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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
661

An investigation into the regulatory capacity of invariant natural killer T (iNKT) cells during the innate and adaptive immune response to influenza infection

McEwen-Smith, Rosanna Mary January 2014 (has links)
Influenza A virus (IAV) infection is a highly contagious respiratory disease, which can cause substantial morbidity and occasionally death. Invariant natural killer T (iNKT) cells, a subset of CD1d-restricted T lymphocytes, have been identified as important modulators of immunity, mediating both pro- and anti-inflammatory responses. We show that iNKTs play an important role for the generation of protective innate and adaptive immune responses to IAV, and enhance heterotypic immunity to influenza virus following vaccination with a novel pseudotyped virus, S-FLU, which lacks HA expression. iNKT-deficient mice (J&alpha;18<sup>-/-</sup>) showed increased susceptibility and lung pathology following IAV infection, which correlated with an exaggerated accumulation of inflammatory monocytes and neutrophils in the lung. Consistent with these findings, we demonstrated in IAV-infected CD1d<sup>-/-</sup>:CD1d<sup>&plus;/&plus;</sup> mixed bone marrow chimeric mice, that the lack of CD1d expression on myeloid cells purified from the lungs of IAV-infected mice significantly increased expression of genes linked to cell activation, survival and polarisation between pro- and antiinflammatory responses. We extended these results by examining the role of chemokine signalling during IAV infection, and identified a novel role for fractalkine (CX3CL1) and its receptor (CX3CR1) in innate immune cell recruitment. The use of CX3CR1-iNKT cell double knockout mice revealed that, although upregulated in J&alpha;18<sup>-/-</sup> mice, CX3CR1-CX3CL1 signalling is not required for cell migration during exacerbated IAV-responses. Finally, we showed that iNKT-deficient mice displayed reduced longevity of peripheral IAVspecific CD8<sup>&plus;</sup> T cells following S-FLU vaccination, compared with wild-type mice. S-FLU vaccination protected mice following 5 day heterotypic challenge, however vaccinated mice exhibited reduced viral clearance, and importantly a significant reduction in IAV specific memory T cell response, suggesting a possible role of iNKT cells during T cell priming in modulating the lifespan of antigen-specific T cell responses. Although additional experiments are warranted, these results suggest that harnessing iNKT cells should be considered to modulate the innate and adaptive immune response to optimise heterotypic vaccine design and for therapeutic intervention against acute influenza infection.
662

Beyond avian influenza : policy considerations for the implementation of a 'one health' approach in developing countries

Okello, Anna Louise January 2013 (has links)
The global One Health movement has become firmly entrenched in both political and scientific discourse pertaining to emerging infectious diseases in the past decade. Since the discovery of the H5N1 strain of Highly Pathogenic Avian Influenza in Hong Kong in 1997, the promotion of more holistic programmes for the control of emerging infectious disease has garnered “unprecedented support” in terms of donor funding and political mobilisation (Scoones 2010). Advocates of One Health argue that intersectoral approaches promoting better communication between the veterinary, medical and environmental disciplines at all levels of governance make not only sound economic sense, they are fundamental to the “new approach” required to address the growing disease threats of the 21st century. However, despite international endorsement of the One Health rhetoric, there is growing pressure to now “turn the rhetoric into reality” (Okello et al 2011). Using a multiple, embedded case study methodology, this thesis seeks to examine questions surrounding the practical implementation of One Health interventions, particularly in developing countries which experience limited resources and competing health priorities. Through examining the livestock and public health policy processes at both local and national levels in Uganda and Nigeria, I attempt to identify whether policy spaces exist for the formal inclusion of One Health approaches in future policy decisions. Furthermore, by scrutinising the current internationally dominant One Health narratives in light of global health governance perspectives and the emerging One Health Global Network, I question whether One Health can be better “packaged” to include endemic diseases and a more focussed sustainable livelihoods approach; arguably inciting greater motivation for developing countries to truly participate. Data from my three empirical chapters are presented in the context of three overriding “One Health propositions” for consideration; by questioning “whose world, whose health”, I aim to delve further into the issues of not whether, but how this “new health paradigm” can be operationalised, and how to address the potential gaps which may ultimately prevent One Health from becoming a truly global phenomenon.
663

Design, synthesis, and anti-influenza activity of substituted quercetins and progress towards the synthesis of mini graphenes like hexa-peri-benzocoronene cyclophane

Thapa, Mahendra January 1900 (has links)
Doctor of Philosophy / Department of Chemistry / Duy H. Hua / The first chapter of the thesis involves the design, synthesis, and anti-influenza activity of quercetin derivatives. Influenza viruses are important pathogens that cause respiratory infections in humans and animals. In addition to vaccination, antiviral drugs against influenza virus play a significant role in controlling viral infections by reducing disease progression and virus transmission. Plant derived polyphenols are associated with antioxidant activity, anti-carcinogenic, and cardio- and neuro-protective actions. Some polyphenols, such as resveratrol and epigallocatechin gallate (EGCG), showed significant anti-influenza activity in vitro. The antiviral effects of isoquercetin were greater than that of quercetin with lower IC[subscript]5[subscript]0 values and higher in vitro therapeutic index. Various phenolic esters, alkoxy and aminoalkoxy derivatives of quercetin were synthesized by functionalization of C3, C3’, and C5 hydroxyl groups. Antiviral activities of these synthesized compounds were tested against influenza virus (porcine H1N1 strain). Quercetin-3-gallate which is structurally similar to EGCG showed greater antiviral activity among the synthesized compounds. Its antiviral activity was comparable to that of EGCG with better in vitro therapeutic index. Second chapter in the thesis involves the progress towards the synthesis of mini graphenes like hexa-peri-benzocoronene cyclophane (HBCC). Bilayered graphenes are highly conducting materials with potential application in electronic devices and in lithium ion batteries. Despite great potential, bilayer graphenes with defined distance between the two layers have not been achieved through chemical synthesis. Chemical synthesis of hexa-peri-benzocorenene cyclophane (HBCC) from commercially available p-xylene was carried out. Final product, presumably compound 90 (the structure has not been completely characterized), is insoluble in all tested solvents including aqueous acids and organic solvents such as DMSO, DMF, benzene, 1,2-dichlorobenzene, dichloromethane, THF, hexanes and diethyl ether. The insoluble nature of the final product restricted the analysis to UV-visible spectroscopy. Synthesis of soluble analog incorporating the long chain ether groups is being investigated in Dr. Hua’s laboratory.
664

Predicción del costo económico de un brote de influenza aviar altamente patógena en las principales regiones productoras de Chile

Gumucio Palma, Tomás Antonio January 2010 (has links)
Memoria para optar al Título Profesional de Médico Veterinario / La enfermedades exóticas de un país son un peligro latente, el cual puede perjudicar de manera importante sanitariamente y económicamente un país. Es muy difícil poder estimar el impacto que tiene una enfermedad la cual nunca ha estado en un territorio. A fin de conocer la situación que se puede dar frente a la introducción de un agente externo, muchos países trabajan simulaciones matemáticas y computacionales con el propósito de obtener más información sobre las condiciones epidemiológicas, sus impactos económicos e incluso proponen medidas que permitan aminorar los riesgos y reducir las pérdidas frente a un posible brote real. Al crecer la industria, los parámetros antes estimados van quedando obsoletos, por lo que es necesario re-estimarlos, con el fin de prepararse frente a nuevas apariciones de brotes de enfermedades. Por este motivo hemos decidido estimar el costo de un nuevo brote de influenza aviar altamente patógena en Chile, principalmente enfocado a la industria avícola. Esta re-evaluación de costos se realizó mediante simulación de un brote de influenza aviar altamente patógena utilizando programas computacionales. Optamos por utilizar el programa Modelo de Diseminación de Enfermedades Animales de Norte América (NAADSM por sus siglas en Inglés) que fue desarrollado con el objetivo primario de producir una aplicación de modelado comprensiva y fácil de usar para la evaluación de medidas de control para enfermedades animales infecciosas extranjeras, planificación para estado de preparación, y ejercicios de entrenamiento. Se optó por el uso de este programa debido a la facilidad en el ingreso de datos, los cuales se pueden ir adaptando a medida que la industria se vaya desarrollando. En nuestro trabajo se simuló el brote con el ingreso del virus de la influenza aviar altamente patógena a través de aves migratorias que lleguen a las Zonas de Riesgo Primario dando inicio a un brote. En las simulaciones realizadas se estimó el costo directo de un brote de influenza aviar entre $208 millones de pesos (U$440.000 dólares) hasta $10.824 millones de pesos (U$21,68 millones de dólares) que fue el caso de una simulación en la cual se infectó un plantel de reproductoras broiler el cual infectó 22 planteles de engorda broiler
665

Die Rolle des Transkriptionsfaktors NF-KappaB in Influenza-A-Virus infizierten Zellen / The role of the transcriptionfactor NF-kB in influenza-A-virus infected cells

Wurzer, Walter January 2003 (has links) (PDF)
Die Aktivierung von Transkriptionsfaktors NF-kB ist ein Charakteristikum viraler Infektionen, einschließlich der Infektion durch Influenza-A-Viren (Hiscott J. et al., 2001). Da die Expression vieler proinflammatorischer und antiviraler Zytokine, wie IFNb oder TNF-a durch NF-kB kontrolliert wird, hat sich ein Konzept entwickelt, welches besagt, dass NF-kB und sein übergeordneter Aktivator IKK wichtige Bestandteile der angeborenen, antiviralen Immunität im Kontext einer Infektion mit RNA-Viren sind (Chu WM. Et al., 1999). Im Gegensatz zu dieser weithin akzeptierten Ansicht, wurde in der hier vorliegenden Arbeit gezeigt, dass die Aktivierung von NF-kB für eine effiziente Influenzareplikation von großer Wichtigkeit ist. Auf einer molekularen Ebene wurde dies durch die NF-kB-abhängige virale Aktivierung des proapoptotischen Faktors TRAIL gezeigt, welcher die Virusvermehrung sowohl auto- als auch parakrin erhöht. Somit kann man sagen, dass NF-kB im Kontext einer Influenza-A-Virusinfektion sowohl proapoptotisch als auch proviral wirkt. Die Induktion der Apoptose ist ein weiteres, charakteristisches Merkmal, das man im Zusammenhang mit Virusinfektionen beobachten kann. Da die Rolle der Apoptose während einer Influenza-A-Virusinfektion noch unklar war, wurde diese Frage adressiert. Dabei wurde versucht mit einem wichtigen, virus-induzierten Apoptose-Effektor, nämlich Kaspase-3 zu interferieren. Überraschenderweise wurde die Influenzavermehrung in Anwesenheit eines Kaspase-3-Inhibitors stark negativ beeinflusst. Im Einklang mit diesem Befund konnte gezeigt werden, dass die Virustiter in Zellen, in denen XIAP überexprimiert wurde, rückläufig waren. Gegengleich führte Überexpression von Prokaspase-3 zu einem Titeranstieg. Mechanistisch scheint der Blockade der Virusvermehrung eine Retention der viralen RNP-Komplexe im Zellkern zu Grunde zu liegen, die die Bildung von reifen Viruspartikel verhindert. Die Erklärung dürfte in der Aktivität von Kaspase-3 zu finden sein, die an dem Abbau von Kernporenkomplexproteinen in apoptotischen Zellen beteiligt ist und was in Folge die freie Diffusion viraler RNPs ermöglichen dürfte. Abschließend entwickelte sich aufgrund der vorliegenden Arbeit eine neue Hypothese über die Rolle des IKK-NF-kB-Signalweges, seinen Einfluss auf die Apoptoseregulation in Influenza-infizierten Zellen und der Auswirkung auf das Virus. / Activation of the transcription factor NF-kB is a hallmark of infections by viral pathogens including influenza-A-viruses (Hiscott J. et al., 2001). Since gene expression of many proinflammatory and antiviral cytokines, such as IFNb of TNF-a is controlled by NF-kB the concept emerged that NF-kB and its upstream regulator IKK are essential components of the innate antiviral immune response to infections with RNA viruses (Chu WM. et al., 1999). In contrast to this common view this work presents data that for efficient influenza virus production NF-kB activity is required. On a molecular level this is due to NF-kB-dependent viral induction of the proapoptotic factor TRAIL which enhances virus propagation in an auto- and parakrine fashion. Thus, NF-kB acts both proapoptotic and proviral in the context of an influenza virus infection. Induction of apoptosis is a hallmark observed upon infection with many viral pathogens, including influenza-A-virus. Since the consequences of apoptosis induction for the outcome of an influenza virus infection are not clear, we have addressed this issue by interfering with the function of a major virus-induced apoptosis effector, caspase-3. Surprisingly, influenza virus propagation was strongly impaired in the presence of a caspase-3 inhibitor in cultures cells. Consistent with these findings, virus yields are reduced in cells expressing XIAP and enhanced when procaspase-3 is overexpressed. Mechanistically, the block in virus propagation appears to be due to retention of the viral RNP complexes in the nucleus preventing formation of progeny virus particles. An explanation might given by an effect of caspase-3, which is involved in cleavage of protein of the nuclear pore complex in cells undergoing apoptosis, which results in fusion of the pores and might thus allow free diffusion of viral RNA complexes. Finally, this work presented here led to a new hypothesis concerning the role of the IKK-NF-kB-pathway, its influence on the regulation of apoptosis in influenza infected cells and the outcome for the virus.
666

Imunogenicidade e segurança da vacina contra influenza A H1N1/2009 em pacientes com doenças reumáticas em uso de terapia anti-TNF alfa / Immunogenicity and safety of influenza A H1N1/2009 vaccine in rheumatic diseases patients under anti-TNF therapy

Silva, Ivan Leonardo Avelino França e 05 December 2014 (has links)
\\OBJETIVOS: Avaliar a imunogenicidade e a segurança a curto prazo da vacina H1N1 pandêmica em pacientes com artrite reumatóide (AR) e espondiloartrites [ESa - artrite psoriática (AP) e espondilite anquilosante (EA)] recebendo classes distintas de terapia anti-TNF, assim como comparação com pacientes que receberam drogas modificadoras de doenças reumáticas (DMARDs) e controles saudáveis. MÉTODOS: Cento e vinte pacientes (AR, n=41; EA, n=57 e artrite psoriática - AP, n=22) em uso de agentes anti-TNF (monoclonal, n=94 e receptor solúvel, n=26) foram comparados com 116 pacientes com artrite inflamatórias em uso de DMARDs e 117 controles saudáveis. Soroproteção (SP), soroconversão (SC), médias geométricas dos títulos (MGTs), fator de aumento (FI) das MGT e eventos adversos foram avaliados 21 dias após a vacinação. RESULTADOS: Após a imunização, as taxas de SC (58,2% vs 74,3%, p=0,017) foram significativamente menores nos pacientes com espondiloartrites que receberam a terapia anti-TNF, enquanto nenhuma diferença foi observada em pacientes com AR que recebem esta terapia, em comparação com controles saudáveis (p=0,067). Pacientes com espondiloartrites que receberam anticorpos monoclonais (infliximabe/adalimumabe) tiveram uma taxa de SC significativamente menor em comparação com controles saudáveis (51,6% vs. 74,3%, p=0,002) ou para aqueles em uso de DMARDs (51,6% vs. 74,7%, p=0,005), por sua vez não houve diferença para pacientes em uso de etanercepte (86,7% vs. 74,3%, p=0,091). Uma análise dos pacientes com espondiloartrites que apresentaram SC e os que não apresentaram SC revelou que o primeiro grupo teve maior média de idade (p=0,003), maior frequência de anti-TNF (p=0,031) e anticorpos monoclonais (p=0,001), e uma menor frequência de metotrexate (p=0,028). Na regressão logística multivariada, apenas a idade avançada (p=0,015) e tratamento anticorpos monoclonais (p=0,023) permaneceram fatores importantes para a não SC em pacientes com espondiloartrites. CONCLUSÕES: Este estudo mostrou um padrão distinto da resposta imune à vacina contra a gripe pandêmica em pacientes com artrite inflamatória que receberam agentes anti-TNF, com uma imunogenicidade reduzida apenas em pacientes com espondiloartrites usando anticorpos monoclonais / OBJECTIVES: To evaluate the immunogenicity of the anti-influenza A H1N1/2009 vaccine in rheumatoid arthritis (RA) and spondyloarthritis patients receiving distinct classes of anti-TNF agents compared with patients receiving DMARDs and healthy controls. METHODS: One hundred and twenty patients (RA, n=41; ankylosing spondylitis - AS, n=57 and psoriatic arthritis - PsA, n=22) under anti-TNF agents (monoclonal, n=94 and soluble receptor, n=26) were compared to 116 inflammatory arthritis patients under DMARDs and 117 healthy controls. Seroprotection (SP), seroconversion (SC), geometric mean titre (GMT), factor increase (FI) in GMT and adverse events were evaluated 21 days after vaccination. RESULTS: After immunisation, SC rates (58.2% vs. 74.3%, p=0.017) were significantly lower in spondyloarthritis patients receiving anti-TNF therapy, whereas no difference was observed in RA patients receiving this therapy compared to healthy controls (p=0.067). Spondyloarthritis patients receiving monoclonal antibodies (infliximab/adalimumab) had a significantly lower seroconversion rate compared to healthy controls (51.6% vs. 74.3%, p=0.002) or to those under DMARDs (51.6% vs. 74.7%, p=0.005), whereas no difference was observed for patients under etanercept (86.7% vs. 74.3%, p=0.091). Further analysis of non-seroconverting and seronconverting spondyloarthritis patients revealed that the former group had a higher mean age (p=0.003), a higher frequency of anti-TNF (p=0.031) and monoclonal antibodies (p=0.001), and a lower frequency of methotrexate (p=0.028). In multivariate logistic regression, only older age (p=0.015) and monoclonal antibodies treatment (p=0.023) remained significant factors for nonseroconversion in spondyloarthritis patients. CONCLUSIONS: This study revealed a distinct disease pattern of immune response to the pandemic influenza vaccine in inflammatory arthritis patients receiving anti-TNF agents, illustrated by a reduced immunogenicity solely in spondyloarthritis patients using monoclonal antibodies
667

Avaliação do perfil dos linfócitos B de pacientes com Imunodeficiência Comun Variável antes a após administração de antígenos protéicos e polissacarídicos / Evaluation of B lymphocyte profile of Common Variable Immunodeficiency patients before and after immunization with protein and polysaccharide antigens

Baldassin, Maíra Pedreschi Marques 10 October 2014 (has links)
Introdução: A Imunodeficiência Comum Variável (ICV) faz parte de um grupo de imunodeficiências primárias na qual os pacientes apresentam defeitos na maturação e diferenciação dos linfócitos B (LB), resultando em distúrbios funcionais além de alterações na distribuição de seus subtipos. Consequentemente, estes pacientes apresentam hipogamaglobulinemia, susceptibilidade a infecções e ausência de produção de anticorpos a antígenos específicos. Na tentativa de reduzir os episódios de infecções recorrentes, alguns trabalhos têm recomendado a vacinação com patógenos mortos ou subunidades e em trabalho anterior demonstramos a eficácia clínica da vacinação de pacientes com ICV, porém, a experiência com a administração de vacinas em imunocomprometidos é limitada. Objetivos: Avaliar a cinética da distribuição das subpopulações de linfócitos B antes e após a vacinação com antígenos proteicos e polissacarídicos em pacientes com ICV acompanhados no Ambulatório de Imunodeficiências Primárias do Hospital das Clínicas, FMUSP, além da produção de anticorpos específicos aos antígenos vacinais. Pacientes e Métodos: Um grupo de 35 pacientes com ICV e 16 controles foram vacinados contra Influenza, H1N1 e S. pneumoniae. Após as coletas nos tempos pré e pós 1, 3 e 6 meses foram realizados a separação de PBMC e cultura de linfócitos com lisado viral e hemaglutinina de Influenza, além da citometria de fluxo para identificação das subpopulações de LB naive, zona marginal (MZB), memória com troca de isotipo (SMB) e plasmoblastos (PBL). Foram dosados os anticorpos específicos e no grupo dos pacientes foi aplicado um score de sintomas antes e após a imunização. Resultados: Apesar da redução significativa na pontuação do score de sintomas, a maioria dos pacientes não produziu anticorpos específicos para Influenza, H1N1 e S. pneumoniae. A análise da cinética das subpopulações de LB revelou que em indivíduos saudáveis, a resposta contra Influenza apresentou duração de 6 meses, observada por meio da redução da subpopulação naive e aumento gradual da frequência de SMB a partir do primeiro mês. Observamos também redução da população de memória por volta do 3º mês, com aumento da população de PBL que permaneceu elevada até o 6º mês. Por outro lado, a despeito de os pacientes apresentarem aumento de SMB no primeiro mês após a vacinação, sua frequência foi inferior ao observado nos controles, decaindo ao terceiro mês. A população de PBL apresentou aumento precoce no primeiro mês após a vacinação, também muito menor do que observado nos controles, não sendo mantido no terceiro mês. Ainda, observamos uma correlação entre o aumento da expressão destas duas subpopulações no primeiro mês. Apenas a população de MZB apresentou aumento significativo no terceiro mês nos pacientes quando comparados aos controles. Ao dividirmos os pacientes de acordo com a expressão de SMB e PBL após 1 mês da administração das vacinas, observamos que os pacientes que apresentaram aumento na expressão de células B de memória foram os que exibiram uma melhora clínica mais expressiva, soroconverteram e desenvolveram soroproteção para H1N1.Conclusões: Apesar de não apresentarem eficaz diferenciação em células de memória e efetoras, resultando na resposta precoce e de curta duração, observamos que os pacientes foram capazes de reconhecer e responder às vacinas. Além disso, a elevada expressão de MZB no terceiro mês após a vacinação pode sugerir a atuação desta subpopulação na apresentação para os LT. Estes achados reforçam a necessidade de uma melhor compreensão da ativação do sistema imune em pacientes com ICV, para uma adequada subdivisão de acordo com o perfil de resposta após a vacinação / Introduction: Common Variable Immunodeficiency (CVID) is a primary antibody deficiency characterized by defects in B lymphocyte maturation, resulting in disturbed differentiation, distribution and functional variations on its subtypes. As a result , CVID patients have hypogammaglobulinemia and poor antibody response to specific antigens with increased susceptibility to infections. In an effort to minimize the recurrent episodes of infections, some studies have recommended immunization with inactivated pathogens or subunits and in a former study we have shown the clinical improvement determined by immunization in CVID patients, but the experience with vaccines\' administration to immunodeficient patients is limited. Objectives: To evaluate the changes in distribution of B cell subtypes before and after vaccination of CVID patients followed at the Division of Clinical Immunology and Allergy of University of São Paulo Medical School with protein and polysaccharide antigens, as well as specific antibody production . Methods: A group of 35 CVID patients and 16 controls were vaccinated against Influenza, H1N1 and S. pneumoniae vaccines. Blood samples were collected before and 1, 3 and 6 months post vaccination. PBMCs were stimulated with Influenza viral lysate and hemagglutinin peptide. Flow cytometry was performed to identify naïve B cells, marginal zone (MZB), switched memory B cells (SMB) and plasmablasts (PBL). Specific antibody production was measured and a symptoms score was applied for clinical evaluation before and after immunization. Results: In spite of the significant reduction in symptoms score after vaccination, most patients didn\'t produce specific antibodies to Influenza, H1N1 and S. pneumoniae. The analyzes of B cell subtypes changes in healthy individuals upon in vitro Influenza stimulation showed that the response endured up to 6 months post immunization. We observed a reduction in naïve B cell frequency while gradual increase in SMB frequency occurred already at 1 month after vaccination. Moreover, as the memory cell population declined, PBL population increased at the third month post vaccination until the sixth month. Although patients had an increase of SMB on the first month after vaccination, it was lower than that observed in controls, decreasing by the third month post vaccination. Plasmablast frequency had an early increase on the first month, also much lower than the observed in controls decreasing by the third month. In addition, we observed a correlation between the increased expression of SMB and PBL on the first month post vaccination. In patients, only MZB subtype presented a significant increase on the third month when compared to controls. We divided the patients according SMB and PBL expression after 1 month post vaccination and we observed that patients who were able to produce memory B cells showed a better clinical improvement, developed H1N1 seroconversion and seroprotection. Conclusion: Despite the defect on differentiation into memory and effector B cells resulting in early response with lowduration, we observed that patients were able to recognize and respond to vaccines. In addition, the over expression of MZB on the third month after vaccination may suggest the role of this subpopulation as an antigen presenting cell for T cells. These findings reinforce the need of a better understanding of immune system activation and response in CVID patients to propose a division according to vaccine (antigen) responders and non responders
668

Avaliação do perfil de subpopulações de linfócitos T de memória em pacientes com ICV submetidos à vacinação contra influenza / Evaluation of T cell subpopulations\' profile common variable immunodeficiency patients submitted to influenza vaccination

Marinho, Ana Karolina Barreto Berselli 28 March 2019 (has links)
Introdução: O vírus da influenza causa doença generalizada e pode ser fatal. A vacinação diminuiu a morbimortalidade. A Imunodeficiência Comum Variável (ICV) é uma imunodeficiência primária caracterizada por defeitos na maturação e diferenciação dos linfócitos B (LB) resultando em hipogamaglobulinemia, ausência de resposta aos antígenos específicos e infecções de repetição. A maior susceptibilidade a infecções reforça o benefício da vacinação em pacientes com imunodeficiências. O questionamento sobre a vacinação neste grupo de indivíduos se deve a eficácia, uma vez que na ICV as medidas sorológicas não se mostraram úteis como correlatos de proteção. Estudos recentes do nosso grupo observaram a melhora clínica em relação ao número de infecções de vias aéreas em pacientes com ICV após a vacinação contra influenza, porém sem produção de anticorpos específicos em níveis protetores. Objetivos: Diante das observações apontadas, este trabalho tem o objetivo de investigar o envolvimento das subpopulações de linfócitos T naive e de memória, CD4+ e CD8+, na proteção induzida pela vacina influenza em pacientes com ICV. Casuística e Métodos: Foram selecionados 16 pacientes ICV e 16 controles saudáveis. Amostras de sangue foram colhidas antes e após a administração das vacinas contra A H1N1/H3N2 e B (cepas: A/Califórnia/7/2009, A/Victoria/361/2011, B/Brisbane/60/2008). A resposta específica de células T de memória foi avaliada nas condições sem estímulo pré e pós-vacina nos períodos de 1 mês, 3 meses e 6 meses, além da realização de culturas de linfócitos com a hemaglutinina de influenza (HA) e lisado viral, nos mesmos tempos. As subpopulações de linfócitos T naive e de memória foram avaliados a partir da marcação CD3+, CD4+, CD8+, CD45RA+ e CCR7+ detectados por citometria de fluxo. Esta marcação nos permitiu identificar quatro subtipos de linfócitos: LT naive (CD45+RA+CCR7+); LT de memória efetora (TEM, CD45+RA-CCR7-); LT de memória central (TCM, CD45+RA-CCR7+) e LT de memória terminalmente diferenciado (TEMRA, CD45+RA+CCR7-). A avaliação funcional dos linfócitos T após estímulo foi realizada através da marcação intracelular de IFN-Gama e IL-2. Resultados: Este estudo demonstrou uma redução na frequência de linfócitos T CD4 +, linfócitos CD4 + TCM e CD8 + TCM em pacientes com ICV e controles saudáveis após a vacina contra influenza. Observamos uma frequência aumentada de linfócitos TEM CD4 + e CD8 + em controles saudáveis e aumento da frequência de linfócitos CD8 + TEMRA em pacientes com ICV, bem como em controles saudáveis. A vacina contra influenza foi capaz de induzir a proliferação de subpopulações de linfócitos T que pode ser caracterizada pela hipótese de diferenciação linear de células sugerida por alguns autores (naive - TCM - TEM / TEMRA). Os peptídeos de HA e o lisado viral foram capazes de estimular subpopulações de linfócitos T de memória específica em pacientes com ICV e controles saudáveis, dependendo do período e das condições dos estímulos. Os resultados mostraram que nos linfócitos T CD4+, a vacinação induziu uma resposta predominantemente IL-2+, enquanto no compartimento T CD8+ observamos uma resposta polifuncional com a produção de IL-2+ e IFN-Gama+. Conclusões: Este é o primeiro estudo a avaliar as subpopulações de linfócitos T de memória em pacientes com DCV vacinados contra Influenza A (H3N2) / B e Influenza A H1N1. Nossos resultados mostraram mudanças no padrão de distribuição das subpopulações de linfócitos T naive, TCM, TEM e TEMRA e na produção de IL-2+ e IFN-Gama+ após a vacinação contra influenza, dados que sugerem e possivelmente justificam a resposta clínica e celular protetora observada em pacientes com ICV / Introduction: Influenza viruses infect humans causing widespread, sometimes fatal, disease. Common Variable Immunodeficiency (CVID) is a primary immunodeficiency characterized by defects in B lymphocyte maturation and differentiation resulting in hypogammaglobulinemia, failure to produce specific antigens and recurrent infections. The increased susceptibility to infections reinforces the benefit of vaccination in patients with immunodeficiencies. The major discussion regarding vaccination of CVID patients is the efficacy once these patients do not produce antibodies which are used as correlates of protection. Recent studies from our group showed reduced respiratory infection rates in influenza vaccinated CVID patients demonstrating a clinical response however with no production of specific antibodies in protective levels. Objective: Considering the above observations, this study has the objective of investigating the involvement of naïve and memory T lymphocytes subpopulations, CD4+ and CD8+, in the protection of influenza vaccination CVID in patients. Patients and Methods: Sixteen CVID patients and 16 healthy controls were selected for this study. Blood samples collected before and after administration of the H1N1 / H3N2 and B vaccines (strains: A / California / 7/2009, A / Victoria / 361/2011 B / Brisbane / 60/2008). Specific memory T cell response was evaluated pre and post vaccination with influenza (1 month, 3 months and 6 months). Besides characterization of lymphocyte subpopulations in PBMCs, cell culture with an influenza hemagglutinin (HA) and viral lysate were also realized. T lymphocytes subpopulations characterized by CD3+, CD4+, CD8+, CD45RA+ and CCR7+ were identified by flow cytometry. These antibodies permitted to identify four lymphocyte subtypes: naïve T cells (CD45RA+CCR7+); effective memory T cells (TEM, CD45RA-CCR7-); Central memory (TCM, CD45RACCR7+) and terminally differentiated memory T (TEMRA, CD45RA+CCR7-). Functional evaluation of lymphocytes was performed through intracellular labelling of IFN-Gama and IL-2. Results: This study showed the reductions of naïve CD4+ T cells, CD4+TCM and CD8+TCM cells in CVID patients and healthy controls after influenza vaccine. We observed an increased frequency of CD4+TEM and CD8+TEM lymphocytes in healthy controls, and increased frequency of CD8+TEMRA lymphocytes in CVID patients and healthy controls. Influenza vaccine was able to induce the proliferation of T lymphocyte subpopulations that can characterize the linear cell differentiation suggested by the authors (Naïve - TCM - TEM / TEMRA). Regarding cytokine production, there was an increase in IL-2+ production by CD4+T and CD8+T cells and an increase of IFN-Gama+ by CD8+T cells in CVID and control patients, indicating a polyfunctional cytokine response. Conclusions: To our knowledge, this is the first study that evaluated memory T lymphocyte subpopulations of CVID patients vaccinated against Influenza A (H3N2) / B and Influenza A H1N1. We show changes in the pattern of T lymphocyte subpopulations: naïve, TCM, TEM and TEMRA and IL-2+ and IFN-Gama+ production after influenza vaccination that may suggest and possibly explain the protective cellular and clinical response observed in CVID patients
669

The stability of host-pathogen multi-strain models

Hawkins, Susan January 2017 (has links)
Previous multi-strain mathematical models have elucidated that the degree of cross-protective responses between similar strains, acting as a form of immune selection, generates different behavioural states of the pathogen population. This thesis explores these multi-strain dynamic states, to examine their robustness and stability in the face of pathogenic intrinsic phenotypic variation, and the extrinsic force of immune selection. This is achieved in two main ways: Chapter 2 introduces phenotypic variation in pathogen transmissibility, testing the robustness of a stable pathogen population to the emergence of an introduced strain of higher transmission potential; and Chapter 3 introduces a new model with a possibility of immunity to both strain-specific and cross-strain (conserved) determinants, to investigate how heterogeneity in the specificity of a host immune response alters the pathogen population structure. A final investigation in Chapter 4 develops a method of reverse-pattern oriented modelling using a machine learning algorithm to determine which intrinsic properties of the pathogen, and their combinations, lead to particular disease-like population patterns. This research offers novel techniques to complement previous and ongoing work on multi-strain modelling, with direct applications to a range of infectious agents such as Plasmodium falciparum, influenza A, and rotavirus, but also with a wider potential for other multi-strain systems.
670

Caracterização da vacinação contra influenza em idosos residentes no município de Veranópolis, RS

Galli, Rosângela 29 November 2010 (has links)
Submitted by CARLA MARIA GOULART DE MORAES (carlagm) on 2015-04-01T19:55:37Z No. of bitstreams: 1 RosangelaGalli.pdf: 421605 bytes, checksum: 956a3aeb2b6232ca40132f7710884bcc (MD5) / Made available in DSpace on 2015-04-01T19:55:37Z (GMT). No. of bitstreams: 1 RosangelaGalli.pdf: 421605 bytes, checksum: 956a3aeb2b6232ca40132f7710884bcc (MD5) Previous issue date: 2010 / Nenhuma / O uso de vacinas para a prevenção de doenças se constitui em uma das mais importantes e bem sucedidas intervenções em saúde pública. Um crescente número de vacinas tornaram-se disponíveis para uso, e os gestores dos programas públicos de imunizações freqüentemente necessitam tomar a decisão sobre quais as vacinas que devem ser introduzidas nos programas de prevenção em nível de políticas de saúde pública. A mesma autora ainda coloca que em 1999, a vacina contra influenza (chamada também de vacina contra a gripe pelos leigos) foi introduzida no Brasil em campanhas anuais de vacinação, tendo como população alvo os indivíduos idosos. A infecção pelo vírus da influenza tem como principais complicações a insuficiência respiratória (pela própria infecção) e a infecção secundária do trato respiratório por agentes bacterianos, responsáveis por aumento de hospitalizações e mortalidade na população idosa. Os benefícios da vacinação contra influenza são reconhecidos na literatura médica, onde vários trabalhos demonstraram que a vacinação reduz a ocorrência de hospitalização e morte por infecção respiratória aguda na população idosa.

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