Vet. Res. 37 (2006) 695-703
DOI: 10.1051/vetres:2006024

Degradation of scrapie associated prion protein (PrP^Sc) by the gastrointestinal microbiota of cattle

Christina Scherbel^a, Rohtraud Pichner^a, Martin H. Groschup^b, Simone Mueller-Hellwig^c, Siegfried Scherer^c, Richard Dietrich^d, Erwin Maertlbauer^d and Manfred Gareis<sup>a

a</sup>  Institute for Microbiology and Toxicology, Federal Research Centre for Nutrition and Food, E.-C. Baumann Str. 20, 95326 Kulmbach, Germany
^b  Institute for Novel and Emerging Diseases, Friedrich-Loeffler-Institute, Isle of Riems, Germany
^c  Unit of Microbiology, Central Research Institute for Nutrition and Food, Technical University, Munich, Germany
^d  Institute for Hygiene and Technology of Milk, Veterinary Faculty, Ludwig-Maximilians University, Munich, Germany

(Received 15 November 2005; accepted 23 February 2006; published online 6 July 2006)

Abstract - A food-borne origin of the transmission of bovine spongiform encephalopathy (BSE) to cattle is commonly assumed. However, the fate of infectious prion protein during polygastric digestion remains unclear. It is unknown at present, whether infectious prion proteins, considered to be very stable, are degraded or inactivated by microbial processes in the gastrointestinal tract of cattle. In this study, rumen and colon contents from healthy cattle, taken immediately after slaughter, were used to assess the ability of these microbial consortia to degrade PrP. Therefore, the consortia were incubated with brain homogenates of scrapie (strain 263K) infected hamsters under physiological anaerobic conditions at 37 °C. Within 20 h, PrP was digested both with ruminal and colonic microbiota up to immunochemically undetectable levels. Especially polymyxin resistant (mainly gram-positive) bacteria expressed PrP degrading activity. These data demonstrate the ability of bovine gastrointestinal microbiota to degrade PrP during digestion.

Key words: transmissible spongiform encephalopathy / prion / degradation / microbiota / gastrointestinal tract

Corresponding author: manfred.gareis@bfel-kulmbach.de

© INRA, EDP Sciences 2006