Multiplication of the Scrapie Agent

Abstract

ALTHOUGH the transmission of scrapie by the inoculation of filtrates of tissue from affected animals suggests that the agent multiplies in the cells of the host, there is little published evidence of its propagation in cell cultures, Gustafson and Kanitz¹ reported that cell cultures could be established more readily from scrapie-affected sheep or mice than from normal animals and that material from the twenty-third pass of one such cell line was infective for mice. Only two of seven mice reacted, however, so the titre was apparently low and it was not clear whether there had been actual multiplication of the agent or whether this activity was derived from the original tissue.