Introdução: O surgimento de uma nova cepa do vírus Influenza A, o H1N1, determinou uma pandemia no ano de 2009, com importante repercussão global. Esse vírus infectou principalmente adultos jovens e crianças menores de dois anos com grande aumento na morbimortalidade quando comparado com as taxas anuais decorrentes do influenza. Objetivo: Avaliar as características epidemiológicas e clínicas da infecção pelo vírus influenza A (H1N1) em crianças, a fim de agregar conhecimento para melhor abordagem em futuras pandemias. Métodos: Estudo de corte transversal com revisão dos prontuários de todas as crianças, entre zero e 16 anos, hospitalizadas com quadro gripal no Hospital de Clínicas de Porto Alegre (HCPA) em 2009. A identificação do vírus H1N1 foi feita através de Reação em Cadeia da Polimerase (PCR) em laboratório de referência. Resultados: Cento e noventa e uma crianças foram internadas com suspeita de infecção pelo H1N1, destas, 83 (43%) foram submetidos à pesquisa do vírus H1N1, sendo 28 positivos (34%) e 55 negativos (66%). Os pacientes positivos para H1N1 eram mais velhos, 27 (7-108) versus sete (3-32) meses (p=0,015), todos apresentaram febre versus 70% do outro grupo (p=0,015), chegaram ao hospital com menor saturação de hemoglobina, 80% (±20%) versus 95% (±4) (p<0,001) e precisaram de maior pressão expiratória final, dez (±3) versus cinco (±1) cm H2O (p=0,001) e de maior fração inspirada de oxigênio, um (0,65-1) versus 0,4 (0,4-1) (p=0,053) quando colocados em ventilação mecânica. Não houve diferença quanto à necessidade de internação em unidade de terapia intensiva, indicação de suporte ventilatório, tempo de internação e óbito. Conclusão: As crianças acometidas pelo H1N1 apresentaram-se mais graves, embora tenham tido desfechos semelhantes às não infectadas. / Introduction: A new Influenza virus stem, H1N1, determined a pandemic in 2009 with great global repercussions. This virus infected mainly young adults and children under two years of age with marked increase in morbimortality when compared with annual rates. Objective: To analyze epidemiological and clinical characteristics of the infection by influenza A (H1N1) virus in children, in order to improve knowledge to a better approach in future pandemics. Methods: Cross section study with review of patient records for all children, between zero and 16 years, hospitalized with flu-like disease at Hospital de Clínicas de Porto Alegre (HCPA) in 2009. Identification of H1N1 virus was done through PCR technique on reference laboratory. Results: One hundred ninety-one children were hospitalized with suspected H1N1 infection. Of these, 83 (43%) patients were tested for the H1N1 virus, 28 (34%) being positive and 55 (66%) negative. H1N1 patients were older, 27 (7-108) versus seven months old (3-32) (p=0,015), all had fever versus 70% of the other group (p=0,015), they arrived at the hospital with lower oxygen hemoglobin saturation, 80% (±20%) versus 95% (±4%) (p<0,001) and when placed in mechanical ventilation they needed greater end expiratory pressures, ten (±3) to five (±1) cm H2O (p=0,001) and inspired oxygen fraction, one (0,65-1) versus 0,4 (0,4-1) (p= 0,053) . There was no difference in terms of need for hospitalization in intensive care unit, need of ventilatory support or death. Conclusion: Children infected by H1N1 were more severely ill at arrival to the hospital, although they had similar outcomes to non-infected patients.

Introdução: O surgimento de uma nova cepa do vírus Influenza A, o H1N1, determinou uma pandemia no ano de 2009, com importante repercussão global. Esse vírus infectou principalmente adultos jovens e crianças menores de dois anos com grande aumento na morbimortalidade quando comparado com as taxas anuais decorrentes do influenza. Objetivo: Avaliar as características epidemiológicas e clínicas da infecção pelo vírus influenza A (H1N1) em crianças, a fim de agregar conhecimento para melhor abordagem em futuras pandemias. Métodos: Estudo de corte transversal com revisão dos prontuários de todas as crianças, entre zero e 16 anos, hospitalizadas com quadro gripal no Hospital de Clínicas de Porto Alegre (HCPA) em 2009. A identificação do vírus H1N1 foi feita através de Reação em Cadeia da Polimerase (PCR) em laboratório de referência. Resultados: Cento e noventa e uma crianças foram internadas com suspeita de infecção pelo H1N1, destas, 83 (43%) foram submetidos à pesquisa do vírus H1N1, sendo 28 positivos (34%) e 55 negativos (66%). Os pacientes positivos para H1N1 eram mais velhos, 27 (7-108) versus sete (3-32) meses (p=0,015), todos apresentaram febre versus 70% do outro grupo (p=0,015), chegaram ao hospital com menor saturação de hemoglobina, 80% (±20%) versus 95% (±4) (p<0,001) e precisaram de maior pressão expiratória final, dez (±3) versus cinco (±1) cm H2O (p=0,001) e de maior fração inspirada de oxigênio, um (0,65-1) versus 0,4 (0,4-1) (p=0,053) quando colocados em ventilação mecânica. Não houve diferença quanto à necessidade de internação em unidade de terapia intensiva, indicação de suporte ventilatório, tempo de internação e óbito. Conclusão: As crianças acometidas pelo H1N1 apresentaram-se mais graves, embora tenham tido desfechos semelhantes às não infectadas. / Introduction: A new Influenza virus stem, H1N1, determined a pandemic in 2009 with great global repercussions. This virus infected mainly young adults and children under two years of age with marked increase in morbimortality when compared with annual rates. Objective: To analyze epidemiological and clinical characteristics of the infection by influenza A (H1N1) virus in children, in order to improve knowledge to a better approach in future pandemics. Methods: Cross section study with review of patient records for all children, between zero and 16 years, hospitalized with flu-like disease at Hospital de Clínicas de Porto Alegre (HCPA) in 2009. Identification of H1N1 virus was done through PCR technique on reference laboratory. Results: One hundred ninety-one children were hospitalized with suspected H1N1 infection. Of these, 83 (43%) patients were tested for the H1N1 virus, 28 (34%) being positive and 55 (66%) negative. H1N1 patients were older, 27 (7-108) versus seven months old (3-32) (p=0,015), all had fever versus 70% of the other group (p=0,015), they arrived at the hospital with lower oxygen hemoglobin saturation, 80% (±20%) versus 95% (±4%) (p<0,001) and when placed in mechanical ventilation they needed greater end expiratory pressures, ten (±3) to five (±1) cm H2O (p=0,001) and inspired oxygen fraction, one (0,65-1) versus 0,4 (0,4-1) (p= 0,053) . There was no difference in terms of need for hospitalization in intensive care unit, need of ventilatory support or death. Conclusion: Children infected by H1N1 were more severely ill at arrival to the hospital, although they had similar outcomes to non-infected patients.

A influenza suína (IS) é uma doença altamente contagiosa, de curso rápido e pronta recuperação, causada pelo vírus Influenza tipo A (VIS). Os principais sinais clínicos são tosse, febre, anorexia e baixo desenvolvimento. A doença está presente em outros países e, geralmente, está associada com outros agentes infecciosos. Porém, no Brasil, a sua primeira descrição ocorreu em 2011 e foi associada ao vírus H1N1 pandêmico (pH1N1). O principal objetivo deste estudo foi caracterizar as alterações histológicas mais importantes em casos de doença respiratória suína sugestiva de IS e estudar a associação dessas alterações com os resultados de imuno-histoquímica (IHQ) anti-vírus da influenza A (VIA), anti-circovírus suíno tipo 2 (PVC2) e anti-vírus da síndrome reprodutiva e respiratória suína (PRRSV). Para tanto, foram estudadas 60 amostras de pulmões suínos selecionadas dos materiais do arquivo do Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS), de casos de doença respiratória remetidos no período de 2009 a 2010 e que apresentavam alterações histopatológicas compatíveis com pneumonia viral causada pelo VIS. Trinta e uma amostras (52%) foram provenientes do estado do Rio Grande do Sul, 14 (23%) do Paraná, 11 (18%) de Santa Catarina e quatro (7%) do Mato Grosso do Sul. A IHQ para IA confirmou a presença do agente viral em 45% das amostras analisadas. Os achados histológicos mais significativos associados à IHQ positiva para IA foram bronquiolite necrótica, atelectasia, broncopneumonia purulenta e hiperemia. Por outro lado, as alterações histológicas dos pulmões estudados mais significativamente associadas à IHQ negativa para IA foram hiperplasia dos pneumócitos tipo II, estruturas alveolares e bronquiolares similares a pólipos, hiperplasia de tecido linfoide associado a brônquios (BALT) e pleurite, que são alterações associadas a processos crônicos. Somente dois casos apresentaram marcação positiva na IHQ para PCV2 e nenhum pulmão foi positivo para PRRSV. Esses resultados sugerem que as lesões histológicas encontradas no presente estudo foram compatíveis com as causadas pelo VIS. Os casos negativos de IHQ para IA (55%) podem ser explicados pela baixa frequência do antígeno viral nos tecidos estudados. Como o curso da doença é muito rápido, o teste de IHQ é mais indicado para diagnóstico no início da infecção. Este estudo evidenciou novas alterações em amostras de pulmões de suínos com problemas respiratórios enviadas para o SPV UFRGS a partir de 2009, com ênfase para bronquiolite necrótica, e reforça a importância do estudo histopatológico dos casos de campo para auxiliar na monitoria da sanidade dos rebanhos. / Swine influenza is caused by swine influenza type A virus (SIV). It is a highly contagious disease with a rapid course and recovery. The main clinical signs are cough, fever, anorexia and poor performance. Usually, it is associated with other infectious agents in many countries; however, it has not been described yet in Brazil. The first report of pandemic H1N1 influenza A virus in Brazilian swine herd occurred in 2011. The main aim of this study was to characterize histological features in association with immunohistochemical (IHC) results for influenza A (IA), porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) from lung samples from 60 pigs with lesions suggestive of viral pneumonia and collected during the period 2009-2010 and diagnosed at the Setor de Patologia Veterinária of Universidade Federal do Rio Grande do Sul (SPV-UFRGS), Brazil. All the pigs in this study had clinical respiratory disease. Sample distribution was 31 (52%) from Rio Grande do Sul, 14 (23%) Paraná, 11 (18%) from Santa Catarina State and four (7%) from Mato Grosso do Sul State. Positive anti-IA IHC was observed in 45% of the cases and was associated with necrotizing bronchiolitis, atelectasia, purulent bronchopneumonia and hyperemia. Moreover, type II pneumocyte hyperplasia, alveolar and bronchiole polyp-like structures, BALT (bronchus-associated lymphoid tissue) hyperplasia and pleuritis were the significant features of negative samples by anti-IA IHC, which were associated with chronic lesions. Only two cases were positive to PCV2 and none to PRRSV, supports the hypothesis that SIV was the viral agent infecting swine’s lungs. Negative IHC to IA (55%) cases could be explained due to the absence of viral antigens associated with the rapid progress of SI; hence, IHC should be requested in the beginning of the infection. This work has shown how important a careful histological evaluation should be done in order to give the diagnosis. Since 2009, a new histological feature of swine pneumonia from animals with respiratory clinical sign has been observed at samples submitted to SPV-UFRGS. In addition, these results described here proved the importance of histological evaluation in swine herd health management.

Le virus influenza a (via) est responsable d'epidemies annuelles et de pandemies sporadiques. un element clef, impactant a la fois la replication du virus et les symptomes de l'hote, est la reponse immunitaire innee. le via perturbe les voies metaboliques des cellules infectees, notamment la macroautophagie. la macroautophagie, par la suite appelee simplement autophagie, est une voie du catabolisme cellulaire. l'autophagie est constitutive dans les cellules nucleees et participe au maintien de l'homeostasie cellulaire. en reponse a un stress cellulaire, l'autophagie peut etre stimulee. un grand nombre de virus perturbe l'autophagie, soit en la stimulant, soit en l'inhibant. le via induit l'autophagie mais inhibe sa phase finale, un mecanisme impliquant sa proteine de matrice 2 (m2). les impacts de cette perturbation de l'autophagie sur la replication virale et sur la reponse de la cellule hote sont encore peu compris. au cours de ma these, j'ai developpe des modeles cellulaires dans lesquels la capacite d'autophagie peut etre specifiquement restauree dans des lignees cellulaires autrement incapables d'autophagie. l'utilisation de ces modeles m'a permis de montrer que l'autophagie ne change ni l'infectiosite du virus ni si capacite de replication intracellulaire mais inhibe l'induction de l'interferon-β et des genes induits par celui-ci. j'ai mis en evidence que m2 n'inhibe la phase finale de l'autophagie que dans le cadre de l'infection et de l'activation de l'apoptose. une meilleure comprehension des perturbations de l'autophagie pourrait permettre de developper des molecules antivirales et de nouveau virus attenues induisant une plus forte reponse immunitaire. / Influenza a virus (iav) is responsible for yearly epidemics and sporadic pandemics. understanding the mechanism by which the inflammatory response is mounted and controlled is key to manage the disease. iav perturbs a variety of metabolic pathways including macroautophagy. macroautophagy, hereafter referred to as autophagy, is a catabolic pathway that is active in all nucleated cells. in stress condition, autophagic activity can be increased. a variety of viruses perturb autophagy. iav has been described to both induce autophagy and block its completion mainly through its matrix protein 2 (m2). however, the impact of such perturbation on viral replication and host cell response to infection is still unknown. i developed cellular models in which autophagy capacity can be specifically restored in cell lines that are otherwise autophagy-incompetent. using these models, i showed that autophagy does not impact iav infection and replication but inhibits interferon-β induction at early stages post infection, leading to dampened induction of interferon-stimulated genes. i showed that m2 does not prevent autophagy completion by itself but only in the context of iav in a caspase-activation dependent fashion. in summary, my thesis work, using these novel autophagy models, revealed that early autophagy induction post-iav infection inhibits ifn-β, leading to a global decrease in interferon stimulated gene expression. indeed, sustained autophagy perturbation through m2 may allow iav to limit the ifn-β response throughout its life cycle. preventing m2-mediated autophagy perturbation may allow us to develop new antiviral strategies as well as new live attenuated iav vaccines.

Objetivos. Determinar las características clínicas y demográficas de la neumonía por el virus de influenza AH1N1/2009 pandémico en un hospital de referencia de Perú. Materiales y métodos. Se realizó un estudio serie de casos en niños hospitalizados por neumonía por influenza AH1N1/2009 pandémico en un hospital de referencia. Revisamos las historias clínicas entre los meses de junio a septiembre 2009. Todos los casos tuvieron confirmación virológica. Resultados. Se encontró 74 casos de neumonía por el virus de Influenza AH1N1/2009 pandémico (NVIp), de los cuales 50 tuvieron el diagnóstico de neumonía adquirida en la comunidad viral (NACv) y 24 con neumonía nosocomial viral (NNv) de los cuales 16 requirieron ventilación mecánica. Fallecieron 12, todos ellos con antecedentes de comorbilidad. Los casos NNv presentaron asociación estadística con mortalidad. En los casos NACv, los menores de 6 años representaron 72 % (36/50). La mediana de tiempo de enfermedad fue de 5 días. Los síntomas más frecuentes fueron fiebre, tos, rinorrea. Recibieron oseltamivir el 82 %. En la radiografía de tórax el 48 % de los casos presentó infiltrado en parches y el 44 % infiltrado intersticial en la radiografía de tórax. La proteína C reactiva (PCR) mayor a 10mg/L tuvo una asociación significativa con insuficiencia respiratoria (p <0,05). Conclusiones. Encontramos casos NNv quienes tuvieron mayor mortalidad, también los que presentaron el PCR elevado y los que presentaron condición preexistente. / ObjectiveTo determine the clinical and demographic characteristics of pneumonia with influenza virus AH1N1/2009 pandemic at the National Institute of Child. Methods. Retrospective case series in children hospitalized for influenza pneumonia pandemic AH1N1/2009 in a pediatric hospital. Reviewed the medical records between the months of June to September 2009. All cases had virological confirmation, we describe the clinical characteristics and conditions of severity. Results. A total of 74 children of pneumonia with influenza virus AH1N1/2009 pandemic (NVIp), of those 50 were community acquire pneumonia viral (NACv) and 24 pneumonia nosocomial viral (NNv), 16 required mechanical ventilation. 12 died, all had preexisting factors. NN cases showed statistical association with mortality. The most frequent factors were malnutrition, respiratory infections, congenital heart disease and neurological deficits In NACv cases the children under 6 years accounted for 72% (36/50). The median disease duration was 5 days. The most frequent symptoms were fever, cough, runny nose. Received oseltamivir 82%. The chest radiograph 48% of cases showed patchy infiltrates and 44% interstitial infiltrate on chest radiograph. Protein c reactive (CRP) more than 10mg / L was significantly associated with respiratory failure (p <0.05). Conclusions. Cases of NN found who had more mortality, even those who had the highest PCR and those with preexisting condition.

Durant l’infection par le virus Influenza A (IAV), les changements physiques et immunologiques du poumon prédisposent l’hôte aux surinfections bactériennes. Les cellules T Natural Killer invariantes (iNKT) sont des lymphocytes T innés pouvant avoir des rôles bénéfiques ou délétères durant l’infection. Nos objectifs ont visé à (i) étudier le rôle naturel des cellules iNKT et (ii) à rechercher l’effet d’une activation exogène des cellules iNKT dans la surinfection bactérienne post-influenza.Lors de mon arrivée, le laboratoire venait de décrire, pour la première fois en contexte infectieux, que les cellules iNKT étaient capables de produire de l’IL-22 au cours de l’infection grippale. Cette cytokine joue un rôle majeur dans les processus de maintien et de réparation des épithéliums. L’une des causes des surinfections bactériennes post-grippales étant l’altération et/ou la perte de l’intégrité de l’épithélium pulmonaire, nous nous sommes proposés d’étudier le rôle potentiel de cette cytokine dans un modèle expérimental de surinfection bactérienne à S. pneumoniae. Nous avons ainsi pu montrer que si cette cytokine ne joue pas un rôle majeur dans la réponse anti-virale de l’hôte, l’IL-22 participe au contrôle de l’inflammation au cours de l’infection grippale et joue un rôle protecteur dans la surinfection bactérienne.Par ailleurs, l’utilisation de souris dépourvues en cellules iNKT (Jα18-/-) a permis de montrer que les cellules iNKT limitent la susceptibilité aux surinfections et réduisent le synergisme létal de la coinfection virus/bactérie. Au moment de l’infection bactérienne, les cellules iNKT des souris grippées sont incapables de produire de l’IFN-γ, cytokine dont nous avons montré le rôle essentiel dans les mécanismes de défense antibactérienne. Le défaut d’activation des cellules iNKT chez les souris surinfectées est lié à l’interleukine-10 (IL-10), cytokine immunosuppressive induite par l’infection virale, plutôt qu’à un défaut intrinsèque des cellules iNKT. L’IL-10 inhibe l’activation des cellules iNKT en réponse au pneumocoque en inhibant la production d’IL-12 par les cellules dendritiques dérivées de monocytes (MoDCs). La neutralisation de l’IL-10 restaure l’activation des cellules iNKT et augmente la résistance à la surinfection. Ainsi, les cellules iNKT ont un rôle bénéfique (en amont de la colonisation bactérienne) dans le contrôle de la surinfection bactérienne de la grippe et représentent une cible de l’immunosuppression.Nous avons par la suite étudié la possibilité que le superagoniste des cellules iNKT, l’ α-galactosylceramide (α-GalCer) puisse limiter la surinfection bactérienne. Pour cela, les souris ont été traitées par voie intranasale avec de l’α-GalCer à différents temps post-influenza, juste avant l’infection par le pneumocoque. Le traitement à jour 3, au pic de la réplication virale, limite fortement la surinfection. Cependant, l’inoculation d’α-GalCer pendant la phase aiguë du virus (jour 7) ne permet pas d’activer les cellules iNKT pulmonaires et n’a pas d’effet sur la surinfection. L’absence d’activation des cellules iNKT n’est pas intrinsèque et est associée à une disparition complète des cellules dendritiques CD103+ respiratoires (cDCs), lesquelles sont cruciales dans l’activation des cellules iNKTs. À des temps plus tardifs (jour 14), les cDCs repeuplent le poumon et l’α-GalCer promeut l’activité antibactérienne des cellules iNKT.Pris dans son ensemble, cette étude souligne le rôle des cellules iNKT dans la surinfection bactérienne de la grippe et ouvre de nouvelles voies thérapeutiques afin de limiter les surinfections bactériennes post-influenza. / XDurant l’infection par le virus Influenza A (IAV), les changements physiques et immunologiques du poumon prédisposent l’hôte aux surinfections bactériennes. Les cellules T Natural Killer invariantes (iNKT) sont des lymphocytes T innés pouvant avoir des rôles bénéfiques ou délétères durant l’infection. Nos objectifs ont visé à (i) étudier le rôle naturel des cellules iNKT et (ii) à rechercher l’effet d’une activation exogène des cellules iNKT dans la surinfection bactérienne post-influenza.Lors de mon arrivée, le laboratoire venait de décrire, pour la première fois en contexte infectieux, que les cellules iNKT étaient capables de produire de l’IL-22 au cours de l’infection grippale. Cette cytokine joue un rôle majeur dans les processus de maintien et de réparation des épithéliums. L’une desDuring the infection by the virus Influenza A ( IAV), the physical and immunological changes of the lung predispose the host to the bacterial secondary infections. The invariant cells(units) T Natural Killer iNKT ) are lymphocytes T innate being able to have beneficial or noxious roles during the infection. Our objectives aimed at i) to study the natural role of cells(units) iNKT and ii) to look for the effect of an exogenous activation of cells(units) iNKT in the bacterial secondary infection post-influenza. During my arrival, the laboratory had just described, for the first time in infectious context, that cells(units) iNKT were capable of producing of IL-22 during the flu-like infection. This cytokine plays a major role in the processes of preservation and repair of epitheliums [...]

L’empaquetage des huit segments du génome des virus influenza de type A est une des étapes clef du cycle viral. Il intervient également dans l’apparition de virus réassortants, les virus pandémiques par exemple, ce qui en fait un enjeu fondamental de la recherche actuelle.Nous avons étudié ce mécanisme au cours de deux études, la première portant sur les vaccins antigrippaux (réassortiment), la seconde visant à construire un virus vecteur (incorporation d’un segment hétérologue). Les semences vaccinales sont obtenues par co-infection d’oeufs de poule embryonnés avec deux souches virales une donneuse (souche circulante de référence) et une accepteuse (A/Puerto Rico/8/34 (H1N1) (PR8)). L'analyse de la composition génétique de treize semences vaccinales H3N2 montre que le segment PB1 de la souche donneuse est présent dans plus de 50 % des semences analysées et qu’une grande variété de réassortants,allant de 6:2 à 2:6 (PR8:H3N2), peut résulter de ces coinfections. Des expériences de compétition d'encapsidation de segments à l’aide de la génétique inverse révèlent que l'encapsidation sélective du segment PB1 dépend de son environnement génétique notamment l’origine virale des segments HA et NA. La seconde partie de mon travail de thèse a été consacrée à la construction d’un vecteur réplicatif sur la base d’un virus influenza H3 naturel sans segment NA. Aucune des constructions contenant le transgène gfp n’a été incorporée dans les particules virales, contrairement à ce qui a été décrit dans la littérature. Bien que les mécanismes moléculaires régissant l’incorporation des segments des virus influenza A demeurent très complexes, le fond génétique semble être déterminant pour ce processus. / The packaging of the eight segments corresponding to the influenza A viruses genomeis a key process of the viral replication as well as a stake of actual scientific researchesbecause it leads to reassortant viruses, e.g. pandemic viruses. We studied the two main facetsof influenza segment packaging: reassortment, during vaccine seeds production and foreignsegment incorporation for influenza vector construction. Vaccine seeds are produced bycoinfection of hens’ eggs with two viruses, a donor one (reference circulating strain) and anacceptor one (A/Puerto Rico/8/34 (H1N1) (PR8)). Analysis of internal genetic composition ofthirteen H3N2 vaccine seeds reveals that PB1 segment of H3N2 donor strain is incorporatedin more than fifty per cent of the cases. Moreover, coinfection events lead to an extremelywide range of reassortants from 6:2 to 2:6 (PR8:H3N2). Segment incorporation competitionassays performed using plasmid-based reverse genetics show that selective packaging of PB1segment is based on genetic environment, i.e. viral origin of HA and NA segments. Thesecond part of my PhD work has been devoted to replicative influenza vector based on H3virus isolated from patients without NA segment at the native stage. None of the gfptransgenic constructions containing reporter gene have been incorporated in viral particles,contrary to literature studies performed using H1N1 laboratory-adapted strains. Even ifmolecular mechanisms controlling influenza A viruses segments incorporation remain stillcomplex, genetic background seems to be an essential element which must be considered withinterest.

A influenza suína (IS) é uma doença altamente contagiosa, de curso rápido e pronta recuperação, causada pelo vírus Influenza tipo A (VIS). Os principais sinais clínicos são tosse, febre, anorexia e baixo desenvolvimento. A doença está presente em outros países e, geralmente, está associada com outros agentes infecciosos. Porém, no Brasil, a sua primeira descrição ocorreu em 2011 e foi associada ao vírus H1N1 pandêmico (pH1N1). O principal objetivo deste estudo foi caracterizar as alterações histológicas mais importantes em casos de doença respiratória suína sugestiva de IS e estudar a associação dessas alterações com os resultados de imuno-histoquímica (IHQ) anti-vírus da influenza A (VIA), anti-circovírus suíno tipo 2 (PVC2) e anti-vírus da síndrome reprodutiva e respiratória suína (PRRSV). Para tanto, foram estudadas 60 amostras de pulmões suínos selecionadas dos materiais do arquivo do Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS), de casos de doença respiratória remetidos no período de 2009 a 2010 e que apresentavam alterações histopatológicas compatíveis com pneumonia viral causada pelo VIS. Trinta e uma amostras (52%) foram provenientes do estado do Rio Grande do Sul, 14 (23%) do Paraná, 11 (18%) de Santa Catarina e quatro (7%) do Mato Grosso do Sul. A IHQ para IA confirmou a presença do agente viral em 45% das amostras analisadas. Os achados histológicos mais significativos associados à IHQ positiva para IA foram bronquiolite necrótica, atelectasia, broncopneumonia purulenta e hiperemia. Por outro lado, as alterações histológicas dos pulmões estudados mais significativamente associadas à IHQ negativa para IA foram hiperplasia dos pneumócitos tipo II, estruturas alveolares e bronquiolares similares a pólipos, hiperplasia de tecido linfoide associado a brônquios (BALT) e pleurite, que são alterações associadas a processos crônicos. Somente dois casos apresentaram marcação positiva na IHQ para PCV2 e nenhum pulmão foi positivo para PRRSV. Esses resultados sugerem que as lesões histológicas encontradas no presente estudo foram compatíveis com as causadas pelo VIS. Os casos negativos de IHQ para IA (55%) podem ser explicados pela baixa frequência do antígeno viral nos tecidos estudados. Como o curso da doença é muito rápido, o teste de IHQ é mais indicado para diagnóstico no início da infecção. Este estudo evidenciou novas alterações em amostras de pulmões de suínos com problemas respiratórios enviadas para o SPV UFRGS a partir de 2009, com ênfase para bronquiolite necrótica, e reforça a importância do estudo histopatológico dos casos de campo para auxiliar na monitoria da sanidade dos rebanhos. / Swine influenza is caused by swine influenza type A virus (SIV). It is a highly contagious disease with a rapid course and recovery. The main clinical signs are cough, fever, anorexia and poor performance. Usually, it is associated with other infectious agents in many countries; however, it has not been described yet in Brazil. The first report of pandemic H1N1 influenza A virus in Brazilian swine herd occurred in 2011. The main aim of this study was to characterize histological features in association with immunohistochemical (IHC) results for influenza A (IA), porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) from lung samples from 60 pigs with lesions suggestive of viral pneumonia and collected during the period 2009-2010 and diagnosed at the Setor de Patologia Veterinária of Universidade Federal do Rio Grande do Sul (SPV-UFRGS), Brazil. All the pigs in this study had clinical respiratory disease. Sample distribution was 31 (52%) from Rio Grande do Sul, 14 (23%) Paraná, 11 (18%) from Santa Catarina State and four (7%) from Mato Grosso do Sul State. Positive anti-IA IHC was observed in 45% of the cases and was associated with necrotizing bronchiolitis, atelectasia, purulent bronchopneumonia and hyperemia. Moreover, type II pneumocyte hyperplasia, alveolar and bronchiole polyp-like structures, BALT (bronchus-associated lymphoid tissue) hyperplasia and pleuritis were the significant features of negative samples by anti-IA IHC, which were associated with chronic lesions. Only two cases were positive to PCV2 and none to PRRSV, supports the hypothesis that SIV was the viral agent infecting swine’s lungs. Negative IHC to IA (55%) cases could be explained due to the absence of viral antigens associated with the rapid progress of SI; hence, IHC should be requested in the beginning of the infection. This work has shown how important a careful histological evaluation should be done in order to give the diagnosis. Since 2009, a new histological feature of swine pneumonia from animals with respiratory clinical sign has been observed at samples submitted to SPV-UFRGS. In addition, these results described here proved the importance of histological evaluation in swine herd health management.

Acute viral infections induce CD8 memory T cells that play an important role in the protection of the host upon re-infection with the same pathogen. These virus epitope-specific memory CD8 T cells develop complex TCR repertoires that are specific for that epitope. As individuals age virus-specific immunity appears to wane. Older people have difficulty controlling infection with common viruses such as influenza A (IAV), a RNA virus which causes recurrent infections due to a high rate of genetic mutation, and Epstein Barr virus (EBV), a DNA virus which persists in B cells for life in the 95% of people that become acutely infected. Many factors may contribute to this waning immunity including changes in virus-specific TCR repertoires. We hypothesize that epitope-specific memory CD8 TCR repertoires to these two common viruses change with increasing age and that CD8 T cell cross-reactivity may be one of the mechanisms mediating these changes. To address this hypothesis in our first study, we compared epitope-specific CD8 memory TRBV repertoires directly ex vivo for these two common human viruses. In cross-sectional and longitudinal studies of EBV seropositive, HLA-A2+, young (18-22 years), middle age (25-59 years), and older (>60 years) donors, we demonstrated that CD8 memory TCR repertoires to three immunodominant epitopes, known to have cross-reactive responses, IAV-M158-66, EBV-BM280-288, and EBV-BR109-117 co-evolve as individuals age. Cross-sectional studies showed that IAV-M1-and both EBV-specific repertoires narrowed their TRBV usage by middle-age. In fact, narrowing of EBV-BM and EBV-BR-specific TRBV usage correlated with increasing age. Although narrowing of IAV-M1-specific TRBV did not directly correlate with increasing age there was clear evidence that the TRBV usage was changing with age. The dominant TRBV19 usage appeared to become bimodal in the older age group and interestingly TRBV30 usage did directly correlate with age. For the EBV epitope-specific responses there was preferential usage of particular TRBV and changes in the hierarchy of TRBV usage in the different age groups. Longitudinal studies tracking 3 donors over 10-15 years (middle age to older) showed that there were changes in the TCR repertoire of IAV-M1, EBV-BM and -BR-specific responses over time. In two of the donors who experienced acute IAV infection there was evidence these repertoire changes may be influenced by TCR cross-reactivity, which is enhanced during acute IAV infection. The results of this first ex vivo study are consistent with our hypothesis. They suggest that virus-specific TCR repertoires change over time as an individual ages leading to narrowing of the repertoire and may co-evolve in the presence of CD8 T cell cross-reactivity. To further test our hypothesis in a second study we compared CD8 memory TRAV and TRBV repertoires to the three immunodominant epitopes IAV-M1, EBV-BM, and EBV-BR in the two extreme age groups, young donors (YSP) (18-22 years) and older donors (OSP) (>60 years) using the same donors as in the first study. Since these three epitopes are known to generate cross-reactive CD8 T cell responses and humans during their lifetime are frequently infected with both viruses at the same time these studies were also designed to more closely examine if TCR cross-reactivity could contribute to changes in TCR repertoire with increasing age. We examined the differences in both TRAV and TRBV in these two age groups by monoclonal antibody (mAb) staining and by deep sequencing and single cell sequencing in tetramer positive sorted cells from short-term cultures. Our initial studies showed that there were strong correlations in TRBV usage between short-term cultured and ex vivo antigen-specific responses; functional differences as well as differences in TRBV usage and diversity as measured by mAb staining particularly for the EBV epitope-specific responses between YSP and OSP donors. The TCR deep sequencing data also showed significant differences in TRBV usage between YSP and OSP. However, there were many more differences in TRAV and TRAJ usage than TRBV between the age groups suggesting that TRAV may play a greater role in evolution of the TCR repertoire. With increasing age, there was a preferential selection or retention of TCR for all three epitopes that have features in their CDR3a and b that increase their ease of generation, such as greater usage of convergent recombinant amino acids, and increase cross-reactive potential, such as multiple glycines. YSP and OSP differed in the patterns of TRAV/AJ and TRBV/BJ pairings and usage of dominant CDR3 motifs in all three epitope responses. Both YSP and OSP had cross-reactive responses between these 3 epitopes which were unique and differed from the cognate responses. Analyses of single cell sequencing data suggested that unique combinations of TRAV and TRBV are occurring, where one chain has features consistent with interaction with antigen one and the other chain had features consistent with interaction with antigen two. Interestingly, both the deep sequencing and single cell data show an increased tendency for the classic IAV-M1 specific clone BV19-IRSS-BJ2.7/AV27-CAGGGSQGNLIF-AJ42 to appear among the cross-reactive clones, suggesting that the dominance of this highly public clone may relate to its cross-reactivity with EBV. These results suggest that although OSP and YSP retain some of the classic TCR features for each epitope the TCR repertoire is gradually changing with age retaining TCR that are cross-reactive between these two common human viruses that we are exposed to frequently, one with recurrent infections and the other a persistent virus which frequently reactivates. These results are highly supportive our hypothesis and their importance in relation to viral immune-pathogenesis and potential novel immunotherapies will be discussed. These studies further emphasize the complexity and potential importance of human virus-specific T cell responses and TCR repertoires as people age and the need for a better understanding of TCR cross-reactivity between different viruses. For instance, at the present time these studies are highly relevant to better understanding the immune-pathogenesis observed during the COVID19 pandemic.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22348号 / 医博第4589号 / 新制||医||1042(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 小柳 義夫, 教授 中川 一路, 教授 伊藤 貴浩 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM