Dissertations / Theses on the topic 'H3N2 virus'
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Plante, Martin. "Réponse immunitaire du porc face au virus influenza et amélioration des vaccins disponibles pour combattre ce virus." Mémoire, Université de Sherbrooke, 1996. http://savoirs.usherbrooke.ca/handle/11143/4341.
Full textMittelholzer, Camilla Maria. "Influenza virus - protection and adaptation /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-656-5/.
Full textPhillipson, Louisa. "Sialyl oligosaccharide glycopolymers : their synthesis and use as probes of the influenza A H3N2 virus evolution." Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424034.
Full textMedeiros, Rita. "Évolution des glycoprotéines des virus grippaux A (H3N2) récents : étude de leurs interactions avec les acides sialiques." Paris 7, 2002. http://www.theses.fr/2002PA077123.
Full textBergeron, Corinne. "Composition génétique de semences vaccinales H3N2 et construction d'un virus vecteur : une histoire d'encapsidation de segments chez les virus influenza de type A." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00625467.
Full textHardy, Isabelle. "Caractérisation antigénique et moléculaire des virus influenza A/H3N2 collectés dans la province de Québec lors des trois dernières saisons grippales, 1997-2000." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62067.pdf.
Full textTu, Véronique. "Évaluation in vitro de l'efficacité du peramivir contre des variants du virus de l'influenza A(H1N1), A(H3N2) et B contenant différentes mutations dans le gène de la neuraminidase." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27820.
Full textInfluenza viruses are respiratory pathogens responsible for seasonal epidemics affecting 10 to 20% of the world's population every year, thus constituting a major public health impact. Annual vaccination reduces the impact of influenza epidemics; however, a mismatch between the vaccine strain and the circulating strain can sometimes occur and result in an unsuccessful attempt in protecting the population. In such cases, it is important to have adequate treatment to treat influenza infections. Neuraminidase inhibitors (NAIs) are the primary class of antiviral agents recommended for the prevention and treatment of influenza infections. NAIs competitively bind the neuraminidase (NA) active site, blocking the release of virions from host cells and thereby inhibiting the spread of the virus into the respiratory tract. The sporadic emergence of oseltamivir- and/or zanamivir-resistant viruses with low transmission rates was identified in seasonal influenza strains. The development of new antivirals thus became an important subject of investigation. Peramivir, a new NAI recently available in North America, exerts its activity against influenza A and B viruses, but its effectiveness against mutations conferring resistance to oseltamivir or zanamivir has not yet been fully characterized. Due to differences in the binding of NAIs to the target enzyme, the nature of the resistance mutations may vary from one NAI to another, although some mutations could induce global NAI cross-resistance. We have demonstrated that peramivir is highly active against the different seasonal influenza subtypes, although some variants have shown multi-resistance phenotypes to oseltamivir, zanamivir as well as peramivir. In this regard, a new resistance mechanism by which a NA variant leads to NAI cross-resistance (I427T/Q313R) has been described in this thesis and has helped to understand how substitutions found outside the NA active site can affect the replication kinetics of the virus and its resistance to antivirals.
Barthélémy, Adeline. "Rôle des cellules T natural killer invariants (iNKT) dans la surinfection bactérienne post-grippale." Thesis, Lille 2, 2016. http://www.theses.fr/2016LIL2S002/document.
Full textXDurant 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 [...]
Oxburgh, Leif. "Studies of the evolution of the haemagglutinin protein of equine influenza virus H3N8 /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5403-4.gif.
Full textLivesay, Georgia Jane. "Field and experimental approaches to the study of of influenza A/equine-2/Suffolk/89 (H3N8) virus : construction and characterisation of vaccina virus recombinants, and their use in immunoassays." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337874.
Full textBelkacem, Nouria. "Impact de l'administration des probiotiques sur les infections respiratoires." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC195/document.
Full textProbiotics are part of the commensal microbiota. They play a potential role in stimulating the intestinal and systemic immune response. Several clinical studies addressed beneficial effect of probiotics against respiratory infections in particular on influenza infections. These infections are responsible for significant morbidity. The burden of flu is also worsened by secondary bacterial infections such as Neisseria meningitidis. In this work, we investigated the mechanisms of protection against influenza infection conferred by Lactobacillus paracasei CNCM I-1518 strain in mice. Our results showed that, L. paracasei consumption allow an early activation of pro-inflammatory cytokines and a massive recruitment of immune cells in the lungs prior to influenza infection. This activation of immune system was associated with a faster clearance of influenza virus after infection. We able to show that feeding mice with purified peptidoglycan from L. paracasei reproduced partially the above mentioned effects observed with L. paracasei bacteria feeding.The protective effects induced by L. paracasei CNCM I-1518 against the flu infection are strain specific as L. rhamnosus CNCM I-3690 and L. paracasei CNCM I-3689, tested under the same conditions did not confer to mice protection against influenza infection. Subsequently, we investigated the impact of L. paracasei CNCM I-1518 on secondary bacterial infection with N. meningitidis following influenza infection. Our results showed that consumption of L. paracasei CNCM I-1518 strain was associated with a better clinical status and a modulation of the immune response with a better clearance of secondary bacterial infection
Shi, Yanfeng. "Evolutionary forces of H3N2 type influenza A virus." 2007. http://etd.lib.fsu.edu/theses/available/etd-06292007-162133.
Full textAdvisor: David Swofford, Florida State University, College of Arts and Sciences, Dept. of Biological Science. Title and description from dissertation home page (viewed Oct. 9, 2007). Document formatted into pages; contains viii, 48, [24] pages. Includes bibliographical references.
Lin, Wei-Fan, and 林韋帆. "Genetic and antigenic analysis to the hemagglutinin of influenza A H1N1 virus and comparisons with H3N2 virus." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/82368042010601357238.
Full text國立交通大學
分子醫學與生物工程研究所
99
Influenza A virus causes significant morbidity and mortality in humans. H1N1 is one of the current circulating influenza A subtypes in human. The H1N1 pandemic occurred in the early 20th century and resulted in approximately 20 million deaths in the world. Recently, the emerged swine-origin H1N1 virus has infected human population and cause the 2009 influenza pandemic. Hemagglutinin (HA), which is an antigenic glycoprotein on the surface of influenza virus, is neutralized by antibodies during infection or vaccination. Accumulation of mutations on HA can lead to antigenic drift. The emergence and spread of antigenic variants often requires a new vaccine strain to be selected before coming epidemic. Most of studies on HA focused on the H3N2 subtype. However, the genetic evolution and antigenic evolution of the HA is poor understood for subtype A (H1N1). To study the genetic and antigenic evolution of subtype A (H1N1) is an emergent issue for public health and vaccine development. In this thesis, we performed the genetic and antigenic analysis to the HA of A (H1N1) viruses. In the sequence level, we collected 1525 HA sequences and used Shannon entropy to quantify the genetic diversity of each amino acid. In the vaccine efficacy level, we collected 202 pairs of HI assays from weekly epidemiological record (WER) and publications in last 40 years. Based on the collected Hemagglutination Inhibition (HI) assays, we applied a statistical index to quantify the antigenic score of each amino acid on HA. Finally, a decision tree tool (C4.5) was used to build a model for predicting the antigenic variants of H1N1 virus. We select 30 critical positions of H1N1 hemagglutinin by the genetic and antigenic analysis. There are 26 positions on the surface of the HA and 9 positions on the H1N1 epitopes. Based on the genetic and antigenic analysis on HA, we found that there are two sites with both high genetic diversity and antigenic score in A (H1N1) virus. These two sites include one site around the receptor binding site and the other antigenic site about 45 Å distant from receptor binding site. In contrast, there is only one site, which is around the receptor binding site, have high genetic diversity and high antigenic in A (H3N2) virus. By comparing the HA of two subtypes of influenza A virus, we found that some amino acid positions locating on the antigenic sites of influenza A (H3N2) virus are potential epitope residues for influenza A (H1N1) virus. In addition, the accuracy of our model for predicting antigenic variants was 85% by using HA sequences as input. We believe that our methods are useful for the vaccine development and understanding the genetic and antigenic evolution of influenza A (H1N1) virus.
Chang, Hsin-Yi, and 張心怡. "Genetic variation in neuraminidase gene of influenza A/H3N2 virus in northern Taiwan, 2000-2004." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/53142568387684637330.
Full text國立臺灣大學
醫事技術學研究所
93
Influenza virus is a member of Orthomyxoviridae, and infection of influenza virus can cause severe morbidity and mortality in the elderly and children. Influenza A viruses are enveloped and have two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Both of HA and NA undergo antigenic shift and antigenic drift. Antibody to HA is the most important determinant of immunity because it can neutralize the infectivity of influenza virus. Although anti-NA antibodies do not neutralize virus infectivity, they appear to modify the disease and reduce both pulmonary virus titer and the extent of lung lesions. Therefore, antigenic variability of the NA protein should also be considered when analyzing the epidemic impact of influenza virus and predicting newly emerging viruses. However, limited information is available concerning the molecular change of the influenza NA genes. Analysis of NA gene is particularly important since the use of influenza NA inhibitors that target the highly conserved catalytic site of the enzyme. In order to understand the variation of NA gene of influenza A (H3N2) virus in northern Taiwan, 43 strains of clinical isolates in Taipei during 2000-2004 were collected for this study. The result indicated that the amino acid variation rate of NA was about 0.5% per year. As compared with the A/Moscow/10/99 vaccine strain, amino acid changes within at least one of the seven NA antigenic determinants (I-VII) were found in approximate half of the isolates (20/43) and the most common changes were at position 332, 401, 431 and 432. Only one amino acid change (D151G) was observed in the catalytic site of NA. All isolates contained the seven conserved asparagine-linked glycosylation sites found in the NA of the progenitor A/Hong Kong/8/68 strain. In addition, most strains (38/43) had the new glycosylation sites at positions 93 and 329. To understand whether there is gene reassortment recently, we also analyzed the evolutionary relationship of these isolates. It appears that no HA/NA reassortment was found. Variation of plaque size was observed in the plaque assay. After purification of virus, a small-plaque virus strain (NA-) was obtained and a 586 nucleotide deletion (303-888nt) of NA gene was found. Although the deficiency of NA enzyme activity, it still can grow in MDCK cell. However, the virus yield was 45-fold less than wild-type when low MOI (10-5) was used. The receptor-binding ability of the defective virus was low but no compensatory substitutions in the HA gene were found. TamifluTM, a kind of anti-influenza drug, did not influence on NA- virus in vitro. Thus, our results suggest that NA activity may not be essential for influenza A virus growth.
Li-LingKao and 高麗玲. "The effect of NS1 genetic variations of H3N2 influenza A virus on type I interferon." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95355038184727641748.
Full text國立成功大學
醫學檢驗生物技術學系碩博士班
100
Influenza A virus is an important pathogen with worldwide prevalence. The major circulating subtypes are H3N2 and H1N1. Influenza A virus contains 8 negative stranded RNA segments that encode 11 or 12 viral proteins. Among them, NS (non-structural) gene encodes NS1 protein which can increase viral pathogenicity and virulence by regulating viral translation and antagonizing host defense immune responses, especially type I interferon (IFN-α/β) production and antiviral activities of IFN-induced proteins. Our phylogenetic analysis of NS genes of H3N2 viruses from 1999 to 2011 showed that most NS genes fall into one group, H3 group, except that NS genes of 2002 isolates (H3 variants, H3v) were separated into another group, H3v group. Two amino acid changes, E71G in the RNA binding domain and V82A in the effector domain, were identified in NS1 proteins of these 2002 isolates. To test whether these amino acid mutations contribute to IFN response, we investigated IFN-β protein production, IFN-β promoter activity and IFN-α susceptibility of isolates in H3 group and H3v group. The result showed that the H3 variants induced higher IFN-β protein production and IFN-β promoter activity. In addition, the H3 variants showed comparable reduction to other isolates in virus productions when pretreated A549 cell with IFN-α. The result indicated that the two substitutions V82A and E71G in NS1 protein of H3 variants can affect the IFN-β protein level and promoter activation. We further constructed recombinant NS1 protein to elucidate the effect of E71G and V82A mutations on IFN-β and ISRE promoter activity. Recombinant NS1 proteins with E71G or double mutation of E71G/V82A substitution showed higher induction of IFN-β promoter than NS1 protein from H3 group. Interestingly, recombinant NS1 proteins with either substitution exhibited stronger inhibitory effects on ISRE promoter activity when compared with H3 NS1. We further investigated the effect of recombinant virus with difference in NS gene sequence on replication curve. It showed that the replication ability of recombinant virus with different NS gene were similar. Our results indicated that NS1 with E71G and V82A mutations may affect type I IFN response in the IFN-β protein secretion, promoter activation and the downstream pathway of IFN-β which may be the disadvantage to virus infection and lead to disappearance in the later season. The substitutions in NS1 can be applied to vaccine strain development. Our study will be helpful to understand the contribution of NS1 genetic variation to the pathogenesis of influenza viruses.
Hagembe, Juliana Liambaya. "Effect of antigenic site mutations on the binding specificity of an anti-hemagglutinin antibody to H3N2 influenza virus isolates." 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1467107.
Full textHung, Ying-Nien, and 洪宜年. "A longitudinal study of cross-reactive antibody to swine influenza A virus (H3N2) and serologic evaluation of different influenza viruses after 2009 pandemic H1N1 in Taiwan." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/32660824464898926498.
Full text國立中興大學
微生物暨公共衛生學研究所
100
Introduction: Pigs play an important role in gene reassortment of the eight RNA segments of influenza viruses since they are susceptible to the viruses with both avian and human origin. Because of the great change of antigenicity, the reassorted viruses have the potential to cause global pandemic such as 2009 pandemic H1N1. As the reports of the increase of human infection by the newly-reassorted swine influenza viruses subtype H3N2 carrying genes from 2009 pandemic H1N1 were observed, it is crucial to understand the antibody cross-reactivity between swine and human-origin H3N2 as well as the protection provided by the seasonal influenza vaccination (TIV). Besides, this study would evaluate different vaccination strategies as well as the changes of vaccine component on the sustainability of antibody against. In this study, we used hemagglutination inhibition (HI) assay to test the antibody distribution. Results: (1) The swine-origin H3N2 viruses used in this study included A/Swine/Taiwan ex USA/28-9/2010, A/Swine/Taichung/50-1/2004, A/Swine/Yunlin/113-3/2010, and A/Swine/Obihiro/10/1985 from Japan. The HA lineage of A/Swine/Taiwan ex USA/28-9/2010 was from 2005-like human influenza and others were from 1980s-like human influenza. Human sera were collected from school-aged children as well as their family adults at Taichung and Nantou between 2008 and 2010 before and after seasonal influenza vaccination. The results showed that GMT and seroprotection rate against Taiwan swine influenza were gradually elevated with increasing age with GMT from 5 to 10.315 and the seroprotection rate from 0 to 23.59% of the young and old age group, respectively. However, the titer decreased through year in adults with GMT from 14.42 to 5.8 and the seroprotection rate from 38.83 to 2.68% during 2008 and 2010, respectively. (2) The results of receiving different vaccination strategies showed that the seroprotection rate of grade 4-6 with 2009 pandemic vaccine only decreased to 64.71 % before 2010 vaccination, while grade 1-3 were 82.76 %. Furthermore, the seroprotection rate of grade 4-6 was significant lower in group 1 (64.71 %) than in group 2 (94.30 %) before 2010 vaccination. (3) The only vaccine component changed was H3N2 during 2010-11 season. Although receiving TIV from both seasons (2009-10 and 2010-11) had significant higher GMT and seroprotection rate in H1N1 (2009 and 2010 vaccine strains were the same), antibody response was significant lower in H3N2 (2009 and 2010 vaccine strains were different), compared to the group receiving only TIV during 2010-11 season. Conclusion: Our data demonstrated that both children and adults are susceptible to the infection by swine influenza virus and suggested the necessity of specific vaccine against newly-reassorted pandemic virus from pigs because of the low cross-reactivity between seasonal TIV and swine influenza viruses. Furthermore, boosting of the same vaccine strain would enhance immune response, while the change of vaccine strain might reduce the ability of enhancing antibody response among school-aged children.
Mhamdi, Zeineb. "Variations génomiques et antigéniques du virus de la grippe porcine (Influenzavirus porcin) sur le territoire québécois." Thèse, 2016. http://hdl.handle.net/1866/18651.
Full textData about genomic variability of swine influenza A viruses (SIV) in Quebec herds are scarce. Yet, this information is important for understanding virus evolution in Quebec from until 2015. Different clinical samples were obtained from 24 outbreaks of swine flu in which animals were experiencing respiratory disease. Samples including lung tissues, saliva and nasal swabs were collected and virus isolation was attempted in MDCK cells and embryonated eggs. All eight gene segments of the 18 isolated SIV strains were sequenced and analysed. Antiviral drugs resistance against oseltamivir carboxylate (GS4071), zanamivir (GS167) and amantadine hydrochloride was evaluated by neuraminidase inhibition assays (NAIs) and plaque reduction assay. Two subtypes of SIV, H3N2 and H1N1, were identified in Quebec pig herds. Twelve SIV strains were genetically related to trH3N2 Cluster IV and at least 6 different reassortment profiles were identified. On the other hand, 6 Quebec SIV strains were found to be genetically related to the pandemic virus A(H1N1)pdm09 and from which three reassortment profiles were identified. Overall, the trH3N2 was the most prevalent subtype (66.7%) found in Quebec swine herds. The epitope mapping of HA indicated that the H3 subtype was the most variable with a possibility of 21 amino acids (aa) substitutions within the 5 antigenic sites A(5), B(8), C(5), D(1) and E(2). However, the HA protein of the H1 subtype had only 5 aa substitutions within 3 antigenic sites Sb(1), Ca1(2) and Ca2(2). One H1N1 (1/6 = 16.7%) and one trH3N2 (1/12 = 8.3%) were identified as strains resistant against oseltamivir. In contrast, two H1N1 (2/6 = 33.3%) and two trH3N2 (2/12 = 16.7%) strains were found to be resistant against zanamivir. Overall, the SIV resistance against antiviral neuraminidase inhibitor drugs was (33.3%). All strains were resistant against the M2 inhibitor antiviral drug, amantadine. The presence of antiviral drug resistance in Quebec swine herds and the possible emergence of new SIVs strains are public health concerns supporting the surveillance of SIVs.
Najar, Tariq Ahmad. "Design and Stabilization of Stem Derived Immunogens from HA of Influenza A Viruses." Thesis, 2015. http://etd.iisc.ernet.in/2005/3863.
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