No description available.

<p>Despite the advanced knowledge of the mechanisms of influenza infection and improved vaccines, Influenza A Virus still causes a life-threatening respiratory disease, especially during pandemics. Past investigations have proposed a synergism between Influenza A virus and a simultaneous or subsequent bacterial superinfection as the predominant cause of death. The recent development of animal models to study these heterologous infections has shed light onto the diverse mechanisms by which Influenza A Virus may increase the susceptibility to contract a secondary bacterial infection. These studies suggested an important role for the innate immune system in mediating such disease. We developed a model of heterologous infection combining Influenza A Virus and <em>Bordetella parapertussis</em> that demonstrated a critical role for MIP-2 to drive pulmonary neutrophilia in the pathology associated with bacterial superinfection of influenza. However, the origin of this increased MIP-2 production and the mechanisms underlying the immunopathology remained to be elucidated. The present studies proposed IL-1β overproduction as the upstream cause of the increased MIP-2 production observed in heterologous infection. This exaggerated IL-1β production was likely related to the increased bacterial burden observed in heterologously infected mice. This study also demonstrated that reduction in IL-1β production by blockade of the inflammasome seemed to provide an improvement in the clinical symptoms and the immunopathology of the disease. Thus, interventions to attenuate the exacerbated bacterial burden and the inflammatory responses derived from the subsequent IL-1β overproduction should be further investigate as possible therapeutic approaches to treat bacterial superinfections.</p> / Master of Science (MSc)

La toxine de pertussis (PTX) est une A-B protéine considérée comme l’un des principaux facteurs de virulence de Bordetella pertussis, l’agent bactérien responsable de la coqueluche. Aujourd’hui, cette maladie représente encore un réel danger pour les nouveaux-nés et les<p>nourrissons non ou partiellement immunisés. Actuellement, la coqueluche provoque encore la<p>mort d’environ 350.000 individus par an. La toxicité de la PTX est liée à l’activité<p>enzymatique de sa sous-unité A capable d’inhiber les voies de signalisation associées aux<p>protéines Gi. La partie B, quant à elle, permet l’entrée de cette sous-unité A dans le<p>cytoplasme des cellules cibles en se liant spécifiquement à son ou ses récepteurs<p>membranaires toujours inconnus de nos jours.<p><p>Des études réalisées chez la souris et chez l’homme ont montré que les vaccins anticoquelucheux combinés à différents antigènes vaccinaux étaient capables de moduler<p>leurs réponses humorales spécifiques. Par ailleurs, la PTX est couramment qualifiée d’agent<p>immunostimulant. En effet, des modèles murins de vaccination permirent d’identifier des<p>propriétés adjuvantes de la PTX coadministrée avec des antigènes non relevants.<p><p>Le travail développé dans ce manuscrit étudie les effets de la PTX sur 2 types cellulaires<p>primordiaux sollicités lors d’une vaccination :la cellule dendritique (DC) et le lymphocyte T<p>CD4+ naïf.<p><p>Les DC sont les seules cellules présentatrices d’antigènes aptes à initier une réponse immune<p>primaire. Dans un premier temps, nous avons montré que la PTX était capable d’activer des<p>DC générées in vitro à partir de monocytes. En effet, elles acquièrent un phénotype mature<p>caractérisé par une augmentation de l’expression membranaire des molécules costimulatrices<p>et du CMH de classe II, démontrant un effet direct et spécifique de la PTX sur les DC<p>myéloïdes. Parallèlement, ces DC produisent du TNF-a, de l’IL-12p40 et de l’IL-12p70 et<p>activent NF-kappaB, un facteur de transcription essentiel au processus de maturation. Nous<p>avons obtenu des résultats similaires avec une toxine génétiquement modifiée qui est<p>enzymatiquement inactive. A partir de sang total incubé avec la PTX, nous avons par ailleurs<p>observé que les DC circulantes du nouveau-né étaient déficientes dans leur maturation et leur<p>sécrétion d’IL-12p70 comparées aux DC de l’adulte.<p><p>D’autre part, il a été décrit précédemment que la PTX exerçait des effets mitogènes sur les<p>lymphocytes T humains et murins. Cependant, le rôle qu’elle joue sur la population des<p>lymphocytes T CD4 naïfs reste peu connu. A l’issue de notre second travail, nous pouvons<p>dès lors affirmer que la PTX est également capable d’activer des lymphocytes T<p>CD4+CD45RA+ naïfs isolés à partir des cellules mononuclées du sang périphérique, et ce<p>indépendamment de son activité enzymatique. En effet, ces lymphocytes T CD4+ naïfs stimulés par la PTX prolifèrent, synthétisent des quantités non négligeables d'ARN messagers<p>codant pour l’IL-2 et le TNF-a, augmentent l’expression membranaire des molécules CD40L,<p>CD69 et CD25 et expriment la protéine Foxp3. Cette activation s’accompagne de la translocation nucléaire de NF-kappaB et NFAT. Parallèlement à l’adulte, la PTX active les lymphocytes T CD4 néonataux. Néanmoins, ceux-ci prolifèrent moins bien et expriment plus faiblement le CD40L à leur surface.<p><p>Enfin, la PTX induit la sécrétion de taux importants d’IFN-g par des T CD4+CD45RA+ naïfs<p>adultes mis en présence de DC autologues.<p><p>Nous terminerons en proposant l’hypothèse suivante :La PTX pourrait exercer ses propriétés<p>adjuvantes par l’intermédiaire de différents mécanismes comprenant notamment la maturation<p>des DC d’origine myéloïde et l’activation des lymphocytes T CD4+CD45RA+ naïfs. Ces 2 populations cellulaires sont en effet les principaux protagonistes impliqués dans la réponse<p>immune primaire. / Doctorat en sciences pharmaceutiques / info:eu-repo/semantics/nonPublished

Bordetella pertussis is a strictly human pathogen colonizing the upper respiratory tract, causing a respiratory disease known as whooping cough or pertussis. The introduction of whole-cell vaccines and acellular vaccines, resulted in a significant reduction in the incidence of disease and reduce the fatalities associated with infection. However, epidemiological data show a significant increase in the incidence of the disease in recent decades. The increasing incidence is mainly attributed to the transition from the whole- cell vaccine to an acellular vaccine. Based on research from recent years has shown that acellular vaccines have many drawbacks, and it is therefore necessary to change the vaccination strategy. One possible solution to the situation is the development of a new generation of whole-cell vaccines with reduced reactogenicity. The new whole-cell vaccine was prepared by a genetically modified B. pertussis strain. B. pertussis was modified using allelic exchange to develop strain encoding enzymatically inactive pertussis toxin, modified lipid A and lacking dermonecrotic toxin. This combination of genetic modifications in mice led to a decrease in reactogenicity test vaccine in vivo. In case of intranasal infection whole-cell vaccine containing genetically modified strain is providing...

Bordetella pertussis is an important human pathogen that causes an infection disease called whooping cough. This gram-negative bacterium produces an adenylate cyclase toxin (CyaA) that recognizes an integrin receptor CD11b/CD18 present on the surface of myeloid phagocytes and delivers an adenylate cyclase (AC) domain into the cell cytosol. This thesis deals with the endocytic machinery of CyaA and its potential use as a specific marker for endocytosis of the CD11b/CD18 receptor molecule. Detoxified mutant of CyaA, CyaA-AC- , that has the capacity to promote calcium influx as well the potassium efflux, was shown to trigger activation of the integrin receptor CD11b/CD18 followed with endocytic uptake by clathrin-dependent pathway. On the other side, the inactive mutant CyaA-KP-AC- that is unable to provoke integrin activation was endocytosed by clathrin-independent pathway. These results suggest that the various endocytic pathways of the CD11b/CD18 are determined by different conformational states of the receptor molecule.

Bordetella bronchiseptica é um agente respiratório zoonótico comumente encontrado em diversars espécies animais domésticos como cães, gatos, coelhos, suínos, aves e equinos. As infecções em humanos ocorrem ocasionalmente, sendo descritas com maior freqüência em indivíduos imunocomprometidos, mas relatos de casos de doença em adultos saudáveis e crianças têm aumentado. O presente estudo teve como objetivos determinar o perfil de resistência antimicrobiana de cepas de B. bronchiseptica isoladas de cães, gatos, coelhos e suínos, caracterizar as cepas pela eletroforese em campo pulsado (PFGE), e comparar os resultados obtidos com os dados epidemiológicos. Foram avaliadas 145 cepas e estas apresentaram 100% de resistência a ampicilina, penicilina, espectinomicina, clindamicina, tiamulina e tilosina. Taxas de resistência superiores a 95% das cepas foram observadas frente a tilmicosina, danofloxacina e ceftiofur. Os antimicrobianos com menores taxas de resistência foram enrofloxacina (2,1%) e clortetraciclina (11 %). As cepas isoladas de coelhos apresentaram menores taxas de resistência que as de suínos e de animais de companhia. A caracterização das cepas pela PFGE permitiu a separação de acordo com as espécies de origem em diferentes pulsotipos. A caracterização do agente, principalmente no que se refere à resistência a antimicrobianos, será de grande utilidade para os veterinários no controle das infecções pelo mesmo em suínos, animais de companhia e coelhos, visto que os dados sobre este agente etiológico no Brasil são escassos / Bordefella bronchisepfica is a zoonotic respiratory agent commonly found in domestic animais as dogs, cats, rabbit, swine, birds and horses, Infections in humans occur rarely and have been described more frequently in immunocompromised individuais, but reports of cases of illness in healthy adults and children have increased. This study aims to characterize the resistance profile of B. bronchiseptica strains isolated from dogs, cats, rabbits and pigs and evaluate the strains by pulsed field gel electrophoresis (PFGE), comparing the results with epidemiological data. From 145 strains tested 100% presented resistance to ampicillin, penicillin, spectinomycin, clindamycin, tiamulin and tylosin. Resistance rates higher than 95% were found against tilmicosin, danofloxacin and ceftiofur. The antimicrobials with lower resistance rates were enrofloxacin (2.1 %) and chlortetracycline (11 %). Strains isolated from rabbits presented low resistance rates when compared with swine and pet animais. The PFGE analysis separated the strains according specie of origin in different pulsotypes. The agent characterization, mainly in relation with antimicrobial resistance will be of great help to veterinarians in control of infections in swine, pets and rabbits, since data about this bacteria in Brazil are rare

La protéine CyaA est un facteur de virulence majeur de Bordetella pertussis, impliqué dans la maladie de la coqueluche. Le domaine catalytique AC de CyaA est directement transféré dans la cellule hôte eucaryote, où il est activé comme adénylcyclase par la calmoduline, une protéine ubiquitaire et sensible aux ions calcium. Ainsi, AC transforme l'ATP en AMPc de manière incontrôlée, ce qui conduit à des dérèglements cellulaires. Seule la structure de AC complexé à la calmoduline chargée d'ions calcium avait été résolue par cristallographie aux rayons X. À partir de cette structure, des simulations de dynamique moléculaire de AC libre, et en complexe avec la calmoduline nous ont permis de caractériser l'effet de la calmoduline et des ions calcium sur la plasticité conformationnelle du complexe. Les tendances conformationelles de AC libre ont aussi été étudiées. L'analyse conjointe des influences énergétiques et des liaisons hydrogène a révélé un réseau d'interactions entre AC et la calmoduline, dans lequel trois résidus clés, susceptibles de jouer un rôle allostérique sur l'activité de l'adénylcyclase ont été modifiés par mutagenèse dirigée. Ces tests expérimentaux ont conduits à la mise en évidence d'une région allostérique qui assure la communication de l'information de transition conformationnelle entre le site de fixation de la calmoduline et le site catalytique. Une exploration conformationnelle plus approfondie de AC à l'état non-lié a été entreprise par une méthode innovante de dynamique accélérée par la température (TAMD). Elle nous a conduit à la prédiction de conformations échantillonnées de AC dans son état libre. Ces prédictions pourraient être utilisées à l'avenir pour stabiliser l'état libre et faciliter l'étude expérimentale de sa structure

The genus Bordetella contains several pathogenic species generally associated with upper respiratory tract infections in warm-blooded animals. Bordetella pertussis is the etiologic agent of whooping cough. Whooping cough is presently one of the ten most common causes of death from infectious diseases and reported by the World Health Organisation (WHO) to cause 50 million cases and 350000 deaths worldwide per year, mainly among unvaccinated individuals in poor countries. The term proteome, in analogy to the term genome, was coined to describe the complete set of proteins that an organism has produced under a defined set of conditions. Proteomics has been used to identify novel bacterial vaccine candidates against several human pathogens. Fueled by growing DNA sequence information, the analysis of the proteome becomes a valuable and useful tool for antigen discovery. Much of information about immunogenic component can be derived from proteomics coupled to Western blotting, namely immunoproteomics. v In the present study, we report first immunoproteomics analysis to identify candidate antigens of B. pertussis for vaccine development. Different sera from mice, which were immunized or challenged with B. pertussis, were analyzed for reactivity by Western blot against whole cell extracts of B. pertussis Tohama and Saadet strains separated by 2-DE. We identified 15 immunogenic proteins of Bordetella pertussis as a total (60 kDa chaperonin, heat shock protein, serum resistance protein, putative substrate-CoA ligase, ATP-dependent protease, preprotein translocase secA subunit, S-adenosylmethionine synthetase, elongation factor Tu, RNA polymerase alpha subunit, ketol-acid reductoisomerase, pertactin, lysyl-tRNA synthetase, serum resistance protein, carbamoyl-phosphate synthase large chain, 30S ribosomal protein S1 subunit), 6 of which being identified as immunogenic in a pathogenic microbe (ATP-dependent protease, carbamoylphosphate synthase large chain, lysyl-tRNA synthetase, putative chromosome partition protein, preprotein translocase secA subunit, 30S ribosomal protein S1 subunit) and 5 identified as immunogenic for Bordetella pertussis (RNA polymerase alpha subunit, S-adenosylmethionine synthatase, putative substrate-CoA ligase, elongation factor Tu, ketol-acid reductoisomerase) for the first time.

Whooping cough (pertussis) is a highly contagious acute respiratory disease caused by the strict human pathogen Bordetella pertussis, a gram-negative coccobacillus. The worldwide mass-vaccination was started in 1940s and to date, a number of whole-cell (Pw) and acellular pertussis vaccine (Pa) formulations were developed. Yet the current vaccines are incapable of providing sustained, lifelong immunity and eliminating subclinical infections, which pose a threat especially for unimmunized infants as well as adolescents and adults. Thus, finding new protein candidates with high immune protective capacities is necessary to enhance the clinical efficacy of current acellular pertussis (Pa) vaccines. In this study, iron-superoxide dismutase (FeSOD) protein was investigated for its capacity of conferring protectivity as well as stimulating humoral and cellular responses against B. pertussis infection in a mouse model. For this purpose, sodB gene, which encodes iron-superoxide dismutase FeSOD protein, was amplified from the genomic DNA of the universal B. pertussis strain &lsquo / Tohama I&rsquo / and sequentially cloned to pGEM&reg / -T subcloning and pET-28a(+) expression vectors. Afterwards sodb/pET28a(+) construct was introduced to E. coli BL21(DE3) cells and the gene was overexpressed therein via IPTG induction. The expressed FeSOD protein was then purified by affinity chromatography and its previously reported immunogenicity was confirmed by Western blot. After filter-sterilization, the protein was adsorbed to alum [Al(OH)3] adjuvant and introduced to BALB/c twice at three weeks intervals intraperitoneally at a concentration of 20 &mu / g purified FeSOD protein/mouse. Another group of mice were immunized in tandem with heat-inactivated whole-cell suspension of B. pertussis. Ten days after the second immunization, mice were intranasally challenged with the local &lsquo / Saadet&rsquo / strain of B. pertussis. Next the lungs of groups of mice were excised, homogenized and plated as serial dilutions on days 5, 8 and 14 post-challenge, and viable lung CFU counts were carried out. Whole cell immunization conferred complete bacterial clearance following B. pertussis intranasal infection while FeSOD immunization failed to attain such protection. In addition to the protectivity assay, ELISA was performed to assess the humoral (i.e. IgG) immune response triggered upon FeSOD- and whole-cell immunizations and a statistically significant increase in anti-FeSOD IgG production was observed in FeSOD-immunized group. Finally, cellular immune response was tested via cytokine (IFN-&gamma / ) assay, in which spleens of mice were excised, splenocytes were cultured and the level of IFN-&gamma / production upon FeSOD addition to the cultures was measured via ELISA. This test showed that whole-cell immunization triggered IFN-&gamma / production at significant levels while FeSOD-immunization did not / indicating the failure of alum-adsorbed FeSOD immunization in inducing cell-mediated immune response.

Bordetella bronchiseptica é um agente respiratório zoonótico comumente encontrado em diversars espécies animais domésticos como cães, gatos, coelhos, suínos, aves e equinos. As infecções em humanos ocorrem ocasionalmente, sendo descritas com maior freqüência em indivíduos imunocomprometidos, mas relatos de casos de doença em adultos saudáveis e crianças têm aumentado. O presente estudo teve como objetivos determinar o perfil de resistência antimicrobiana de cepas de B. bronchiseptica isoladas de cães, gatos, coelhos e suínos, caracterizar as cepas pela eletroforese em campo pulsado (PFGE), e comparar os resultados obtidos com os dados epidemiológicos. Foram avaliadas 145 cepas e estas apresentaram 100% de resistência a ampicilina, penicilina, espectinomicina, clindamicina, tiamulina e tilosina. Taxas de resistência superiores a 95% das cepas foram observadas frente a tilmicosina, danofloxacina e ceftiofur. Os antimicrobianos com menores taxas de resistência foram enrofloxacina (2,1%) e clortetraciclina (11 %). As cepas isoladas de coelhos apresentaram menores taxas de resistência que as de suínos e de animais de companhia. A caracterização das cepas pela PFGE permitiu a separação de acordo com as espécies de origem em diferentes pulsotipos. A caracterização do agente, principalmente no que se refere à resistência a antimicrobianos, será de grande utilidade para os veterinários no controle das infecções pelo mesmo em suínos, animais de companhia e coelhos, visto que os dados sobre este agente etiológico no Brasil são escassos / Bordefella bronchisepfica is a zoonotic respiratory agent commonly found in domestic animais as dogs, cats, rabbit, swine, birds and horses, Infections in humans occur rarely and have been described more frequently in immunocompromised individuais, but reports of cases of illness in healthy adults and children have increased. This study aims to characterize the resistance profile of B. bronchiseptica strains isolated from dogs, cats, rabbits and pigs and evaluate the strains by pulsed field gel electrophoresis (PFGE), comparing the results with epidemiological data. From 145 strains tested 100% presented resistance to ampicillin, penicillin, spectinomycin, clindamycin, tiamulin and tylosin. Resistance rates higher than 95% were found against tilmicosin, danofloxacin and ceftiofur. The antimicrobials with lower resistance rates were enrofloxacin (2.1 %) and chlortetracycline (11 %). Strains isolated from rabbits presented low resistance rates when compared with swine and pet animais. The PFGE analysis separated the strains according specie of origin in different pulsotypes. The agent characterization, mainly in relation with antimicrobial resistance will be of great help to veterinarians in control of infections in swine, pets and rabbits, since data about this bacteria in Brazil are rare