Authors : Michelle M. Dennis , Joni Triantis , Salman and Daniel H. Gould
Abstract: Prions are exceptionally resistant to physical or chemical methods of degradation. Conditions that result in prion destruction under natural conditions or that may be used for environmental decontamination or disposal of biowastes need to be elucidated. It was hypothesized that long-term heating may be effective at destroying prions. The immunodetection of protease-resistant, disease-associated Prion Protein (PrPres) is an expedient approach to screen physiochemical conditions for potential to destroy prions. The present objective was to characterize PrPres immunodetectability in brain from Chronic Wasting Disease (CWD)-affected elk that was subjected to heat over time. Three commercially available diagnostic assays for CWD demonstrated progressive loss of PrPres immunodetectability when brain homogenates were incubated at 37, 55 and 80�C for 200 days. The rate of PrPres immunoreactivity reduction increased with incubation temperature and was comparatively more substantial when brain homogenates were incubated as 20% solutions in sterile water. When samples were incubated at 55 or 80�C, PrPres immunoreactivity eventually declined below the detection limits of all three assays. Results indicate the potential for environments and biodisposal systems that maintain high temperatures over time to naturally degrade prions. Ultimately, bioassay is necessary to determine whether infectivity is absent from treated samples with depleted, detectable PrPres. Furthermore, findings suggest that PrPres immunoassays may not be accurate when applied to brain samples that were weakly positive and have had long post-mortem or post-collection intervals, or have been exposed to high temperatures.
Michelle M. Dennis , Joni Triantis , Salman and Daniel H. Gould , 2007. Heat-Dependent Loss of PrPres Immunoreactivity Using Three Detection Systems . Veterinary Research, 1: 76-83.