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Title: Identification and characterization of transformed cells in jaagsiekte, a contagious lung tumour of sheep
Author: Jassim, Fadhil Abbas
ISNI:       0000 0001 3589 4196
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1988
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Jaagsiekte is a contagious lung tumour of sheep in which two types of secretory epithelial cell in the lower respiratory tract are transformed. These cells are type II pneumocytes in the alveoli, and the cells of Clara in the terminal bronchioles. An efficient and reproducible technique is described for the isolation of transformed SPA cells. It includes three basic steps: Prolonged trypsinisation to kill fibroblasts, magnetic removal of macrophages, and adherence to remove the rapidly adherent cells. The resultant preparations of lung cells were enriched to 96.6% type II pneumocytes. Four cell lines were initiated from lungs of sheep with pulmonary adenomatosis and two of the cell lines have been continuously propagated in vitro for more than 140 passages. The morphologic and cytogenetic characteristics of these lines have been examined. The cells are epithelial and demonstrate ultrastructural features consistent with the tumour of origin. The lines are aneuploid and contain a spectrum of cytogenetic marker chromosomes SPARV P25 was detected in all cell lines in early passes, but was undetectable after 11th passage. After 16 or 20 in vitro passages, three cell lines grew in soft agar with low cloning efficiency. However, the efficiency increased with higher passage numbers. The effect of bromhexine HC1 and prednisolone on the morphology and ultrastructure of SPA cell lines ( JS7 and JS8 ) was studied. Cells treated with prednisolone lost their squamous epithelial shape and assumed a fusiform swirling appearance. Coincident with this change in morphology, the JS7 cells also lost the characteristic cytoplasmic lamellar bodies but not apical microvilli nor desmosomes. Cells treated with bromhexine HC1 showed an increase in the number and size of lamellar bodies, and retained their squamous epithelial appearance. When the cell lines were transplanted subcutaneously in athymic nude mice, they induced palpable fluid-filled, cyst-like tumours at the site of injection. Tumour cells had a morphology similar to that of the parent cells and the original adenomatosis lung tumour cells of jaagsiekte, even though they had been through many in vitro passages. Ultrastructural and cytogenetic analysis of cell cultures derived from the nude mice tumours showed these to possess only the sheep karyotype. SPA was successfully reproduced in neonatal lambs by intratracheal inoculation of passaged cells. Macroscopic lesions of SPA were observed in lambs and confirmed by histopathology and electron microscopy. Cell cultures were established from the lungs of these lambs. Replication of a retrovirus in these cultures was demonstrated by the detection in the supernate of SPARV P25. The presence of the retrovirus in the lung fluids from these lambs was also demonstrated. Thus for the first time permanent cell lines that contain the SPARV are available and should considerably facilitate further studies on this virus and the tumour it causes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Sheep tumour cells' study