Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.652696
Title: The pathogenicity of Burkholderia cepacia in cystic fibrosis
Author: Hughes, Jayne
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1998
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Abstract:
This project has focused on the interaction of B. cepacia with neutrophils, the predominant immune cell in CF. As B. cepacia is resistant to neutrophil non-oxidative killing mechanisms, respiratory burst induction by B. cepacia was investigated using another CF pathogen, Pseudomonas aeruginosa, as a comparison. In general, non-opsonised CF isolates of B. cepacia induced little respiratory burst activity. By contrast, P. aeruginosa strains induced a greater range of responses, with a subset of strains inducing considerable activity. Opsonisation with specific immune sera increased neutrophil responses to both B. cepacia and P. aeruginosa. However, in view of the cleavage of opsonins and opsonin receptors within the CF lung, opsonisation may have little impact on host defences to B. cepacia within the respiratory tract. Lipopolysaccharide (LPS) extracted from B. cepacia was shown to upregulate neutrophil expression of complement receptor 3 (CR3) and to prime respiratory burst responses to fMet-Leu-Phe and to whole bacteria. Significantly LPS from the major epidemic strain of B. cepacia, ET12, increased neutrophil respiratory burst responses to P. aeruginosa but not to the ET12 strain itself. Thus it was speculated that B. cepacia may establish a foothold in the P. aeruginosa-infected lung by selectively upregulating immune responses to P. aeruginosa. In view of the development of environmental B. cepacia as biocontrol agents, environmental and clinical isolates were compared for potential virulence determinants. Few obvious differences were found between CF, non-CF clinical and environmental strains. Significantly LPS from two environmental strains of B. cepacia primed neutrophil responses to a similar degree as LPS from CF strains of B. cepacia. A surprising result was that an environmental B. cepacia strain was less effectively cleared in both CF and non-CF mice than the ET12 strain. This project has provided evidence to support the hypothesis that B. cepacia colonisation is associated with a marked and damaging immune response in CF patients.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.652696  DOI: Not available
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