-derived culture systems are poorly permissive to scrapie prions in the brain of naturally infected animals. To address this limitation, we developed a rabbit kidney cell line that expresses a form of the prion protein common to many goats and tested for permissiveness to infection with classical scrapie prions in the brain of naturally infected goats. The results demonstrate permissiveness of this cell culture system to several naturally infected goat brain-derived inocula as well as rodent-adapted scrapie prions. Therefore, this cell line will be useful in the study of classical scrapie prions derived from the brain of goats, a natural host species.
Technical Abstract: Classical scrapie is a form of transmissible spongiform encephalopathies (TSE) affecting domestic goats and sheep and disease is characterized by the accumulation of abnormal conformational isoform (PrP-Sc) of normal cellular prion protein (PrP-C) in the central nervous system and, in most cases, lymphoid tissues. To assess the scrapie infectivity of caprine-origin tissues, bioassays can be utilized using kids, lambs or transgenic mice expressing caprine or ovine PRNP alleles. However, incubation periods of caprine scrapie in bioassay models are fairly long. Although cell lines have been extensively used to study sheep scrapie and other TSE infections, reliable natural or transfectant cell lines are currently unavailable to study caprine scrapie. Rabbit kidney epithelial cell line (RK13) has been widely used to express the exogenous PrP-C of species of interest since such transfectants were permissive to infections from most of the corresponding species. Therefore, the goals of this study were to generate an RK13-based transfectant cell line expressing the caprine wild type PRNP allele (cpRK13) and determine its susceptibility to scrapie infection. The cpRK13 and plasmid control transfectants were incubated with brain homogenates prepared from goats and ovinized transgenic mice (Tg338) infected with classical scrapie. PrP-Sc accumulation in the transfectants was assessed by TSE ELISA, immunoblot and immunohistochemistry assays. The cpRK13 transfectants were permissive to several caprine-derived and also Tg338 mouse-passaged caprine and ovine classical scrapie infections. Therefore, cpRK13 transfectant will be a useful model to assess classical scrapie infectivity in caprine brain tissues.