PRION PROTEIN AND THE SCRAPIE AGENT - IN-VITRO STUDIES IN INFECTED NEUROBLASTOMA-CELLS

The mouse neuroblastoma cell line N2a was persistently infected with t he Chandler strain of the mouse scrapie agent. Although the infection did not spread to infect > 1% of the cells, clones were established th at had from 50 to 100% infected cells. These clones expressed the abno rmal protease-resistant form of prion protein (PrP), which is believed to mediate brain degeneration in animals with scrapie and bovine spon giform encephalopathy and in humans with kuru, Creutzfeldt-Jakob disea se, and Gerstmann-Straussler-Scheinker syndrome. With this in vitro sy stem, Congo red and several sulfated polysaccharides, including hepari n and pentosan polysulfate, were found to inhibit accumulation of prot ease-resistant PrP. These results and additional data confirming PrP b inding to heparin suggested a possible role for sulfated glycosaminogl ycans in the generation of protease-resistant PrP during scrapie infec tion. Accumulation of protease-resistant PrP was also blocked in vitro by expression of foreign PrP molecules, indicating that PrP from diff erent species might compete for common substrates in this process. The se results using scrapie infected cell lines provide new opportunities for development of drugs capable of blocking the brain degeneration c aused by scrapie and other transmissible spongiform encephalopathies.