Evidence for the Multiplication of Scrapie Agent in Cell Culture

Abstract

MANY attempts have been made to grow the causative agent of scrapie in cell culture, but there is no unequivocal evidence of multiplication in vitro. Cultures of cells derived from brains of sheep and mice affected with scrapie and from normal animals have been described by Gustafson and Kanitz¹. They observed that many of the cells, which appeared to be astrocytes, had enlarged or bizarre nuclei or were multinucleated and these abnormalities were more marked in preparations from animals affected with scrapie. Mice, inoculated with undiluted tissue culture fluids from some of their scrapie preparations, either primary or serially passaged cells, developed the disease. The passaged cells had undergone twenty-three transfers; however, it was not clear whether the scrapie activity observed was derived from the original brains or had been caused by the multiplication of agent to low titre.