Scrapie strains maintain biological phenotypes on propagation in a cell line in culture

Bovine spongiform encephalopathy (BSE) and its human equivalent, variant Cr eutzfeldt-Jakob disease (vCJD), are caused by the same strain of infectious agent, which is similar to, but distinct from, > 20 strains of their sheep scrapie homologue, A better understanding of the molecular strain determin ants could be obtained from cells in monoculture than from whole animal stu dies where different cell targeting is commonly a strain-related feature. A lthough a few cell types can be infected with different strains, the phenot ypes of the emergent strains have not been studied. We have cured the scrap ie-infected, clonal SMB cell line with pentosan sulfate, stably re-infected it with a different strain of scrapie and shown that biological properties and prion protein profiles characteristic of each original strain are prop agated faithfully in this single non-neuronal cell type. These findings att est to the fact that scrapie strain determinants are stable and host-indepe ndent in isolated cells.