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PMCA to demonstrate the efficacy of prion inactivation methods on reusable medical devices: a relevant alternative to animal bioassays
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Edité par CCSD ; WB Saunders -
International audience. Validation of prion inactivation processes for medical devices relies on in-vivo experimental protocols. However, bioassays are costly, long (1u20132 years) and ethically disputable. Additionally, results obtained with one prion strain u2013 for example, 263K (hamster-adapted strain originating from sheep scrapie) u2013 cannot be easily extrapolated to relevant human prion strains, further questioning the utility of bioassays. Over the past two decades, cell-free prion amplification assays have emerged as potential alternatives to bioassays. Rather than measuring prion infectivity, they quantify prion seeding activity (i.e. the capacity to convert the normal prion protein into the disease-associated isoform). The results obtained from an optimized cell-free assay termed u2018miniaturized-bead protein misfolding cyclic amplificationu2019 (mb-PMCA) with four processes using three different prion strains u2013 263K and two human prions derived from variant and sporadic Creutzfeldtu2013Jakob disease u2013 were compared with published bioassays using the same three strains and processes, when available. Tests performed on reference processes (steam, sodium hydroxide, sodium hypochlorite) and low temperature H2O2 sterilization (STERRAD NXTM Advanced cycle) showed perfect alignment between mb-PMCA and available bioassays. STERRAD NXTM Advanced cycle was efficacious against all three prion strains. These data confirm that PMCA, particularly mb-PMCA, is a relevant alternative to animal bioassays for the assessment of prion inactivation processes, and highlight the interest of some low temperature H2O2 sterilization cycles.