NR ATFA
AU Agrimi,U.; Di Bari,M.A.; Fazzi,P.; Borroni,R.; Vaccari,G.; Frassanito,P.; Simson,S.; Boyle,A.; Baron,T.G.M.; Laude,H.
TI Strain variability in small ruminants prion diseases studied by transmission to the bank vole
QU International Conference - Prion 2005: Between fundamentals and society's needs - 19.10.-21.10.2005, Congress Center Düsseldorf - Oral sessions ORAL-05
PT Konferenz-Vortrag
AB
Despite the existence of different strains in transmissible spongiform encephalopathy (TSE) of small ruminants is well known, the extent of strain variability in the field is unclear and the characteristics of strains circulating has not been extensively investigated. The low susceptibility of the available animal models has been for long time one of the main limitations for this kind of study.
We took advantage of a very susceptible rodent model - the bank vole or Clethryonomis glareolus - for investigating the variability of strains in small ruminants TSE. More than 30 isolates of natural TSE from goats and sheep with different PrP genotypes have been collected from Italy, United Kingdom and France. They have been inoculated intracerebrally into voles, along with two cases of experimental BSE in sheep. A number of transmission characteristics have been studied in voles: survival time (s.t.) upon primary transmission and subsequent passages, transmission barrier (s.t. primary transmission/s.t. subsequent passages), PrPsc molecular characteristics by Western-blot, lesion profile, PET-blot. Before inoculation into voles, the molecular characteristics of PrPsc from all isolates have been investigated.
Different categories of scrapie strains are inferred by their transmission characteristics in voles. They all are distinguishable from sheep BSE. The majority of scrapie isolates caused disease with 150-250 days s.t. upon primary transmission, while sheep BSE transmitted with longer s.t. (~500 d.). Two sheep scrapie isolates with molecular weight (MW) of PrPsc similar to sheep BSE transmitted to voles with long s.t. (500-600 d.) and induced the accumulation of PrPsc with variable MW in individual voles' brains, possibly suggesting the existence of a mixture of strains in the original isolate. These putative strains can be separated and maintained constant by subsequent passages in voles where they demonstrate characteristics different from all other strains.
IN Die Autoren sammelten mehr als 30 Scrapie-Isolate aus Italien, England und Frankreich und 2 Isolate BSE-infizerter Schafe. Jedes Scrapie-Isolat wurde gelelektrophoretisch charakterisiert und Rötelmäusen (Rötel- oder Waldwühlmaus, Clethrionomys glareolus) in die Gehirne injiziert, um in diesen Erregerstamm-Eigenschaften wie Inkubationszeit in der ersten und späteren Passagen, Bandenmuster im Western blot (WB) sowie Schädigungsprofil und PrPsc-Konzentrationen im Hirn zu vergleichen. Die Autoren fanden klar unterschiedliche Scrapie-Stämme, die sich aber alle von den Isolaten der BSE-infizierten Schafe unterschieden. Die meisten Scrapie-Isolate führten bei der primären Übertragung auf Wühlmäuse zu Inkubationszeiten von 150-250 Tagen, während die Schaf-adaptierten BSE-Isolate durch Inkubationszeiten um die 500 Tage auffielen. Zwei Scrapie-Isolate führten ebenfalls zu sehr langen Inkubationszeiten von 500-600 Tagen und bei verschiedenen Wühlmäusen zu unterschiedlichen Bandenmustern im Western blot. Im Verlauf weiterer Passagen erwiesen sich diese Isolate als Gemische mehrerer Scrapie-Stämme, die sich trennen ließen.
AD Umberto Agrimi, Michele Di Bari, Paola Fazzi, Renata Borroni, Gabriele Vaccari, Paolo Frassanito, Shimon Simson, Istituto Superiore di Sanità, Italy; Aileen Boyle, Institute for Animal Health, United Kingdom; Thierry Baron, Agence Française de Sécurité Sanitaire des Aliments, France; Hubert Laude, Institut National De La Recherche Agronomique, France
SP englisch
PO Deutschland