NR AXMP
AU Fujita,Y.; Matsuura,Y.; Ishikawa,Y.; Somerville,R.A.; Kitamoto,T.; Yokoyama,T.; Mohri,S.
TI Heat Resistance of BSE Infectivity by Dehydration of Materials
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Epidemiology, Risk Assessment and Transmission P04.05
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Transmissible spongiform encephalopathy (TSE) is highly resistant to inactivation by heat. In particular, TSE infected tissue is more difficult to inactivate by autoclaving when it has become dried onto surfaces. To demonstrate the effect of hydration on the inactivation of bovine spongiform encephalopathy (BSE) infected tissue by heating, we measured the surviving infectivity after autoclaving using follicular dendritic cell (FDC) bioassay of the knock-in mice expressing the bovine prion protein gene (Ki-Bov mice).
Three different dehydrated levels of the BSE affected cattle brain tissue were prepared: homogenate, macerate and dry. The homogenate sample contained 5-fold higher water content than the macerate. The dry sample was air dried at 65 ° for 2 hours and contained 0.6-fold of water content compared to the macerate by weight. The samples were subjected to gravity-displacement autoclave at 132 °, 134 °, 136 ° or 138 ° for 20 min and then were prepared as 10% inocula by re-homogenisation and sonication in PBS. At 75 days post intraperitoneal inoculation, spleens of Ki-Bov mice were examined by western blot analysis for the presence of the proteinase K resistant prion protein (PrPsc) and by immunohistochemistry for PrPsc deposition in splenic FDC. No infectivity was detected in homogenate after autoclaving at 132 °, though macerate showed infectivity after autoclaving at 132 ° but not 134 °. Surprisingly, infectivity was detected in the dried samples after autoclaving at 138 °.
Our findings indicate that inactivation of the BSE agent may be ineffective by heating at 138 ° or more if the infective material is in a poorly hydrated state.
AD Y. Fujita, Fukuoka Prefectural Office of Meat Inspection, Japan; Y. Matsuura, Y. Ishikawa, T. Yokoyama, S. Mohri, National Institute of Animal Health, Prion Disease Research Center, Japan; R.A. Somerville, Institute for Animal Health, NPU, UK; T. Kitamoto, Tohoku University Graduate School of Medicine, Department of Prion Research, Japan
SP englisch
PO Schottland