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Disease resistance studies in pigs

Reference	BBS/E/I/00000198
Principal Investigator / Supervisor	Dr Timothy Wallis
Co-Investigators / Co-Supervisors	Dr N Bumstead
Institution	The Pirbright Institute
Department	The Pirbright Institute Department
Funding type	Research
Value (£)	72,423
Status	Completed
Type	Institute Project
Start date	01/04/1997
End date	14/08/1997
Duration	4 months

Abstract

Salmonella-induced macrophage lysis and its significance in pathogenesis/host specificity is unclear. The role of specific virulence genes and the macrophage response to infection is being assessed in Salmonella/macrophage interactions using different Salmonella serotypes and sources of macrophages. Lysis is mediated by factors encoded on both the Salmonella chromosome and virulence plasmid. Two novel loci that influence macrophage lysis have been identified. One locus shows homology to the faeI gene of E. coli that encodes a fimbrial protein. The other locus shows no homology to any sequences on databases. Macrophage lysis is independent of the state of macrophage activation, and not mediated by TNFa. The role of the virulence plasmid in vivo and the significance of macrophage lysis in pathogenesis remain unclear. We have shown that the plasmid influences the recruitment of inflammatory cells to foci of infection in mice, however the Tn mutants that show reduced macrophage lysis in vitro are fully virulent in mice. Salmonella-induce macrophage lysis is both serotype and host dependent. Strains of S. typhimurium, S. dublin but not S. choleraesuis lyse bovine macrophages, while none of these serotypes efficiently lyse porcine macrophages. Salmonella- induced macrophage lysis is not associated with features characteristic of apoptosis. Salmonella persistence within macrophages and associated differential expression of pro- inflammatory cytokines does not correlate with host specificity. Studies characterising Salmonella/macrophages interactions in vivo are ongoing.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	X – not assigned to a current Research Topic
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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