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Title: Identification and characterisation of novel antigens from the sheep scab mite, Psoroptes ovis
Author: McNair, Carol
ISNI:       0000 0001 3388 4533
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2004
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Despite attempts to control sheep scab, it remains a problem in the UK. The disease is controlled by chemical dips, but these have several drawbacks. Certain strains of the causative agent, Psoroptes avis, are developing resistance to these, and there are also concerns over their safety. Clearly, an alternative control method is needed, with one possibility being avaccine.!- In this project, a variety of molecular and proteomic techniques were utilised to identify candidate vaccine antigens for the control of sheep scab. Cysteine proteases were found to be highly active in mite extracts, and cathepsin B was localised to the surface of the mit~' s gut, suggesting a role in digestion and making it a putative hidden antigen. Antioxidant activity was investigated in mite extracts, and recombinant proteins were expressed. Thioredoxin peroxidase was localised to an area around the mite's pharynx, which could represent salivary glands; and was also recognised by sera from sheep infected with P. avis. This suggests this enzyme may be secreted by the mite and interact with the host immune response in some way. A suppressive subtractive hybridisation study was carried out to identify genes upregulated ' by mites during feeding, and thus may encode proteins involved in digestion. This identified a number of interesting genes, including homologues of house dust mite antigens, salivary gland proteins and proteins with possible roles in immunomodulation. An in situ hybridisation protocol was used on mite sections to localise mRNA of several genes characterised elsewhere in this study. Although this technique was not entirely successful, there were some positive results which provide the groundwork for future attempts to optimise this technique in this parasite. Overall, this thesis has identified several potential antigens, both hidden and exposed, which could be tested in a vaccine trial for sheep scab in the future.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available