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The Seprion Separation System Development of a feasible blood screening protocol for abnormal prion protein Stuart Wils

. Immunohistochemistry Spongiform changes in cerebral cortex with plaques (arrow). Histopathology

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The Seprion Separation System Development of a feasible blood screening protocol for abnormal prion protein Stuart Wils

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    4. Post-mortem tests and the use of protease The large aggregates of rogue prion protein in the brain are relatively resistant to protease allowing the normal prion protein (PrPc) to be digested away prior to testing. But: Problems with standardisation – lab to lab; sample to sample; tissue to tissue leading to false positives Problems with automation No guarantee that all rogue prion is protease resistant Even post-mortem - atypical scrapie (nor98) and BSE Ante-mortem - is rogue prion in blood resistant to protease? Most post-mortem tests cannot easily be applied to ante-mortem testing

    5. Introduction to the Seprion Separation System

    6. Technology background

    8. Western analysis of Seprion-captured material from BSE-infected and uninfected brain no protease used

    9. Western analysis of Seprion-captured material – effect of Proteinase K

    10. The Seprion Separation System works for all TSEs

    15. TSE post-mortem commercial summary The Idexx BSE and CWD commercial assay has 100% specificity and 100% sensitivity compared to existing EU approved tests on brain and lymph nodes USDA approval for BSE and CWD EU approval for BSE and scrapie 100% sensitivity and specificity compared to IHC on ante-mortem scrapie RAMALT testing

    16. The Seprion Separation System

    18. The Seprion Separation System applied to blood screening for TSEs

    19. Keeping blood safe The size of the problem is still unknown Blood related transmission has occurred Reduce risk by exclusion Donor exclusion. Incomplete. Leucodepletion. Animal models demonstrate that 55% of infectivity remains (Rohwer, 2004) Filtration. Pall Corp, PRDT. Animal organ spiking models. Endogenous infection may be species specific. Prion in plasma may be complexed with other proteins/lipid rafts. Quality assurance? Epidemiology? Abrogate risk through blood testing

    20. Protocol for 225 microliters plasma

    21. NIBSC blind panel of vCJD spleen spiked into plasma

    22. Seprion assay results for 236 human plasma donations

    23. Detection of PrPSc in sheep – symptomatic and asymptomatic

    24. Time from Seprion assay positive to clinical signs for four scrapie infected sheep

    25. Results of the Seprion plasma assay on a blind panel of sheep samples provided by the VLA

    26. Scrapie time course – study months 1 and 2

    27. Summary

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