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Assessing Transmissible Spongiform Encephalopathy Species Barriers with an In Vitro Prion Protein Conversion Assay
Published on: March 10, 2015
Decontamination of prion protein (BSE301V) using a genetically engineered protease
J Dickinson1, H Murdoch, M J Dennis
1Health Protection Agency, Porton Down, Salisbury, UK.
Abstract:
A previous study has demonstrated the potential of alkaline proteases to inactivate bovine spongiform encephalopathy (BSE301V). Here we explored the use of MC3, a genetically engineered variant of Bacillus lentus subtilisin. MC3 was used to digest BSE301V infectious mouse brain homogenate (iMBH). MC3 eliminated all detectable 6H4-immunoreactive material at pH 10 and 12; however, Proteinase K was only partially effective at pH 12. When bioassayed in VM mice, MC3- and Proteinase K-digested iMBH gave respectively 66.6% and 22.7% survival rates. Using a titration series for disease incubation, this equates to a >7log reduction in infectivity for MC3 and >6log reduction for Proteinase K. This study demonstrates the potential for thermostable proteases to be developed as effective inactivation processes for prion agents in healthcare management.
Insights
Genetically engineered MC3 protease effectively inactivated infectious prion agents, significantly reducing infectivity in mouse brain homogenate. This protease shows promise for developing new prion inactivation methods in healthcare.
Area of Science:
- Biochemistry
- Prion Biology
- Enzyme Engineering
Background:
- Alkaline proteases show potential for inactivating bovine spongiform encephalopathy (BSE).
- Further research is needed to explore engineered proteases for prion inactivation.
Purpose of the Study:
- To investigate the efficacy of MC3, an engineered Bacillus lentus subtilisin variant, in digesting and inactivating prion infectious mouse brain homogenate (iMBH).
- To compare the prion inactivation capabilities of MC3 with Proteinase K.
Main Methods:
- MC3 and Proteinase K were used to digest iMBH at varying pH levels.
- The degradation of prion protein was assessed using 6H4-immunoreactivity.
- Infectivity was bioassayed in VM mice to determine survival rates and log reduction values.
Main Results:
- MC3 completely eliminated detectable prion protein at pH 10 and 12, while Proteinase K was only partially effective at pH 12.
- MC3 digestion resulted in a >7log reduction in infectivity, compared to a >6log reduction for Proteinase K.
- VM mice challenged with MC3-digested iMBH showed a 66.6% survival rate, versus 22.7% for Proteinase K-digested iMBH.
Conclusions:
- Thermostable proteases, such as MC3, are effective in inactivating prion agents.
- Engineered proteases offer a promising avenue for developing robust prion inactivation strategies in healthcare settings.
- This study highlights the potential of enzyme-based decontamination for managing prion diseases.
