No description available.

No description available.

Introdução: a coqueluche é uma doença causada pela Bordetella pertussis (BP), sendo mais frequente e grave em lactentes menores de um ano de idade. Com a introdução da vacina, houve redução na incidência mundial da doença, porém nos últimos 10 anos observa-se uma recrudescência. Pode apresentar-se de forma menos característica em lactentes, especialmente antes do final do esquema vacinal para o primeiro ano de vida. O quadro clínico, nesses pacientes, pode ser semelhante ao das infecções por vírus respiratórios (VR) que são os agentes etiológicos mais frequentes nas infecções de vias aéreas, nessa faixa etária. São necessários estudos que avaliem a importância da pesquisa de VR em lactentes com suspeita clínica de coqueluche. Objetivos: em lactentes com suspeita de coqueluche: identificar as prevalências de BP, VR e codetecções; analisar e comparar as características clínicas e a evolução, segundo a etiologia identificada e analisar o impacto do diagnóstico etiológico sobre o uso de macrolídeos. Métodos: estudo de coorte prospectivo, com crianças menores de um ano de idade, hospitalizadas com suspeita clínica de coqueluche entre junho de 2014 e junho de 2016 e submetidas à pesquisa etiológica para identificação de BP (\"swab\" de nasofaringe para cultura e/ou PCR) e pesquisa de VR (aspirado de nasofaringe para imunofluorescência indireta). Dados clínicos, demográficos e evolutivos foram coletados com o preenchimento de protocolo clínico-laboratorial padronizado. Resultados: no período de estudo foram analisados 59 lactentes. Em 18 (30,5%) houve identificação de BP, em 23 (39%) de algum vírus respiratório. Em quatro (7%), houve codetecção de BP e algum VR. O vírus mais frequentemente identificado foi o VSR (73%). As características com maior sensibilidade para o diagnóstico de infecção por BP foram tosse seguida de cianose e ser filho de mãe não vacinada com dTpa. Sibilos e desconforto respiratório apresentaram alta sensibilidade para a identificação de VR. Na análise bivariada apresentaram maior chance de infecção por BP: menor idade (OR = 1,86), ausência de febre (OR = 4,9), não ser vacinado para coqueluche (OR = 4,4), leucocitose superior a 20.000/mm3 (OR = 5,4), linfocitose superior a 10.000/mm3 (OR = 4,0) e de infecção por VR: sibilos (OR = 4,33). Após o ajuste para confundidores, os maiores preditores para BP de forma independente foram: ausência de sibilos (OR =5,7) e leucocitose superior a 20.000/mm3 (OR = 5,38). O número de pacientes com codetecção não permitiu a análise comparativa de gravidade com aqueles com agente único. Em apenas um paciente o resultado da pesquisa viral positiva resultou em suspensão de macrolídeo. Conclusão: além da BP, os VR também foram etiologias frequentes nos lactentes com suspeita clínica de coqueluche, além de casos de codetecção de BP e VR. Foram identificadas características clínicas/laboratoriais sugestivas, porém não patognomônicas das etiologias identificadas o que corrobora a necessidade da pesquisa etiológica para VR, nessa situação clínica / Introduction: Pertussis is a disease caused by Bordetella pertussis (BP), being more frequent and severe in infants less than one year old. After vaccine introduction, there was a reduction in the global incidence of the disease, but in the last ten years there was a resurgence. It may present less characteristically in infants, especially before the end of the vaccine scheme for the first year of life. The clinical picture in these patients may be similar to that of respiratory virus infections (VR), which are the most frequent etiologic agents in airway infections in this age group. Studies is necessary to evaluate the importance of RV research in infants with clinical suspicion of pertussis. Objectives: In infants with suspected pertussis: identify the prevalence of BP, VR and codetections; analyze and compare the clinical characteristics and evolution according to the identified etiology and analyze the impact of the etiological diagnosis on the use of macrolides. Methods: A prospective cohort study with children under one year of age hospitalized with suspected clinical pertussis between June 2014 and June 2016 and submitted to etiological research to identify BP (nasopharynx swab for culture and/or PCR) and VR (nasopharyngeal aspirate for indirect immunofluorescence). Clinical, demographic and evolution data were collected with the completion of a standardized clinical-laboratory protocol. Results: During the study period, 59 infants were analyzed. In 18 (30.5%) there was identification of BP, in 23 (39%) of some respiratory virus. In four (7%), there was BP detection and some RV. The virus most frequently identified was RSV (73%). The characteristics with greater sensitivity for the diagnosis of BP infection were cough followed by cyanosis and the mother\'s non-vaccinated dTpa. Wheezing and respiratory distress presented high sensitivity for RV identification. In the bivariate analysis they presented a greater chance of BP infection: lower age (OR = 1.86), absence of fever (OR = 4.9), not being vaccinated for pertussis (OR = 4.4), leukocytosis higher than 20,000/mm3 (OR = 5.4), lymphocytosis greater than 10,000/mm3 (OR = 4.0) and RV infection: wheezing (OR = 4.33). After adjustment for confounders, the largest predictors for BP independently were: no wheezing (OR = 5.7) and leukocytosis higher than 20,000/mm3 (OR = 5.38). The number of patients with codetection did not allow the comparative analysis of severity with those with single agent. In only one patient, the result of positive viral research resulted in macrolide suspension. Conclusion: In addition to BP, RVs were also frequent etiologies in infants with clinical suspicion of whooping cough, as well as cases of BP and VR codetection. Clinical/laboratory characteristics suggestive, but not pathognomonic, of the identified etiologies have been identified, which corroborates the need for etiological research for RV in this clinical situation

Bordetella pertussis e B. parapertussis são agentes etiológicos da coqueluche. A IL-12 liga a imunidade inata e adaptativa. Investigamos alguns mecanismos que controlam a síntese de IL-12 em macrófagos medulares murinos (MfDM) ativados in vitro com estas duas espécies de bactérias. Demonstramos que IL-12p40 e TNF-a foram produzidos pelos MfDM ativados com qualquer uma das bactérias. A síntese de IL-12p40 foi dependente de TNF-a, MyD88 e NFkB e independente de MAPK p38 e ERK 1/2. Durante a estimulação com B. pertussis a produção de IL-12p40 foi dependente de TLR-4, mas com B. parapertussis envolveu outras vias independentes de MyD88 e TLR-4. Estas bactérias não induziram a síntese de IL-12p70, necessitando de sinais moleculares adicionais de IFN-g, que aumentou a síntese desta citocina. A produção de IL-12 p70 aumentou após o bloqueio das vias PI3K, MAPK p38 e ERK1/2 assim como após a adição exógena de PT sobre MfDM ativados com B. parapertussis. Portanto, diversas vias de sinais dependentes e independentes de TLR-4 controlam a produção de IL-12 neste modelo. / Bordetella pertussis and B. parapertussis are etiological agents of whooping cough. IL-12 links the innate and adaptive immunity. We investigated the ability of both bacteria to modulate IL-12 by in vitro activation of bone marrow derived macrophages (MfDM). We demonstrated that IL-12p40 and TNF-a were produced after stimulation of cells with either bacterium. IL-12p40 production was dependent on TNF-a, MyD88 and NFkB but independent of MAPK p38 and ERK 1/2. During B. pertussis activation the production of IL-12p40 was dependent on TLR-4, while B. parapertussis activation was MyD88 and TLR-4 independent. However, the bacteria alone did not induce IL-12p70 synthesis, requiring IFN-g as an additional signal. Evidences indicated MAPK p38, ERK1/2 and PI3K during B. pertussis and B. parapertussis activation, as well as the exogenous addition of PT to B. parapertussis activated MfDM, was critical for the up regulation of IL-12p70. This finding indicates that different TLR-4 dependent and independent signaling pathways may control the production of IL-12 in this model.

Introdução: a coqueluche é uma doença causada pela Bordetella pertussis (BP), sendo mais frequente e grave em lactentes menores de um ano de idade. Com a introdução da vacina, houve redução na incidência mundial da doença, porém nos últimos 10 anos observa-se uma recrudescência. Pode apresentar-se de forma menos característica em lactentes, especialmente antes do final do esquema vacinal para o primeiro ano de vida. O quadro clínico, nesses pacientes, pode ser semelhante ao das infecções por vírus respiratórios (VR) que são os agentes etiológicos mais frequentes nas infecções de vias aéreas, nessa faixa etária. São necessários estudos que avaliem a importância da pesquisa de VR em lactentes com suspeita clínica de coqueluche. Objetivos: em lactentes com suspeita de coqueluche: identificar as prevalências de BP, VR e codetecções; analisar e comparar as características clínicas e a evolução, segundo a etiologia identificada e analisar o impacto do diagnóstico etiológico sobre o uso de macrolídeos. Métodos: estudo de coorte prospectivo, com crianças menores de um ano de idade, hospitalizadas com suspeita clínica de coqueluche entre junho de 2014 e junho de 2016 e submetidas à pesquisa etiológica para identificação de BP (\"swab\" de nasofaringe para cultura e/ou PCR) e pesquisa de VR (aspirado de nasofaringe para imunofluorescência indireta). Dados clínicos, demográficos e evolutivos foram coletados com o preenchimento de protocolo clínico-laboratorial padronizado. Resultados: no período de estudo foram analisados 59 lactentes. Em 18 (30,5%) houve identificação de BP, em 23 (39%) de algum vírus respiratório. Em quatro (7%), houve codetecção de BP e algum VR. O vírus mais frequentemente identificado foi o VSR (73%). As características com maior sensibilidade para o diagnóstico de infecção por BP foram tosse seguida de cianose e ser filho de mãe não vacinada com dTpa. Sibilos e desconforto respiratório apresentaram alta sensibilidade para a identificação de VR. Na análise bivariada apresentaram maior chance de infecção por BP: menor idade (OR = 1,86), ausência de febre (OR = 4,9), não ser vacinado para coqueluche (OR = 4,4), leucocitose superior a 20.000/mm3 (OR = 5,4), linfocitose superior a 10.000/mm3 (OR = 4,0) e de infecção por VR: sibilos (OR = 4,33). Após o ajuste para confundidores, os maiores preditores para BP de forma independente foram: ausência de sibilos (OR =5,7) e leucocitose superior a 20.000/mm3 (OR = 5,38). O número de pacientes com codetecção não permitiu a análise comparativa de gravidade com aqueles com agente único. Em apenas um paciente o resultado da pesquisa viral positiva resultou em suspensão de macrolídeo. Conclusão: além da BP, os VR também foram etiologias frequentes nos lactentes com suspeita clínica de coqueluche, além de casos de codetecção de BP e VR. Foram identificadas características clínicas/laboratoriais sugestivas, porém não patognomônicas das etiologias identificadas o que corrobora a necessidade da pesquisa etiológica para VR, nessa situação clínica / Introduction: Pertussis is a disease caused by Bordetella pertussis (BP), being more frequent and severe in infants less than one year old. After vaccine introduction, there was a reduction in the global incidence of the disease, but in the last ten years there was a resurgence. It may present less characteristically in infants, especially before the end of the vaccine scheme for the first year of life. The clinical picture in these patients may be similar to that of respiratory virus infections (VR), which are the most frequent etiologic agents in airway infections in this age group. Studies is necessary to evaluate the importance of RV research in infants with clinical suspicion of pertussis. Objectives: In infants with suspected pertussis: identify the prevalence of BP, VR and codetections; analyze and compare the clinical characteristics and evolution according to the identified etiology and analyze the impact of the etiological diagnosis on the use of macrolides. Methods: A prospective cohort study with children under one year of age hospitalized with suspected clinical pertussis between June 2014 and June 2016 and submitted to etiological research to identify BP (nasopharynx swab for culture and/or PCR) and VR (nasopharyngeal aspirate for indirect immunofluorescence). Clinical, demographic and evolution data were collected with the completion of a standardized clinical-laboratory protocol. Results: During the study period, 59 infants were analyzed. In 18 (30.5%) there was identification of BP, in 23 (39%) of some respiratory virus. In four (7%), there was BP detection and some RV. The virus most frequently identified was RSV (73%). The characteristics with greater sensitivity for the diagnosis of BP infection were cough followed by cyanosis and the mother\'s non-vaccinated dTpa. Wheezing and respiratory distress presented high sensitivity for RV identification. In the bivariate analysis they presented a greater chance of BP infection: lower age (OR = 1.86), absence of fever (OR = 4.9), not being vaccinated for pertussis (OR = 4.4), leukocytosis higher than 20,000/mm3 (OR = 5.4), lymphocytosis greater than 10,000/mm3 (OR = 4.0) and RV infection: wheezing (OR = 4.33). After adjustment for confounders, the largest predictors for BP independently were: no wheezing (OR = 5.7) and leukocytosis higher than 20,000/mm3 (OR = 5.38). The number of patients with codetection did not allow the comparative analysis of severity with those with single agent. In only one patient, the result of positive viral research resulted in macrolide suspension. Conclusion: In addition to BP, RVs were also frequent etiologies in infants with clinical suspicion of whooping cough, as well as cases of BP and VR codetection. Clinical/laboratory characteristics suggestive, but not pathognomonic, of the identified etiologies have been identified, which corroborates the need for etiological research for RV in this clinical situation

A coqueluche é uma doença respiratória contagiosa, causada pela bactéria Bordetella pertussis. Tendo um significativo impacto epidemiológico, esta doença sofreu uma expressiva redução após o uso disseminado de vacinas pertussis. Efeitos adversos na imunização com a Vacina de células inteiras Whole cell pertussis (wP), atribuídos a presença de lipopolissacarídeos (LPS), levou ao desenvolvimento da Vacina pertussis acelular (aP). Contudo, a imunização com aP não tem demonstrada a mesma eficiência que a imunização com wP. Diante desse cenário o objetivo deste trabalho é desenvolver o processo de produção industrial de uma nova Vacina Pertussis de células inteiras com reduzida quantidade de LPS e baixa reatogenicidade, a Vacina Pertussis Low (wPlow). Para alcançar o objetivo, foram produzidos em escala industrial 25 lotes de cultivos inativados, concentrados e submetidos à extração de LPS com solvente orgânico. Para extração de LPS foram avaliadas 4 diferentes metodologias: filtração de fluxo tangencial (TFF); filtração de fluxo tangencial com lavagem com solução com solvente orgânico (TFFSW); centrifuga tubular (CT); centrifugação de fluxo contínuo de pratos (CFC). A wPlow produzida em centrifuga de bancada e a wP foram usadas para comparação. O processo de bancada resultou na redução de LPS (método Purpald) em média de 75% do conteúdo de LPS e a redução de 81% da atividade endotóxica (dosagem de LAL). Nos processos industriais, por TFF houve a redução de ≅21% do conteúdo de LPS, porém com aumento de ≅ 52% da atividade endotóxica; por TFFSW houve a redução de 46% do conteúdo de LPS e uma redução endotóxica média de ≅ 24%; por CT ocorreu à redução de ≅ 66% do conteúdo de LPS e de ≅ 73% da atividade endotóxica; com a CFC houve a redução de ≅ 92% do conteúdo de LPS e de ≅ 61% da atividade endotóxica. Os rendimentos de processo foram ≅ 83%, 61%, 37% e 63% respectivamente para os processos de TFF, TFFSW, CT e CFC. Através de microscopia eletrônica, foi possível visualizar a integridade celular após o processamento por CFC, e o principal antígeno vacinal, a toxina pertussis foi detectada na preparação, por western-blot. Quanto à imunogenicidade, anticorpos IgG anti-pertussis foram detectados por ELISA e resultados preliminares não mostraram diferença significativa de redução de colonização pulmonar de B. pertussis em camundongos imunizados com a wPlow ou wP. Diante dos resultados obtidos, podemos concluir que os processos de TFF e TFFSW não foram eficientes na remoção da atividade endotóxica da wPlow, embora tenha ocorrido a redução do LPS. Com relação aos processos utilizando centrífugas industriais, eficientes tanto na remoção do LPS e na redução da atividade endotóxica, houve, contudo, um baixo rendimento no processo com CT. A wPlow produzida por CFC foi imunogênica, indicando a eficácia potencial desta vacina e que a produção em escala industrial é um processo viável. Como parte deste trabalho, a cepa vacinal de Bordetella pertussis foi também caracterizada pelo seu sequenciamento genômico completo (genbank número CP010323). / Whooping cough is a contagious respiratory disease caused by Bordetella pertussis. In the past this infection had a high epidemiological impact, only reduced after the use of pertussis vaccine. The association of adverse events in immunization with whole cell Pertussis vaccine (wP), attributed to the presence of lipopolysaccharides (LPS), has led to the development of acellular Pertussis vaccine (aP). However, it is known that immunization with aP does not have the same efficiency as compared to immunization with wP vaccine. In this scenario, the objective of this work is to develop the industrial production process of a new whole cell pertussis vaccine with reduced amount of LPS and low reatogenicity, the whole cell Pertussis low vaccine (wPlow). To achieve this aim, we produced 25 lots of inactivated and concentrated cultures prepared on an industrial scale and subjected to LPS extraction with organic solvent. We evaluated four industrial processes to extract the LPS from the cells: tangential flow filtration (TFF), TFF with organic solvent washing (TFFSW), tubular centrifugation (CT) and continuous flow centrifugation (CFC). These methodologies were compared with wPlow produced at bench scale obtained by centrifugation and with traditional wP. The bench process resulted in the reduction of 75% of LPS content (Purpald method) and 81% reduction in endotoxic activity (LAL dosage) on average. In the industrial processes, TFF reduced ≅ 21% in LPS content, but with a ≅52% increase in endotoxic activity; by TFFSW there was a reduction of ≅ 46% of the LPS content and an average reduction of endotoxic activity of ≅24%; CT reduced ≅ 66% of LPS content and ≅ 73% of endotoxic activity; with CFC there was a reduction of ≅ 92% in LPS content and ≅1% in endotoxic activity. The process yields were ≅ 83%, 61%, 37% and 63% respectively for the TFF, TFFSW, CT and CFC processes. Through electron microscopy, it was possible to visualize cell integrity after CFC processing, and the major vaccine antigen, pertussis toxin, was detected in the preparation by western blot. As for immunogenicity, anti-pertussis IgG antibodies were detected by ELISA and preliminary results showed no differences in the B. pertussis colonization of lungs in mice immunized with wPlow or wP. We can conclude that the TFF and TFFSW processes were not efficient in removing the endotoxic activity of wPlow, although LPS reduction occurred. Although the processes using industrial centrifuges were efficacious in the removal of LPS and in the reduction of endotoxic activity, there was a low yield in the CT process. The wPlow produced by CFC was immunogenic indicating its potential as a vaccine and that this industrial scale production is a viable process. The characterization of the vaccine strain of Bordetella pertussis by complete genome sequencing was also presented here as part of this work (genbank - number CP010323).

Bordetella pertussis e B. parapertussis são agentes etiológicos da coqueluche. A IL-12 liga a imunidade inata e adaptativa. Investigamos alguns mecanismos que controlam a síntese de IL-12 em macrófagos medulares murinos (MfDM) ativados in vitro com estas duas espécies de bactérias. Demonstramos que IL-12p40 e TNF-a foram produzidos pelos MfDM ativados com qualquer uma das bactérias. A síntese de IL-12p40 foi dependente de TNF-a, MyD88 e NFkB e independente de MAPK p38 e ERK 1/2. Durante a estimulação com B. pertussis a produção de IL-12p40 foi dependente de TLR-4, mas com B. parapertussis envolveu outras vias independentes de MyD88 e TLR-4. Estas bactérias não induziram a síntese de IL-12p70, necessitando de sinais moleculares adicionais de IFN-g, que aumentou a síntese desta citocina. A produção de IL-12 p70 aumentou após o bloqueio das vias PI3K, MAPK p38 e ERK1/2 assim como após a adição exógena de PT sobre MfDM ativados com B. parapertussis. Portanto, diversas vias de sinais dependentes e independentes de TLR-4 controlam a produção de IL-12 neste modelo. / Bordetella pertussis and B. parapertussis are etiological agents of whooping cough. IL-12 links the innate and adaptive immunity. We investigated the ability of both bacteria to modulate IL-12 by in vitro activation of bone marrow derived macrophages (MfDM). We demonstrated that IL-12p40 and TNF-a were produced after stimulation of cells with either bacterium. IL-12p40 production was dependent on TNF-a, MyD88 and NFkB but independent of MAPK p38 and ERK 1/2. During B. pertussis activation the production of IL-12p40 was dependent on TLR-4, while B. parapertussis activation was MyD88 and TLR-4 independent. However, the bacteria alone did not induce IL-12p70 synthesis, requiring IFN-g as an additional signal. Evidences indicated MAPK p38, ERK1/2 and PI3K during B. pertussis and B. parapertussis activation, as well as the exogenous addition of PT to B. parapertussis activated MfDM, was critical for the up regulation of IL-12p70. This finding indicates that different TLR-4 dependent and independent signaling pathways may control the production of IL-12 in this model.

La coqueluche est une pathologie due à la bactérie Bordetella pertussis qui touche les voies respiratoires des patients infectés causant toux, leucocytose, fièvre, et dont les symptômes peuvent aller jusqu’au décès chez les individus les plus à risque (nouveau-nés et enfants immunodéprimés en particulier). Ciblée par différents programmes vaccinaux depuis de nombreuses années, cette pathologie sévit à nouveau dans de nombreux pays développés où le nombre de cas augmente fortement depuis la fin des années 2000. Cette résurgence montre la nécessité de développer de nouvelles stratégies afin de comprendre les mécanismes de l’infection par B. pertussis. Dans ce contexte, la recherche préclinique apparaît comme essentielle pour comprendre la physiopathologie de la coqueluche. De nombreux modèles animaux ont été décrits pour l’étude de la coqueluche mais aucun de ces modèles ne permet de reproduire l’ensemble du spectre des symptômes cliniques de la pathologie, notamment la toux. Cependant, au cours des dernières années un modèle d’infection par Bordetella pertussis chez le jeune babouin a été développé aux Etats-Unis et permet de reproduire la pathologie observée chez l’homme, notamment concernant la toux et la transmission. Ce modèle semble ainsi très prometteur pour l’étude de la physiopathologie de la coqueluche.Cependant, de nombreuses inconnues subsistent dans ce modèle, notamment concernant la colonisation bactérienne et les interactions entre la bactérie et l’hôte. Nous avons ainsi cherché dans cette étude à évaluer d’une part l’impact de différents facteurs comme l’âge des animaux, la dose d’infection ainsi que la voie d’exposition sur la pathologie déclarée par les babouins suite à l’infection par la souche B1917 de B. pertussis afin de pouvoir proposer un parallèle avec les données cliniques disponibles. Nous avons également développé l’utilisation de techniques d’imagerie in vivo comme l’endomicroscopie confocale couplée à la bronchoscopie afin d’étudier la localisation et la cinétique de colonisation et certaines interactions du pathogène dans le tractus respiratoire inférieur au cours de la pathologie. Cette étude nous a ainsi permis d’approfondir les connaissances de physiopathologie de la coqueluche dans ce modèle babouin et consolidera cet outil précieux pour l’évaluation des futures stratégies de prévention contre cette pathologie. / Whooping cough, or pertussis, is a respiratory disease caused by Bordetella pertussis bacterial colonization of human airways. Main symptoms are cough, leukocytosis, fever and may even be lethal for some patients (e.g. newborn infants and immuno-deficient patients). Despite a good vaccination coverage worldwide against pertussis, whooping cough cases have been re-increasing in several developed countries in the past twenty years. This resurgence points out the crucial need to develop new control strategies and to better understand pertussis pathophysiology, notably using appropriate animal models. Numerous preclinical models including mice, rats, rabbits and swine have been described for B. pertussis infection studies. However, none of these models reproduce the full spectrum of clinical pertussis symptoms, especially cough. The recent baboon model of whooping cough described in the last few years in the US appears to be a very relevant model for pertussis pathophysiology studies as these animals reproduced all clinical symptoms as observed in humans including cough.However, many aspects of bacterial colonization and interactions with the host have yet to be described in this model.We have then evaluated diverse parameters such as animal age, the inoculum dose and the exposition route on the pathology symptoms and immune responses developed by baboons following B. pertussis B1917 strain inoculation in order to draw a parallel with human clinical data. We also developed in this model in vivo imaging techniques like confocal endomicroscopy coupled with bronchoscopy in order to evaluate bacterial colonization kinetics, localization and some interactions in the lower respiratory tract of infected baboons. Then, this study brought additional data on whooping cough physiopathology in this baboon model, which will be crucial for evaluating future prevention strategies against pertussis disease

Adenylate cyclase toxin (CyaA) is a key virulence factor of Bordetella pertussis, the causative agent of whooping cough. The toxin targets primarily myeloid phagocytes expressing CD11b/CD18 (αMβ2, CR3, Mac-1) and by elevation of cytosolic cAMP levels it paralyses their macropinocytic and opsono-phagocytic functions. Here, we dissected the cAMP-regulated pathway responsible for the block of macrophage macropinocytosis and characterized the capacity of CyaA-treated macrophages to shut- down Akt (protein kinase B, PKB) signaling; that controls nitric oxide (NO) production by macrophages. By using specific activators of protein kinase A (PKA) and for the exchange protein activated by cAMP (Epac), we show that activation of the cAMP effector Epac inhibits macropinocytosis in macrophages. Moreover, upon transfection of macrophages by the constitutively active and dominant negative variants of a downstream effector of Epac, the small GTPase Rap1, inhibition or upregulation of macrophage macropinocytosis was observed, respectively. It was reported previously that the Epac/Rap1 pathway regulates activity of tyrosin phosphatase SHP-1 as well as of protein phosphatase 2 A (PP2A). We show that inhibition of both tyrosin phosphatases and PP2A interferes with CyaA-mediated block of macropinocytosis. These...

La réponse immunitaire, qu’elle soit générée suite à un contact naturel avec un agent infectieux ou après l’administration d’un vaccin, est sujette à des variations qui peuvent être dues à des facteurs environnementaux tels que les infections ou la malnutrition.Au cours de ce travail, nous avons étudié par une approche épidémiologique, l’influence des variations saisonnières et de la malnutrition sur la réponse immunitaire vis-à-vis de vaccins administrés aux enfants avant l’âge d’un an dans le cadre du Programme Elargi de Vaccination de l’Organisation Mondiale de la Santé (coqueluche, tétanos, diphtérie, tuberculose).Une étude longitudinale multidisciplinaire de terrain a été menée au nord du Sénégal, dans 5 villages de la vallée du Grand Fleuve, sur une cohorte de 410 enfants âgés de 1 à 9 ans. Des visites ont été réalisées dans l’ensemble des villages, à différents moments de l’année, englobant des périodes de saisons sèches et de saisons humides, afin de collecter des données parasitologiques, cliniques et anthropométriques, ainsi que des échantillons sérologiques. Dans le cadre de la santé publique, cette étude a permis d’apporter des données régionales sur la couverture vaccinale, la prévalence du paludisme et de l’état nutritionnel des enfants.La réponse immune à la coqueluche a été mesurée par le dosage d’anticorps dirigés contre la toxine de la coqueluche et l’hémagglutinine filamenteuse, deux antigènes de la bactérie Bordetella pertussis, l’agent principal de la coqueluche. Nos résultats concernant la réponse humorale à ces antigènes indiquent des variations du taux d’anticorps en fonction de l’âge des enfants ainsi que de leur village de résidence. La séroprévalence à B. pertussis a révélé la circulation endémique de la bactérie dans certains villages avec l’apparition d’un pic épidémique dans l’un d’entre eux. De plus, nos analyses suggèrent que la malnutrition est associée à une diminution de la réponse humorale aux antigènes de la coqueluche et que le retard de croissance influe sur la séroconversion vis-à-vis de cette infection bactérienne. Par ailleurs, le retard de croissance semble diminuer la capacité des cellules immunitaires des enfants à produire de l’interféron gamma, une cytokine clé intervenant dans la défense contre les infections, en réponse à des antigènes vaccinaux. Les conséquences à plus long terme de la malnutrition chronique infantile sur le maintien ou le développement des réponses immunes chez ces enfants lorsqu’ils seront plus âgés demeurent un point important à étudier.Mots-clés : anticorps, vaccination, coqueluche, Bordetella, malnutrition, Sénégal / Immune response, whether generated as a result of natural contact with an infectious agent or after the administration of a vaccine, is subject to changes, which may be due to environmental factors such as infections or malnutrition.In this work, we used an epidemiological approach to study the influence of seasonal variations and malnutrition on the immune response to vaccines administered to children before the age of one, in the frame of the Expanded Programme on Immunization set up by the World Health Organization (whooping cough, tetanus, diphtheria, tuberculosis).A longitudinal multidisciplinary study was conducted in northern Senegal in 5 villages of the Great River valley, on a cohort of 410 children aged 1 to 9. Visits were conducted in all villages at different times of the year, including periods of the dry season and wet season, to collect parasitological, clinical and anthropometric data, as well as serological samples. In the context of public health, this study provides regional data on immunization coverage, malaria prevalence, and nutritional status of children.