Large Fraction of Scrapie Virus Resistant to Lipid Solvents

Summary

An association of lipid with the virus of scrapie was examined by quantitating the effects of ether, chloroform and fluorocarbon on infectivity. Treatment of infected brain suspensions with ether reduced infectivity up to 2.2 log₁₀ mouse LD₅₀. Chloroform had less effect than ether on the virus, and only a slight loss resulted from partial purification with fluorocarbon. In addition, substantial infectivity resisted sequential treatments with fluorocarbon and chloroform. The results suggest that scrapie virus was present in both solvent-sensitive and solvent-resistant forms, and that the latter probably did not contain lipid as an essential component. The infectivity of ether- and chloroform-treated preparations was not restored by addition of, or sedimentation with, normal, homologous brain suspensions suggesting that ether-sensitive helper substances were not present in normal mouse brain homogenates.

The author thanks Drs. William Hadlow and Lawrence Sturman for helpful discussion, Mr. Richard Kennedy for technical assistance, and Drs. Wallace Rowe and William Hoyer for suggestions regarding the manuscript.