Exposure of RML scrapie agent to a sodium percarbonate-based product and sodium dodecyl sulfate renders PrP(Sc) protease sensitive but does not eliminate infectivity

BACKGROUND: Prions, the causative agents of the transmissible spongiform encephalopathies, are notoriously difficult to inactivate. Current decontamination recommendations by the World Health Organization include prolonged exposure to 1 N sodium hydroxide or > 20,000 ppm sodium hypochlorite, or autoclaving. For decontamination of large stainless steel surfaces and equipment as in abattoirs, for example, these methods are harsh or unsuitable. The current study was designed to evaluate the effectiveness of a commercial product containing sodium percarbonate to inactivate prions. Samples of mouse brain infected with a mouse-adapted strain of the scrapie agent (RML) were exposed to a sodium percarbonate-based product (SPC-P). Treated samples were evaluated for abnormal prion protein (PrP(Sc))-immunoreactivity by western blot analysis, and residual infectivity by mouse bioassay. RESULTS: Exposure to a 21% solution of SPC-P or a solution containing either 2.1% or 21% SPC-P in combination with sodium dodecyl sulfate (SDS) resulted in increased proteinase K sensitivity of PrP(Sc). Limited reductions in infectivity were observed depending on treatment condition. A marginal effect on infectivity was observed with SPC-P alone, but an approximate 2–3 log(10) reduction was observed with the addition of SDS, though exposure to SDS alone resulted in an approximate 2 log(10) reduction. CONCLUSIONS: This study demonstrates that exposure of a mouse-adapted scrapie strain to SPC-P does not eliminate infectivity, but does render PrP(Sc) protease sensitive.