Use this URL to cite or link to this record in EThOS:
Title: Studies on the role of jaagsiekte retrovirus in the aetiology of a contagious lung tumour of sheep
Author: Palmarini, M.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1996
Availability of Full Text:
Full text unavailable from EThOS.
Please contact the current institution’s library for further details.
Sheep pulmonary adenomatosis (SPA) is a naturally occurring contagious lung tumour of sheep which has been associated aetiologically with a chimaeric type B/D retrovirus known as jaagsiekte sheep retrovirus (JSRV). Studies on the aetio-pathogenesis of this disease are extremely valuable in comparative pathology because SPA represents a unique model of a naturally occurring lung cancer. The role of JSRV in the aetio-pathogenesis of SPA is largely unknown. This is due to several factors which have hampered research for a number of years, such as the lack of a cell culture system for the propagation of JSRV and the lack of reagents and techniques to detect JSRV. In addition, the presence in the sheep genome of 15 to 20 copies of JSRV-related endogenous sequences has impeded investigation at the molecular level. By sequencing a fraction of the gag gene of enJSRVs, a ScaI restriction site was found to be a molecular marker for the exogenous form of JSRV. JSRV provirus was detected in tumour genomic DNA of SPA-affected animals but not in non-tumour tissues of the same animals or in unaffected controls. These results demonstrated that JSRV was a horizontally transmitted virus, specifically associated with SPA, and it was not an endogenous retrovirus reactivated as a downstream event of neoplasia. Finally, a highly sensitive exogenous-specific hemi-nested PCR was developed utilising primers in the U3 region of the JSRV LTR, where major differences between endogenous and exogenous sequences were found. Employing this test, it was demonstrated that JSRV established a disseminated infection of the lymphoid tissues of sheep affected by SPA, although the epithelial tumour cells are the main sites of viral replication. This finding could be extremely important in future studies aimed at understanding the interaction of JSRV with the host immune system. In conclusion, the data in this thesis present compelling evidence to specifically associate the exogenous form of JSRV with sheep pulmonary adenomatosis, strengthening the view that this virus has a role in the aetiology of the tumour.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available