The
transmissible spongiform encephalopathies (TSEs) or
prion diseases are infectious
neurodegenerative diseases of mammals.
Protease-resistant
prion protein (
PrP-res) is only associated with TSEs and thus has been a target for therapeutic intervention. The most effective compounds known against
scrapie in vivo are inhibitors of
PrP-res in infected cells. Mouse
neuroblastoma (N2a) cells have been chronically infected with several strains of mouse
scrapie including RML and 22L. Also, rabbit epithelial cells that produce sheep
prion protein in the presence of
doxycycline (Rov9) have been infected with sheep
scrapie. Here a high-throughput 96-well plate
PrP-res inhibition assay is described for each of these
scrapie-infected cell lines. With this dot-blot assay, thousands of compounds can easily be screened for inhibition of
PrP-res formation. This assay is designed to find new
PrP-res inhibitors, which may make good candidates for in vivo anti-
scrapie testing. However, an in vitro assay can only suggest that a given compound might have in vivo anti-
scrapie activity, which is typically measured as increased survival times. Methods for in vivo testing of compounds for anti-
scrapie activity in transgenic mice, a much more lengthy and expensive process, are also discussed.