A Bovine Cell Line That Can Be Infected by Natural Sheep Scrapie Prions

Anja M Oelschlegel,Markus Geissen,Marlies Angermann,Roland Riebe,Hermann Schaetzl,Matthias Lenk,Martin H Groschup,Byron Caughey

doi:10.1371/journal.pone.0117154

Abstract

Cell culture systems represent a crucial part in basic prion research; yet, cell lines that are susceptible to prions, especially to field isolated prions that were not adapted to rodents, are very rare. The purpose of this study was to identify and characterize a cell line that was susceptible to ruminant-derived prions and to establish a stable prion infection within it. Based on species and tissue of origin as well as PrP expression rate, we pre-selected a total of 33 cell lines that were then challenged with natural and with mouse propagated BSE or scrapie inocula. Here, we report the successful infection of a non-transgenic bovine cell line, a sub-line of the bovine kidney cell line MDBK, with natural sheep scrapie prions. This cell line retained the scrapie infection for more than 200 passages. Selective cloning resulted in cell populations with increased accumulation of PrPres, although this treatment was not mandatory for retaining the infection. The infection remained stable, even under suboptimal culture conditions. The resulting infectivity of the cells was confirmed by mouse bioassay (Tgbov mice, Tgshp mice). We believe that PES cells used together with other prion permissive cell lines will prove a valuable tool for ongoing efforts to understand and defeat prions and prion diseases.

Highlights

Scrapie is considered to be the archetype of transmissible spongiform encephalopathies (TSE) or prion diseases, a group of fatal neurodegenerative disorders that received considerable public and scientific attention due to a widespread bovine spongiform encephalopathy (BSE) epidemic in cattle in the United Kingdom and elsewhere, and after it was shown that BSE causes a variant form of Creutzfeldt-Jakob disease in humans
We identified, characterized and established a bovine cell line that is susceptible to natural sheep scrapie prions
We have tested a collection of conventional eukaryotic cell lines for their susceptibility to ruminant-derived BSE and scrapie prions

Summary

Introduction

Scrapie is considered to be the archetype of transmissible spongiform encephalopathies (TSE) or prion diseases, a group of fatal neurodegenerative disorders that received considerable public and scientific attention due to a widespread bovine spongiform encephalopathy (BSE) epidemic in cattle in the United Kingdom and elsewhere, and after it was shown that BSE causes a variant form of Creutzfeldt-Jakob disease in humans. Numerous conventional and transgenic rodent models have been established to isolate, quantify and characterize cattle- or small-ruminant-derived BSE and scrapie prions [5, 6]. A major disadvantage of these in-vivo systems is that BSE and scrapie prions, even when adapted to rodents, induce long incubation times of several months or years. These experiments require the sacrifice of numerous animals, and they are cost intensive. For many years it has been a prime objective in prion research to establish prion susceptible cell lines. Cell culture models can facilitate basic as well as diagnostic prion research and last but not least they can be used to screen for potential therapeutic drugs; for ref. see [8]

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