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76. Induction of inflammatory immune responses by Chlamydiae
26
Room
Ahstructs.
Wednesday
ENTRICAN,
‘Moredun
G.,‘*
of inflammatory
WATTEGEDERA,
immune
S.,’ ROCCHI,
M.,’
responses
by Chlamydiae
FLEMING,
D.,2 MAGDALENIC,
V.‘.’
Research Institute. International Research Centre, Pentlands Science Park, Bush Loun, Edinburgh, EH26 ‘MRC Humtrn Reproductive Sciences Unit, 49 Little France. Old Dulkeith Road, Edinhrrgh: ‘Department qf Pathologv, University of Edinburgh Medicul School, Teviot Place, Edinhu~~h, EH9 KAG
Chlatnydia/Chlamydophilu arc obligate, intracellular Gram-negative bacteria that infect a range of hosts. These organisms cause a variety of diseases by targeting particular anatomical sites such as the eye, respiratory tract, genital tract and placenta. Host immune control can be exerted through production of interferon-gamma (IFN-y). However, persistent infection is common and often accompanied by immuno-pathological sequelae that lead to chronic disease. In order to understand the factors that lead to chronic disease it is important to define the host-pathogen relationship, particularly during both the acute phase of infection. We have used quantitative real-time PCR
OPZ,
and ELISA to analyse the production of inflammatory mediators by epithelial cells in the early stages of infection and found an increase in the expression of interleukin-8 (IL-g) and of the natural antimicrobial secretory leukocyte protease inhibitor (SLPI). Analysis of molecules that are involved in pathogen recognition by the innate immune system, such as Toll-like receptors (TLRs) and CD14, revealed that Chlamydiae do not appear to activate epithelial cells via lipopolysaccharide binding to TLR-4ICD14. These observations will be linked to intracellular pathways involved in the control of Chlamydial growth.
A: 14.30-15.00
77. Bovine
viral
diarrhoea
virus evasion of the innate MCCAULEY,
Institute
ftir Animal Heulth,
Compton
Laboratop
Pestiviruses have unusual lifestyles; they are able to infect a foetus and establish a persistent infection in the absence of an immune response to the virus. These persistently infected animals are the source of acute infection. In order to establish the persistent infection not only does the virus have to avoid the acctuired immune response: it also has to avoid stimulating an antiviral response in the’ host.’ Bovine viral diarrhoea virus able to sustain infection in persistently infected calves
Room
2003
A: 14.00-14.30
76. Induction
Room
16th April
immune
responses
of the host
J.*
Compton.
Newbuq
Berkshire,
RG20
7NN
is non-cytopathogenic and, importantly, also fails to stimulate an interferon response. The failure to induce interferon in foetal infections is likely to reflect its behaviour in cultured cells. In culture, interferon-beta transcription is inhibited through inhibition of the transcriotion factor IRF3. In addition. BVDV inhibits dsRNA-induced stimulafion of interferon-beta transcription. It is likely that these antiinnate immune responses are crucial for virus survival.
A: 1.5.00-15.30
78. The exploitation
of the genome
in the search for determinants LEIGH,
J.A.,**
WARD,
Despite the control of contagious routes of infection, bovine mastitis remains one of the most common diseases of dairy cattle. The organisms most frequently encountered in the UK are E. coli and S. uberis, both of which infect the mammary gland from environmental reservoirs. Due to the limited number of bacterial species that are now frequently involved, vaccines aimed at individual species can be considered to be able to make a significant impact on the incidence of mastitis. However, the development of such products is hampered by a lack of information on the host pathogen interactions that promote infection and disease. Sequencing of the genome of S uberis began at the Sanger Institute in 2002 and coincided with the development of technology at IAH that enabled the production of mutants of this organism lacking individual genes. A bank of around
P.N., FIELD,
of virulence
in Streptococcus
u&v-is
T.R.
10,000 individual, single-gene mutants has been produced. This represents a population that, on average, contains a genetic lesion every 200 bp. This bank has been screened for mutants with altered phenotypes, enabling the isolation of isogenic strains that lack capsule, are unable to grow in milk, and are unable to activate bovine plasminogen. The ability of these mutants to cause disease has been assessed in the host species. This has led to an unequivocal demonstration of the role of these attributes in the pathogenesis of disease. The further development of these procedures to permit the isolation of mutants based solely on genotypic lesions will permit the identification of further bacterial components that are essential for virulence and which may be used as potential vaccine candidates to protect against intra-mammary infection by this organism.
Room
Ahstructs.
Wednesday
ENTRICAN,
‘Moredun
G.,‘*
of inflammatory
WATTEGEDERA,
immune
S.,’ ROCCHI,
M.,’
responses
by Chlamydiae
FLEMING,
D.,2 MAGDALENIC,
V.‘.’
Research Institute. International Research Centre, Pentlands Science Park, Bush Loun, Edinburgh, EH26 ‘MRC Humtrn Reproductive Sciences Unit, 49 Little France. Old Dulkeith Road, Edinhrrgh: ‘Department qf Pathologv, University of Edinburgh Medicul School, Teviot Place, Edinhu~~h, EH9 KAG
Chlatnydia/Chlamydophilu arc obligate, intracellular Gram-negative bacteria that infect a range of hosts. These organisms cause a variety of diseases by targeting particular anatomical sites such as the eye, respiratory tract, genital tract and placenta. Host immune control can be exerted through production of interferon-gamma (IFN-y). However, persistent infection is common and often accompanied by immuno-pathological sequelae that lead to chronic disease. In order to understand the factors that lead to chronic disease it is important to define the host-pathogen relationship, particularly during both the acute phase of infection. We have used quantitative real-time PCR
OPZ,
and ELISA to analyse the production of inflammatory mediators by epithelial cells in the early stages of infection and found an increase in the expression of interleukin-8 (IL-g) and of the natural antimicrobial secretory leukocyte protease inhibitor (SLPI). Analysis of molecules that are involved in pathogen recognition by the innate immune system, such as Toll-like receptors (TLRs) and CD14, revealed that Chlamydiae do not appear to activate epithelial cells via lipopolysaccharide binding to TLR-4ICD14. These observations will be linked to intracellular pathways involved in the control of Chlamydial growth.
A: 14.30-15.00
77. Bovine
viral
diarrhoea
virus evasion of the innate MCCAULEY,
Institute
ftir Animal Heulth,
Compton
Laboratop
Pestiviruses have unusual lifestyles; they are able to infect a foetus and establish a persistent infection in the absence of an immune response to the virus. These persistently infected animals are the source of acute infection. In order to establish the persistent infection not only does the virus have to avoid the acctuired immune response: it also has to avoid stimulating an antiviral response in the’ host.’ Bovine viral diarrhoea virus able to sustain infection in persistently infected calves
Room
2003
A: 14.00-14.30
76. Induction
Room
16th April
immune
responses
of the host
J.*
Compton.
Newbuq
Berkshire,
RG20
7NN
is non-cytopathogenic and, importantly, also fails to stimulate an interferon response. The failure to induce interferon in foetal infections is likely to reflect its behaviour in cultured cells. In culture, interferon-beta transcription is inhibited through inhibition of the transcriotion factor IRF3. In addition. BVDV inhibits dsRNA-induced stimulafion of interferon-beta transcription. It is likely that these antiinnate immune responses are crucial for virus survival.
A: 1.5.00-15.30
78. The exploitation
of the genome
in the search for determinants LEIGH,
J.A.,**
WARD,
Despite the control of contagious routes of infection, bovine mastitis remains one of the most common diseases of dairy cattle. The organisms most frequently encountered in the UK are E. coli and S. uberis, both of which infect the mammary gland from environmental reservoirs. Due to the limited number of bacterial species that are now frequently involved, vaccines aimed at individual species can be considered to be able to make a significant impact on the incidence of mastitis. However, the development of such products is hampered by a lack of information on the host pathogen interactions that promote infection and disease. Sequencing of the genome of S uberis began at the Sanger Institute in 2002 and coincided with the development of technology at IAH that enabled the production of mutants of this organism lacking individual genes. A bank of around
P.N., FIELD,
of virulence
in Streptococcus
u&v-is
T.R.
10,000 individual, single-gene mutants has been produced. This represents a population that, on average, contains a genetic lesion every 200 bp. This bank has been screened for mutants with altered phenotypes, enabling the isolation of isogenic strains that lack capsule, are unable to grow in milk, and are unable to activate bovine plasminogen. The ability of these mutants to cause disease has been assessed in the host species. This has led to an unequivocal demonstration of the role of these attributes in the pathogenesis of disease. The further development of these procedures to permit the isolation of mutants based solely on genotypic lesions will permit the identification of further bacterial components that are essential for virulence and which may be used as potential vaccine candidates to protect against intra-mammary infection by this organism.