Virology
Studies of the immune system during infection of sheep with
scrapie and BSE agent
Chianini, F
DEFRA funded project in collaboration with VLA
TSE infections do not appear to stimulate an immune response in the animals they infect. However, alterations in globulin levels during scrapie infection have been detected and accumulation of PrPres and infectivity in lymphoid organs is now recognised to occur. The secondary follicles of lymph nodes and spleen also change their ctructure slightly. These findings suggest that cells of the immune system are intimately involved in the pathogenesis of scrapie in sheep and could provide markers of pre-clinical infectivity.
In this study a group of sheep will be injected subcutaneously with scrapie material. The uptake of scrapie infectivity by lymph nodes draining the site of inoculation will be evaluated by examining morphological, immunohistochemical and cell phenotype changes in efferent lymph and lymph nodes removed at biopsy.
Studies will be made of the events that follow acute challenge and changes that can be detected 18 months after challenge. Initial studies will be made in animals of the susceptible PrP genotype and these will be compared with similar studies of animals of the most resistant genotype.
These studies will provide insights into the mechanism of genetic resistance/ susceptibility to scrapie and provide data that may be exploited in the development of techniques for the early diagnosis of scrapie.