Attempts to release the scrapie agent from tissue debris

Experiments are described in which the action of fluorocarbon, detergents, solvents and salt solutions on scrapie-containing preparations was investigated. In no case was any useful extraction of the scrapie agent from tissue debris achieved, although the methods used here included some that have been applied successfully for the isolation of small DNA viruses. The results obtained suggest either that the scrapie agent is unstable except when bound to tissue debris or that it requires the presence of other brain components for the expression of its full activity. It may not be closely related in its structure to any of the known viruses. The scrapie agent is insensitive to the action of many enzymes, but its activity may in certain circumstances be reduced in the presence of trypsin.