Résumé
ABSTRACT Bacillus anthracis strain SPV842_15 was isolated from bovine fetus, while B. anthracis strain Brazilian vaccinal was recovered from a commercial vaccine. We report here the genome sequences of both strains. The SPV842_15 genome is composed of a single circular chromosome with a length of 5,228,664 base pairs, and comprises 5911 coding sequences. In turn, the Brazilian vaccinal genome remains in 201 contigs with 5733 coding sequences. Both genomes have an overall C + G content of 35.4%, and 11 genes encoding the ribosomal RNAs (rRNAs) 5S, 16S and 23S. Only the plasmid pX01 sequence, which carries genes for toxins synthesis, was detected and completely assembled for both strains. These plasmids have a length of 181,684 base pairs and a C + G content of 32.5%. These genomic data generate insights about vaccinal B. anthracis virulence.
Sujets)
Animaux , Bovins , Bacillus anthracis/isolement et purification , Bacillus anthracis/génétique , Vaccins antibactériens/génétique , Maladies des bovins/microbiologie , Génome bactérien , Phylogenèse , Plasmides/génétique , Bacillus anthracis/classification , Composition en bases nucléiques , ADN bactérien/génétique , Données de séquences moléculaires , Vaccins antibactériens/isolement et purification , Séquence nucléotidiqueRésumé
Genetically attenuated microorganisms, pathogens, and some commensal bacteria can be engineered to deliver recombinant heterologous antigens to stimulate the host immune system, while still offering good levels of safety. A key feature of these live vectors is their capacity to stimulate mucosal as well as humoral and/or cellular systemic immunity. This enables the use of different forms of vaccination to prevent pathogen colonization of mucosal tissues, the front door for many infectious agents. Furthermore, delivery of DNA vaccines and immune system stimulatory molecules, such as cytokines, can be achieved using these special carriers, whose adjuvant properties and, sometimes, invasive capacities enhance the immune response. More recently, the unique features and versatility of these vectors have also been exploited to develop anti-cancer vaccines, where tumor-associated antigens, cytokines, and DNA or RNA molecules are delivered. Different strategies and genetic tools are constantly being developed, increasing the antigenic potential of agents delivered by these systems, opening fresh perspectives for the deployment of vehicles for new purposes. Here we summarize the main characteristics of the different types of live bacterial vectors and discuss new applications of these delivery systems in the field of vaccinology.
Sujets)
Animaux , Humains , Vaccins antibactériens/immunologie , Vecteurs de médicaments , Infections bactériennes/prévention et contrôle , Vaccins antibactériens/génétique , Tumeurs/thérapie , Organismes génétiquement modifiés/génétique , Organismes génétiquement modifiés/immunologie , Vaccins atténués/génétique , Vaccins atténués/immunologieRésumé
Corynebacterium pseudotuberculosis, a Gram-positive intracellular pathogen, is the etiological agent of caseous lymphadenitis or CLA. This bacterium infects goats and sheep and causes great economic losses worldwide annually, mainly for goat producers. Despite its importance, CLA is still poorly characterized. However, with advances in the genomic field, many C. pseudotuberculosis genes have already been characterized, mainly those related to virulence such as phospholipase D. Here, we examined the use of the several available genes of C. pseudotuberculosis and reviewed their applications in vaccine construction, more efficient diagnostics for CLA, and control of this disease, among other applications.
Sujets)
Animaux , Corynebacterium pseudotuberculosis/génétique , Infections à Corynebacterium/diagnostic , Corynebacterium pseudotuberculosis/immunologie , Corynebacterium pseudotuberculosis/pathogénicité , Infections à Corynebacterium/immunologie , Infections à Corynebacterium/microbiologie , Vaccins antibactériens/génétique , Vaccins antibactériens/immunologie , Virulence/génétiqueRésumé
Anaplasmosis is a bovine intraerythrocytic disease caused by the bacterium Anaplasma marginale; it causes significant economic losses in tropical and subtropical regions, worldwide. The msp4 gene of an A. marginale strain isolated in Paraná, Brazil, was amplified by PCR and sequenced; its cloning into the pET102/D-TOPO® vector produced an msp4-6xHis-V5-HP thioredoxin fusion gene construct. This recombinantclone was over-expressed in Escherichia coli BL21(DE-3); the expressed fusion protein was found almost entirely in the insoluble form (inclusion bodies) in the cell lysate. The inclusion bodies were solubilized with urea and the recombinant protein was purified by Ni-NTA column and dialyzed. This method produced a relatively high yield of rMSP4, which was used to immunize rabbits. The deduced amino acid sequence encoded by MSP4 showed 99% homology to A. marginale isolates from Florida, USA, and from Minas Gerais, Brazil. Both rMSP4 and native MSP4 were recognized by post- immunization rabbit serum, showing that rMSP4 has conserved epitopes. As antigenicity was preserved, rMSP4 might be useful for the development of vaccine against anaplasmosis.