Propriétés hémagglutincmtes du «virus» de l'avortement enzootique des petits ruminants (souches de «Rakeia» d'origine ovine et caprine). Note préliminaire

Faye, P.; Charton, André; Mage, C.; Bernard, C.; Layec, Cl. Le

doi:10.4267/2042/66351

Cited by 13 publications

(10 citation statements)

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“…No discrimination between the new isolates and the reference strain AB7 isolated in France from an ovine abortion [10], was demonstrated using either PCR-RFLP of the 16S-23S RNA intergenic spacer or MIF. These methods have been used to characterise chlamydial strains [7,9,13] and to type C. trachomatis with relative ease.…”

Section: Discussionmentioning

confidence: 84%

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Isolation and characterisation of local strains of Chlamydophila abortus (Chlamydia psittaci serotype 1) from Tunisia

Rekiki

Sidi-Boumedine²,

Souriau³

et al. 2002

Vet. Res.

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-Chlamydiosis is one of the major diseases that can lead to abortion in ewes. Since 1997, in 5 regions of Tunisia, Chlamydia-related abortions have been reported in 15 sheep and goat flocks. One hundred and sixty-six sera and 50 vaginal swab samples were collected from adult ewes. Chlamydial antigens were detected in 29 (58%) of the vaginal swabs using Enzyme Linked Immunsorbent Assay (ELISA) while 9 (18%) were positive by cell culture. Five strains were recovered from 4 different sheep flocks. Monoclonal antibody profiles and restriction fragment length polymorphism (RFLP) analysis of the 16S-23S rRNA spacer region showed that these isolates were C. abortus. Using amplified fragment length polymorphism (AFLP), these Tunisian strains were shown to exhibit the same pattern as strains isolated in France.Chlamydiosis / diagnosis / Tunisia / isolation / characterisation Résumé -Isolement et typage de souches locales de Chlamydophila abortus (Chlamydia psittaci sérotype 1). La chlamydiose est une des principales cause d'avortements infectieux en Tunisie. Lors de la période d'agnelage de 1997, 166 prises de sang et 50 écouvillons vaginaux ont été prélevés dans 15 troupeaux répartis sur 5 gouvernorats et ayant eu des problèmes d'avortements. Des chlamydia ont été mises en évidence dans 29 (58 %) écouvillons vaginaux appartenant à 13 troupeaux différents par ELISA directement sur l'écouvillon vaginal et 9 (18 %) après multiplication sur cellules. Cinq souches tunisiennes appartenant à 4 troupeaux différents ont ainsi pu être isolées. Leur caractérisation par une panoplie d'anticorps monoclonaux et par étude du profil de restriction de l'espace intergé-nique 16S-23S a démontré qu'elles appartenaient toutes à l'espèce Chlamydophila abortus. Par 215 Vet. Res. 33 (2002) 215-222

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Section: Discussionmentioning

confidence: 84%

“…The amplified products were separated by standard horizontal gel electrophoresis on a 1.5% agarose gel in electrophoresis buffer and stained with an ethidium bromide solution. In addition to the 5 isolates, AB7 was used as reference strain for C. abortus [10], as well as iB1 strain for C. pecorum [16].…”

Section: Amplified Fragment Length Polymorphism (Aflp)mentioning

confidence: 99%

Isolation and characterisation of local strains of Chlamydophila abortus (Chlamydia psittaci serotype 1) from Tunisia

Rekiki

Sidi-Boumedine²,

Souriau³

et al. 2002

Vet. Res.

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“…The virulent C. abortus AB7 ovine abortion strain isolated from an ovine abortion [7] and the vaccinal 1B strain obtained by selection of a temperature-sensitive mutant after nitrosoguanidine mutagenesis of C. abortus AB7 [12] were used. Bacteria were propagated in the yolk sac of embryonated SPF chicken eggs inoculated at day 7, purified as previously described [3] and stored at -70°C.…”

Section: Abortus Strainsmentioning

confidence: 99%

Proteic boost enhances humoral response induced by DNA vaccination with the dnaK gene of Chlamydophila abortus but fails to protect pregnant mice against a virulence challenge

Héchard¹,

Grépinet²,

Rodolakis³

2003

Vet. Res.

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-In order to enhance the quantity and the protective properties of the antibodies induced by DNA vaccination with the heat shock protein dnaK gene of Chlamydophila abortus AB7 as well as to elicit an efficient cellular immune response, we vaccinated mice with a DNA prime followed by a boost with the recombinant DnaK protein. In non-pregnant mice, this strategy induced the same predominance of the IgG2a isotype as DNA immunization alone with a substantial increased antibody level. The induced antibodies had no in vitro neutralizing properties on C. abortus infectivity. Moreover, the proteic boost probably failed to elicit an efficient cellular immune response since the pregnant or non-pregnant mice were not protected against the bacterial challenge.DNA immunization / proteic boost / Chlamydophila abortus / DnaK / Hsp70

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“…The C. abortus vaccine is based on a live attenuated strain obtained by nitrosoguanidine (NTG) mutagenesis of the virulent strain AB7, isolated from an aborted lamb (8). NTG causes mutations by methylation of nucleotides, especially of guanine, which can then pair with thymine or cytosine (16), giving rise to a GC-to-AT conversion.…”

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confidence: 99%

Genomic Analysis of an Attenuated Chlamydia abortus Live Vaccine Strain Reveals Defects in Central Metabolism and Surface Proteins

et al. 2009

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Comparative genomic analysis of a wild-type strain of the ovine pathogen Chlamydia abortus and its nitrosoguanidine-induced, temperature-sensitive, virulence-attenuated live vaccine derivative identified 22 single nucleotide polymorphisms unique to the mutant, including nine nonsynonymous mutations, one leading to a truncation of pmpG, which encodes a polymorphic membrane protein, and two intergenic mutations potentially affecting promoter sequences. Other nonsynonymous mutations mapped to a pmpG pseudogene and to predicted coding sequences encoding a putative lipoprotein, a sigma-54-dependent response regulator, a PhoH-like protein, a putative export protein, two tRNA synthetases, and a putative serine hydroxymethyltransferase. One of the intergenic mutations putatively affects transcription of two divergent genes encoding pyruvate kinase and a putative SOS response nuclease, respectively. These observations suggest that the temperature-sensitive phenotype and associated virulence attenuation of the vaccine strain result from disrupted metabolic activity due to altered pyruvate kinase expression and/or alteration in the function of one or more membrane proteins, most notably PmpG and a putative lipoprotein.The Chlamydiaceae represent a group of obligate intracellular bacteria responsible for a wide range of diseases in many different hosts with significant and broad economic and public health impacts. Despite the global impact of chlamydial disease, vaccines are available for only two chlamydial species, Chlamydia abortus and Chlamydia felis, which infect ovine and feline species, respectively. A formalin-inactivated vaccine against C. abortus infection, which in the United Kingdom costs the agricultural industry an estimated £20 million each year (2), was developed in the 1960s but did not offer complete protection and required revaccination every 3 years. This vaccine subsequently became demonstrably ineffective when C. abortus infections occurred in vaccinated flocks in the late 1970s (1, 14). Although inactivated vaccines are still used, more effective C. felis and C. abortus vaccines derived from live attenuated strains are also available. However, C. felis reinfection is not completely controlled with the live attenuated C. felis vaccine, as vaccinated animals still shed chlamydiae (32). In contrast, the live attenuated C. abortus vaccine blocks reinfection and shedding (24, 25).The C. abortus vaccine is based on a live attenuated strain obtained by nitrosoguanidine (NTG) mutagenesis of the virulent strain AB7, isolated from an aborted lamb (8). NTG causes mutations by methylation of nucleotides, especially of guanine, which can then pair with thymine or cytosine (16), giving rise to a GC-to-AT conversion. Other nucleotide substitutions are seen less frequently with deletions resulting from lesion repair. Treatment of AB7 with NTG produced two temperature-sensitive mutants, 1B and 1H, which were attenuated in the mouse model (21). Unlike 1H, which was unstable in temperature-sensitive growth studies, the ...

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Propriétés hémagglutincmtes du «virus» de l'avortement enzootique des petits ruminants (souches de «Rakeia» d'origine ovine et caprine). Note préliminaire

Abstract: Propriétés hémagglutinantes du «virus» de l'avortement enzootique des petits ruminants (souches de « Rakeia » d'origine ovine et caprine). Note préliminaire par MM.

Cited by 13 publications

References 0 publications

Isolation and characterisation of local strains of Chlamydophila abortus (Chlamydia psittaci serotype 1) from Tunisia

Isolation and characterisation of local strains of Chlamydophila abortus (Chlamydia psittaci serotype 1) from Tunisia

Proteic boost enhances humoral response induced by DNA vaccination with the dnaK gene of Chlamydophila abortus but fails to protect pregnant mice against a virulence challenge

Genomic Analysis of an Attenuated Chlamydia abortus Live Vaccine Strain Reveals Defects in Central Metabolism and Surface Proteins

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