Influenza is a significant cause of morbidity and mortality worldwide. Individuals with underlying immune conditions, including the very young, are particularly vulnerable. Infection elicits lasting antibody and T cell-mediated immune responses although antibody-mediated protection is limited due to the mutagenic nature of influenza viral surface antigens. T cell responses, in contrast, target conserved viral proteins and can protect from highly disparate strains. Compared to circulating memory, non-circulating, lung tissue-resident memory T cells (TRM) generated following influenza infection mediate enhanced viral clearance and protection following challenge. Thus, vaccination strategies promoting TRM may convey enhanced protection from disease compared to those relying on circulating responses. The factors governing TRM generation, however, are unclear and whether individuals most susceptible to infection, such as the very young, generate functional TRM is not known. This body of work investigates the nature of T cell responses and TRM establishment following influenza vaccination and infection in early life and adulthood. We have identified distinct capacities of commercially available inactivated influenza virus (IIV) and live-attenuated influenza virus (LAIV) vaccines to elicit protective responses with IIV inducing strain-specific neutralizing antibodies and LAIV generating lung-localized, virus-specific TRM capable of providing heterosubtypic protection upon viral challenge. We have further found that infants generate robust primary T cell responses following influenza infection or LAIV vaccination comparable to adults. However, mice infected or vaccinated in infancy fail to efficiently generate TRM and are less protected from subsequent infection in adulthood. We have identified enhanced expression of T-bet, known to promote effector differentiation while limiting memory T cell establishment, by primary infant effectors and further demonstrate that heterozygous infants expressing reduced T-bet generate lung TRM comparable to adults. Together, these findings have implications in influenza vaccine design, highlighting differing mechanisms of protection between IIV and LAIV, establishing TRM as a correlate of vaccine-mediated protection to influenza, as well as identifying cell-intrinsic dysregulation of a transcriptional pathway early in life necessary for effective lung TRM generation.

Introdução: A vacinação contra a influenza pandêmica A/H1N1 resultou em soroproteção em mais de 85% dos indivíduos saudáveis. Entretanto, dados em pacientes com artrite reumatoide (AR) são escassos. Objetivos: O objetivo deste estudo é avaliar a imunogenicidade e a segurança em curto prazo da vacina contra influenza pandêmica A/H1N1 em pacientes com AR e a influência da atividade da doença e da medicação nesta resposta. Métodos: Trezentos e quarenta pacientes adultos com AR em seguimento e tratamento regular e 234 controles saudáveis foram examinados antes e 21 dias após receber uma dose da vacina sem adjuvante contra influenza A/California/7/2009. A atividade da doença (DAS28), o tratamento em uso e os títulos de anticorpos também foram avaliados. As taxas de soroproteção (títulos de anticorpos >= 1:40) e soroconversão (percentagem de pacientes com aumento de título de anticorpos maior ou igual a 4, se o título pré- vacinal fosse maior ou igual a 1:10; ou título pós-vacinal de pelo menos 1:40, se o título pré-vacinal era menor que 1:10), as médias geométricas dos títulos (MGT) e o fator de incremento das médias geométricas (FI-MGT) foram calculados. Os eventos adversos foram também registrados. Resultados: Os pacientes com AR e os controles tinham taxas pré-vacinais de soroproteção (10,8% vs. 11,5%) e MGT (8,0 vs. 9,3) comparáveis (p>0,05). Após a vacinação, foi observada redução significativa na resposta dos pacientes com AR versus controles (p<0,001) em todos os desfechos sorológicos: taxas de soroproteção (60,0 vs. 82,9%) e soroconversão (53,2% vs. 76,9%), MGT (57,5 vs. 122,9) e FI-MGT (7,2 vs. 13,2). A atividade de doença não prejudicou a soroproteção ou a soroconversão e se manteve estável em 97,4% dos pacientes. O metotrexato e o abatacepte foram associados à redução da resposta vacinal. A vacinação foi bem tolerada, com poucos efeitos adversos. Conclusão: Os dados confirmaram tanto a segurança em curto prazo como, diferente da maioria dos trabalhos com influenza sazonal, a redução da soroproteção em pacientes com AR, não relacionada à atividade de doença e à maioria das medicações em uso (com exceção do metotrexato e do abatacepte). A extrapolação da resposta imunológica de uma vacina para outra pode não ser possível e estratégias específicas de imunização (possivelmente em duas doses) podem ser necessárias / Background: Pandemic influenza A/H1N1 vaccination yielded seroprotection in more than 85% of healthy individuals. However, similar data are scarce in rheumatoid arthritis (RA) patients. Objectives: The objective of this study is to evaluate the immunogenicity and the short-term safety of anti- pandemic influenza A/H1N1 vaccine in RA patients, and the influence of disease activity and medication to the response. Methods: Three hundred and forty adult RA patients in regular follow-up and treatment, and 234 healthy controls were assessed before and 21 days after adjuvant-free influenza A/California/7/2009 vaccine. Disease activity (DAS28), current treatment and anti-pandemic influenza A/H1N1 antibody titres were also evaluated. Seroprotection (antibody titre >=1:40) and seroconversion (the percentage of patients with a fourfold or greater increase in antibody titre, if prevaccination titre was 1:10 or greater, or a postvaccination titre of 1:40 or greater, if prevaccination titre was less than 1:10) rates, geometric mean titres (GMT) and factor increase in geometric mean titre (FI-GMT) were calculated and adverse events registered. Results: RA patients and controls showed similar (p>0.05) prevaccination seroprotection (10.8% vs. 11.5%) and GMT (8.0 vs. 9.3). After vaccination a significant reduction (p<0.001) was observed in all endpoints in RA patients versus controls: seroprotection (60.0 vs. 82.9%; p<0.0001) and seroconversion (53.2% vs. 76.9%) rates, GMT (57.5 vs. 122.9) and FI-GMT (7.2 vs. 13.2). Disease activity did not preclude seroprotection or seroconversion and remained unchanged in 97.4% of patients. Methotrexate and abatacept were associated with reduced responses. Vaccination was well tolerated with minimal adverse events. Conclusions: The data confirmed both short-term anti-pandemic A/H1N1 vaccine safety and, different from most studies with seasonal influenza, reduced seroprotection in RA patients, unrelated to disease activity and to most medications (except methotrexate and abatacept). Extrapolation of xii immune responses from one vaccine to another may therefore not be possible and specific immunization strategies (possibly booster) may be needed

Os pacientes com doenças reumáticas crônicas exibem um risco aumentado de contrair infecções. Consequentemente, sua vacinação é indispensável. Há relatos da produção de anticorpos antifosfolípides e tromboses após infecções e vacinação nesta população, exceto em síndrome antifosfolípide (SAF) primária. O objetivo principal deste estudo foi avaliar a curto e longo prazos um painel de anticorpos antifosfolípides após a vacinação contra influenza A/H1N1 (sem adjuvante) em SAF primária e controles saudáveis. Quarenta e cinco pacientes com SAF primária e 33 controles saudáveis foram imunizados e prospectivamente avaliados antes da vacinação e 3 semanas e 6 meses após a vacinação. Os anticorpos antifosfolípides foram determinados por ensaio imunoenzimático (ELISA) e incluíram os anticorpos IgG e IgM a seguir: anticardiolipina (aCL), anti-beta2glicoproteína I (anti-beta2GPI), anti-anexina V, anti-fosfatidilserina e anti-protrombina. O anticorpo anti-Sm foi igualmente determinado por ELISA e o anti-DNA dupla hélice, por imunofluorescência indireta. Avaliamos clinicamente à ocorrência de tromboses arterial e venosa. A frequência pré-vacinação de pelo menos um anticorpo antifosfolípide foi significativamente maior nos pacientes com SAF primária comparados aos controles (58% vs 24%, p = 0,0052). A frequência global de anticorpos antifosfolípides pré-vacinação e 03 semanas e 06 meses após a vacinação permaneceu inalterada tanto em pacientes (p = 0,89) como em controles (p = 0,83). A frequência de cada anticorpo específico nos dois grupos permaneceu estável nas três avaliações (p > 0,05). A frequência de cada anticorpo mantevese invariável nos pacientes tratados com cloroquina (p > 0,05). Em 3 semanas, 2 pacientes com SAF primária deselvolveram um anticorpo antifosfolípide novo porém transitório (aCL IgG e IgM), enquanto que em 6 meses novos anticorpos foram observados em 6 pacientes e nenhum apresentou altos títulos. Anti-Sm e anti-DNA dupla hélice foram negativos e nenhuma nova trombose arterial ou venosa foi observada durante o estudo. Este foi o primeiro estudo a demonstrar que a vacina contra influenza pandêmica em pacientes com SAF primária não induz tromboses e uma produção significante de anticorpos antifosfolípides a curto e longo prazos. (ClinicalTrials.gov, #NCT01151644). / Chronic rheumatic disease patients exhibit an increased risk for infections. Therefore, vaccination is imperative. Antiphospholipid antibodies (aPL) and thrombosis triggering after infections and vaccination in this population were reported, except for primary antiphospholipd syndrome (PAPS). Study\'s main objective was short and long-term evaluation of a panel of antiphospholipid autoantibodies following pandemic influenza A/H1N1 non-adjuvant vaccine in primary antiphospholipid syndrome patients and healthy controls. Forty-five PAPS and 33 healthy controls were immunized with A/H1N1 pandemic influenza vaccine. They were prospectively assessed at pre-vaccination, 3 weeks and 6 months after vaccination. aPL autoantibodies were determined by an enzyme-linked immunosorbent assay (ELISA) and included IgG/IgM: anticardiolipin (aCL), anti-beta2GPI; anti-annexin V, anti-phosphatidyl serine and antiprothrombin antibodies. Anti-Sm was determined by ELISA and anti-dsDNA by indirect immunfluorescence. Arterial and venous thrombosis were also clinically assessed. Pre-vaccination frequency of at least one aPL antibody was significantly higher in PAPS patients versus controls (58% vs. 24%, p=0.0052). The overall frequencies of aPL antibody at pre-vaccination, 3 weeks and 6 months after immunization remained unchanged in patients (p=0.89) and controls (p=0.83). The frequency of each antibody specificity for patients and controls remained stable in the three evaluated period (p > 0.05). The frequency of each antibody kept invariable in PAPS patients under chloroquine treatment (p > 0.05). At 3 weeks, 2 PAPS patients developed a new but transient aPL antibody (aCL IgG and IgM), whereas at 6 months new aPL antibodies were observed in 6 PAPS patients and none had high titer. Anti-Sm and anti-dsDNA autoantibodies were uniformly negative and no new arterial or venous thrombosis were observed throughout the study. This was the first study to demonstrate that pandemic influenza vaccine in PAPS patients does not trigger short and long-term thrombosis or a significant production of aPL related antibodies. (ClinicalTrials.gov, #NCT01151644)

Influenza A is a single-stranded, multi-segmented, negative sense RNA virus of the family Orthomyxoviridae and is the causative agent of seasonal Influenza. Influenza viruses cause significant impacts on a global scale regarding public health and economics. Annual influenza virus infections in the United States account for over 200,000 hospitalizations, up to 49,000 deaths, and an $87.1 billion economic burden. Influenza A virus has caused several pandemics since the turn of the 20th century. The effects of Influenza on public health and economics, compounded with low efficacy of the annual vaccine and emerging antiviral resistance, brings to light the need for an effort to stem these impacts, prevent pandemics, and protect public health by developing novel treatments. This project proposes an alternative approach to combatting Influenza by targeting host factors hijacked during infection that, if inhibited, significantly impair viral RNA expression, but result in low host toxicity. The host factors we examined include RNA export factors (XpoT and Xpo5) and RNA helicases (UAP56 and URH49). We selected paralogs URH49 (DDX39A) and UAP56 (DDX39B) because previous studies suggest differing roles during infection, but we theorize that their high degree of sequence similarity, similar function, and association with many of the same cellular factors may allow them to substitute for one another if one is inhibited. CRISPR was considered as the primary method to evaluate the effect of knockout of these factors on viral RNA expression and host cell toxicity. CRISPR is an RNA-guided mechanism for gene editing and can be used to make null mutations in targeted host genes. However, CRISPR proved to be a significant challenge and, while we could not conclusively confirm whether the CRISPR plasmids were effective at targeting our genes of interest, our initial results were not promising and we did not pursue this approach further. As an alternative, host RNA export factors were evaluated using siRNA to knockdown the factor prior to influenza infection. RNA was analyzed by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The potential of inhibiting UAP56 or URH49 as a novel therapeutic target was determined using a visual assessment of cell death. We found that siRNA-mediated knockdown of XpoT and Xpo5 did not have any impact on viral RNA synthesis early during infection. siRNA against UAP56 and DDX39 (targets both UAP56 and URH49) resulted in significant impairment in viral RNA synthesis, confirming previously established work suggesting that UAP56 and URH49 have important roles during infection. Importantly, these helicases play an interferon (IFN) independent role to enhance viral replication, as indicated by analysis in IFN deficient VERO cells. A viability assay relying on trypan blue exclusion did not yield trustworthy results, so a visual assessment of cell death was done. The visual assessment confirms previously-established observations that Nxf1 siRNA treatments result in a high degree of cell death, indicating the toxic nature of Nxf1 inhibition. Cells treated with UAP56 or DDX39 siRNAs demonstrated little to no additional toxicity compared to the non-target control, suggesting they can be inhibited to serve as antiviral targets.

Wild bird reservoirs of influenza A contribute to the overall genetic diversity of influenza, an increased range of endemic areas, as well as, transmission methods not commonly seen in human infections. These additions to influenza transmission increase the threat posed to human populations. Therefore, understanding the patterns of transmission of influenza A subtypes in avian hosts, as well as the environmental variables associated with transmission, is paramount to creating effective surveillance programs and forecasting potential areas of high genetic changes. Using a dataset of ~151,000 birds sample for avian influenza in the US and Canada from 1986-2017, we explore spatial patterns of influenza genotypes and model the environmental niches where certain types are found. Cluster analysis and niche modeling indicate overlap but also imperfect concordance between where each subtype of avian influenza was found and where each was predicted to circulate in wild bird populations. Overall, the Midwest and New England regions indicate higher risks of influenza A in wild birds across all flu types. In addition, the urban, wetland, and water land-cover types, as well as, low levels of human population density increase the likelihood of influenza presence in the avian populations. These results indicate that influenza transmission in wild birds is heavily affected by the activities of humans as well as the general characteristics of land cover types. Together, these results allow researchers to gain a better understanding of the spatial mechanisms of the broad scale patterns associated with influenza and the areas of particular risk associated with subtypes.

Proper mRNA nuclear export is essential for harmonious growth and maintenance of a cell. An effective weapon influenza virus employs to hijack a host cell is its ability to inhibit such export. Exactly how influenza virus achieves this inhibition is not fully known. Here, we demonstrate that upon infection, influenza virus degrades two nucleopore proteins (Nup98 and Nup96), which play a key role in mRNA nuclear export. Also, a main virulence factor of influenza virus (non-structural protein 1, NS1) binds directly to NXF1 and E1B-AP5, two key constituents of the mRNA export pathway (NXF1/NXT pathway) responsible for exporting bulk (~70%) mRNA from the nucleus. By increasing the expression levels of members of the NXF1/NXT pathway, we were able to reverse NS1-mediated inhibition of gene expression. On the other hand, by decreasing the levels of members of the NXF1/NXT pathway, we demonstrated that host cells become more sensitive to influenza virus infection and produce more viral particles. These results demonstrate undiscovered influenza-mediated host interactions that may be used to medicinally inhibit influenza virus. To this end, high-throughput screens were designed to identify small molecule antagonists of both NS1-mediated inhibition of gene expression and influenza virus-mediated cell death. Seventy-one compounds were identified, and the most potent molecule (named compound #8) was examined further. We found that compound #8 releases influenza virus-mediated mRNA nuclear export blockage and decreased viral replication and viral gene expression. Thus, the bulk mRNA nuclear export machinery is vital to antiviral response, and compound #8 enhances its ability to fight the cytopathic effects of NS1 and influenza virus. In conclusion, our data demonstrate that the mRNA export machinery is disrupted by influenza virus, and that this machinery also facilitates an antiviral function. We have also shown that these two events can be manipulated chemically to attenuate the negative effect of the virus and enhance the positive antiviral effect of the mRNA export machinery, thereby providing a powerful, new strategy against the ever-present, global threat of influenza virus.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (M. P. A.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

<p>Avian Influenza (AI) is a contagious viral zoonotic disease with great public health implications and negative socioeconomic impact (WHO, 2006a). The highly pathogenic avian influenza (HPAI) infection is transmitted from birds to man mostly through contact with contaminated poultry and objects (INFOSAN, 2005), hence people who come in contact with birds such as live bird sellers (LBS) are the more vulnerable population (WHO, 2006a). Inadequate knowledge of AI health risks and poor practice of AI preventive measures amongst LBS increases the risk of spread of the infection in both humans and animals.The aim of this study was to describe and quantify the knowledge and practice of LBS with regards to avian influenza health risks and preventive activities in Agege, an urban area in Lagos State, Nigeria.</p>

Vaccination is one of the major strategies available for combating viral infections in humans. However, currently available vaccines are not without pitfalls; they are laborious to produce, could potentially be unsafe, and in the case of the highly variable influenza virus need to be reformulated each season. The use of synthetic peptides thus represents an exciting alternative to traditional vaccines. However, these synthetic peptides are not highly immunogenic without the use of potent adjuvants. The lack of immunogenicity might be addressed by conjugation between T or B cell epitopes with universal or immunodominant T-helper epitopes. The construction of branched peptides, lipidated peptides, or designs combining both of these elements might also enhance the immunogenicity, as they might target Toll-like receptors and/or mimic the 3-dimensional structure of epitopes within the native protein. In this study, a recognized T-B peptide based on the hemagglutinin protein of the A/Puerto Rico/8/34 influenza virus was chosen as a backbone and modified to evaluate if the construction of branched peptides, lipidation, the addition of cysteine residues, or mutations could indeed alter reactivity. Screening the different designs with various antibody binding and cellular assays revealed that combining a branched design with the addition of lipid moieties leads to a greatly enhanced activity as compared to other similar T-B diepitope constructs.