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Imunocaptura do vírus de Influenza aviária para dia diagnóstico em RT-PCR em tempo realDi Pillo, Fulvia [UNESP] 13 August 2010 (has links) (PDF)
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dipillo_f_me_jabo.pdf: 266438 bytes, checksum: 248a318a5e5422d95006058e8dd1370a (MD5) / A técnica de imunocaptura associada com a reação de transcrição reversa e reação em cadeia da polimerase (IC-RT-PCR) executadas tanto pelos procedimentos convencional como em tempo real foram testadas para a detecção rápida do gene da glicoproteína de Matriz (M) do vírus de influenza aviária (AIV) em amostras de líquido cório-alantóide (LCA) e em suabes traqueais e cloacais. O presente trabalho teve como objetivo desenvolver e otimizar a técnica de IC-RT-PCR para o diagnóstico do vírus da Influenza aviária. Os resultados obtidos foram comparados com um sistema empregando “beads” magnéticas em microplacas (AMBION), que é o método padrão de extração de RNA usado no laboratório de referência para diagnóstico de influenza aviária, o National Veterinary Services Laboratory – Ames, EUA (USDA), acrescido ainda de outros métodos de extração tradicionalmente usados nos laboratórios de referência para AIV, como os procedimentos com o uso do solvente orgânico Trizol® (Invitrogen) e com um sistema robotizado e que utiliza “beads” magnéticas (MagNA Pure - ROCHE). A técnica de IC-RT-PCR em tempo real neste estudo detectou a estirpe H2N2 do AIV, sem que nenhum outro dos RNA-vírus heterólogos testados fossem detectados (vírus das doença de Gumboro, de Newcastle e da bronquite infecciosa aviária). Os limites de detecção do IC-RTPCR foram iguais aos obtidos na técnica de extração com o kit da AMBION e menores do que aqueles que foram observados para os métodos de extração com Trizol® (Invitrogen) e com o MagNA Pure. O IC-RT-PCR demonstrou ser um sistema de diagnóstico capaz de conciliar simplicidade operacional e um menor custo com sensibilidade e especificidade analíticas iguais às do procedimento padrão atualmente adotado, podendo ser inclusive por laboratórios dotados de uma infra-estrutura mais simples / The polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR), including real-time RT-PCR have been used for the rapid detection of Matrix glycoprotein gene (M gene) Avian influenza virus (AIV). Despite the availability of various RNA extraction methods for using in RT-PCR, isolation and detection of viral RNA are still difficult due to the unstable nature of viral RNA molecules and the presence of PCR inhibitory substances. In this study, a simple method using immune-capture (IC) to recover viral RNA from H2 AIV samples was developed and compared to one standard and two others reference methods used for viral RNA extraction, such as Ambion MagMAXTM kit and Trizol® (Invitrogen) and Magnapure kit (Roche), respectively, with subsequent analysis by real-time RT-PCR. The real-time IC-RT-PCR developed in was able to detect specifically H2N2 AIV strain, without detecting non-related avian RNA-virus pathogens, such as Newcastle disease virus, avian infectious bronchitis virus and Gumboro disease virus. Comparable detection limits were found for IC and the standard RNA extraction method using Ambion MagMAXTM kit, either for the detection of AIV in allantoic fluid suspension or in seeded tracheal and cloacal swab samples by conventional or real time RT-PCR techniques. These methods were less sensitive than Trizol® (Invitrogen) and Magnapure kit (Roche) procedures. Thus, IC was rapid and as sensitive and specific as current standard AIV RNA extraction method for real time or conventional RT-PCR, besides it conciliated simplicity and lower cost and can be applied simultaneously for direct detection of AIV in a large number of samples, including less-equipped laboratories
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Estudo etiológico e patológico de pneumonias em javalis criados de forma confinada no estado do Rio Grande do Sul / Etiological and pathological study of pneumonia in captive wild-boars in the state of Rio Grande do SulBiondo, Natalha January 2012 (has links)
As doenças respiratórias são muito comuns na produção intensiva de suínos, já em javalis são escassas informações sobre prevalência, etiologia e apresentação clínico-patológica destas enfermidades. No entanto, a presença de patógenos respiratórios comuns entre javalis selvagens e confinados e suínos domésticos já foi relatada. Este trabalho descreve as principais lesões macroscópicas e histológicas de pneumonias de javalis e os agentes comumente envolvidos. Foram examinados pulmões de javalis, ao abate, provenientes de criatórios comerciais e a principal lesão macroscópica foi consolidação crânio-ventral dos lobos craniais e médios e lesões crônicas cursando com hiperplasia linfóide na histologia. O principal agente bacteriano detectado foi o Mycoplasma hyopneumoniae (58,6%). Outros patógenos bacterianos detectados foram Actinobacillus pleuropneumoniae (48,8%), Haemophilus parasuis (49,6%), Mycoplasma hyorhinis (41,3%), Pasteurella multocida (9,1%) e Streptococcus suis (9,1%). Na segunda parte do trabalho, a pesquisa de patógenos virais foi direcionada para o Vírus da influenza suína (VIS) com objetivo de estudar o envolvimento em pneumonias de javalis de criatórios e a relação com agentes bacterianos encontrados. O vírus pandêmico A/H1N1/2009 foi detectado em 18,3% (11/60) e sua identidade foi confirmada por sequenciamento. A carga viral para H1N1 clássico variou de 4,58 a 6275 cópias/μL e para o H1N1 pandêmico, de 4,65 a 3863 cópias/μL. Nenhuma amostra apresentou título viral após a inoculação em ovos embrionados. As lesões histológicas principais foram broncopneumonia crônica difusa e pneumonia intersticial mononuclear leve, além de hiperplasia linfóide. As amostras positivas por RT-PCR para o VIS para o pH1N1 foram testadas por IHQ, sendo todas negativas para influenza A, mas todas eram positivas para M. hyopneumoniae. Quando testadas por bacteriologia, 18,2% das amostras foram positivas para P. multocida. O estudo mostrou que as pneumonias em javalis de criatório apresentaram lesões e patógenos associados similares aos encontrados em suínos domésticos ao abate. Este é o primeiro relato da infecção pelo vírus pH1N1 em javalis no Brasil. / Respiratory diseases are very common in swine intensive production, although in wild-boars the knowledge of the prevalence, etiology and clinic-pathological presentation of these diseases are very limited. However, the presence of common respiratory pathogens among wild-boar, captive wild-boar and domestic pigs has been reported. This paper describes the main macroscopic and histologic pneumonic lesions of captive wild-boars and pathogens commonly involved. Captive wild-boar lungs at slaughter were examined and the main macroscopic lesion observed was cranio-ventral consolidation of cranial and middle lobes and chronic lesions associated with lymphoid hyperplasia by histology. The main bacterial pathogen detected was Mycoplasma hyopneumoniae (58.6%). Other bacterial pathogens detected were Actinobacillus pleuropneumoniae (48.8%), Haemophilus parasuis (49.6%), Mycoplasma hyorhinis (41.3%), Pasteurella multocida (9.1%) and Streptococcus suis (9.1%). In the second part of this work, the survey of viral pathogens was directed to swine influenza virus (SIV) in order to study the involvement in captive wild-boar pneumonias and the relation with bacterial pathogens. The A/H1N1/2009 pandemic virus was detected in 18.3% (11/60) and its identity was confirmed by sequencing. The classical H1N1 viral load ranged from 4.58 to 6275 copies/uL and the pandemic H1N1, from 4.65 to 3863 copies/uL. No samples had viral titers after inoculation in embryonated eggs. The main histological lesions were chronic diffuse bronchopneumonia and interstitial mononuclear pneumonia as well as mild lymphoid hyperplasia. Samples positive to pH1N1 were assayed by IHC for SIV, all with negative results, and to M. hyopneumoniae, all were positive. When assayed by bacteriology, 18.2% of samples were positive to P. multocida. This study showed that pneumonia in captive wild-boar had similar lesions and associated pathogens were similar to those found in domestic pigs at slaughter. This is the first report of pH1N1 virus infection in captive wild-boars in Brazil.
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Estudo etiológico e patológico de pneumonias em javalis criados de forma confinada no estado do Rio Grande do Sul / Etiological and pathological study of pneumonia in captive wild-boars in the state of Rio Grande do SulBiondo, Natalha January 2012 (has links)
As doenças respiratórias são muito comuns na produção intensiva de suínos, já em javalis são escassas informações sobre prevalência, etiologia e apresentação clínico-patológica destas enfermidades. No entanto, a presença de patógenos respiratórios comuns entre javalis selvagens e confinados e suínos domésticos já foi relatada. Este trabalho descreve as principais lesões macroscópicas e histológicas de pneumonias de javalis e os agentes comumente envolvidos. Foram examinados pulmões de javalis, ao abate, provenientes de criatórios comerciais e a principal lesão macroscópica foi consolidação crânio-ventral dos lobos craniais e médios e lesões crônicas cursando com hiperplasia linfóide na histologia. O principal agente bacteriano detectado foi o Mycoplasma hyopneumoniae (58,6%). Outros patógenos bacterianos detectados foram Actinobacillus pleuropneumoniae (48,8%), Haemophilus parasuis (49,6%), Mycoplasma hyorhinis (41,3%), Pasteurella multocida (9,1%) e Streptococcus suis (9,1%). Na segunda parte do trabalho, a pesquisa de patógenos virais foi direcionada para o Vírus da influenza suína (VIS) com objetivo de estudar o envolvimento em pneumonias de javalis de criatórios e a relação com agentes bacterianos encontrados. O vírus pandêmico A/H1N1/2009 foi detectado em 18,3% (11/60) e sua identidade foi confirmada por sequenciamento. A carga viral para H1N1 clássico variou de 4,58 a 6275 cópias/μL e para o H1N1 pandêmico, de 4,65 a 3863 cópias/μL. Nenhuma amostra apresentou título viral após a inoculação em ovos embrionados. As lesões histológicas principais foram broncopneumonia crônica difusa e pneumonia intersticial mononuclear leve, além de hiperplasia linfóide. As amostras positivas por RT-PCR para o VIS para o pH1N1 foram testadas por IHQ, sendo todas negativas para influenza A, mas todas eram positivas para M. hyopneumoniae. Quando testadas por bacteriologia, 18,2% das amostras foram positivas para P. multocida. O estudo mostrou que as pneumonias em javalis de criatório apresentaram lesões e patógenos associados similares aos encontrados em suínos domésticos ao abate. Este é o primeiro relato da infecção pelo vírus pH1N1 em javalis no Brasil. / Respiratory diseases are very common in swine intensive production, although in wild-boars the knowledge of the prevalence, etiology and clinic-pathological presentation of these diseases are very limited. However, the presence of common respiratory pathogens among wild-boar, captive wild-boar and domestic pigs has been reported. This paper describes the main macroscopic and histologic pneumonic lesions of captive wild-boars and pathogens commonly involved. Captive wild-boar lungs at slaughter were examined and the main macroscopic lesion observed was cranio-ventral consolidation of cranial and middle lobes and chronic lesions associated with lymphoid hyperplasia by histology. The main bacterial pathogen detected was Mycoplasma hyopneumoniae (58.6%). Other bacterial pathogens detected were Actinobacillus pleuropneumoniae (48.8%), Haemophilus parasuis (49.6%), Mycoplasma hyorhinis (41.3%), Pasteurella multocida (9.1%) and Streptococcus suis (9.1%). In the second part of this work, the survey of viral pathogens was directed to swine influenza virus (SIV) in order to study the involvement in captive wild-boar pneumonias and the relation with bacterial pathogens. The A/H1N1/2009 pandemic virus was detected in 18.3% (11/60) and its identity was confirmed by sequencing. The classical H1N1 viral load ranged from 4.58 to 6275 copies/uL and the pandemic H1N1, from 4.65 to 3863 copies/uL. No samples had viral titers after inoculation in embryonated eggs. The main histological lesions were chronic diffuse bronchopneumonia and interstitial mononuclear pneumonia as well as mild lymphoid hyperplasia. Samples positive to pH1N1 were assayed by IHC for SIV, all with negative results, and to M. hyopneumoniae, all were positive. When assayed by bacteriology, 18.2% of samples were positive to P. multocida. This study showed that pneumonia in captive wild-boar had similar lesions and associated pathogens were similar to those found in domestic pigs at slaughter. This is the first report of pH1N1 virus infection in captive wild-boars in Brazil.
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Identification phénotypique et fonctionnelle des cellules dendritiques et macrophages pulmonaires porcins à l’état basal et lors d’infections influenza / Phenotypic and functionnal identification of the porcine pulmonary Dendritic Cells and Macrophages at steady-state and upon Influenza InfectionsMaisonnasse, Pauline 24 February 2016 (has links)
Le porc est un modèle d’étude présentant à la fois une grande importance agronomique et un fort potentiel comme modèle biomédical pour différentes pathologies respiratoires. Pourtant, son système immunitaire pulmonaire est peu connu, limitant l’approfondissement de ces études. Notamment, les cellules dendritiques (DCs) et macrophages (Mθs) tissulaires, qui sont à l’interface entre immunités innée et acquise, n’étaient pas caractérisés. L’objectif de cette thèse était de décrire ces cellules dans le poumon porcin à l’état basal et durant des infections par différentes souches de virus Influenza A (VIA), un pathogène capable d’infecter le porc et l’Homme. Nous avons caractérisé pour la première fois les DCs conventionnelles (cDCs) et dérivées de monocytes (moDCs), ainsi que des macrophages dérivés de monocytes (moMθs) et les macrophages alvéolaires (AMs) porcins. Les cDC1 et cDC2 se sont révélées proches de leurs équivalentes murines et humaines de par leur phénotype et leurs capacités de migration et de présentation de l’antigène in vitro. Les moDCs sont, comme chez la souris, pro-inflammatoires et recrutées lors d’une infection par le VIA in vivo. Nous avons également étudié des cellules tissulaires fortement représentées dans le poumon porcin et dont le phénotype est très similaire à celui des AMs : les cellules AM-like. Ces dernières sont pro-inflammatoires lors d’infections in vitro par un virus H3N2 porcin ou une souche Lena du PRRSV. Nous avons enfin étudié ces différents types cellulaires dans le cadre d’infections par deux souches porcines du VIA, l’une du sous-type H3N2 et l’autre du sous-type H1N2, la première étant plus pathologique en élevage et induisant plus d’inflammation. Il se pourrait que les cellules AM-like aient un rôle important dans cette différence de pathogénicité. En conclusion, nous avons mis en place des moyens pour étudier plus précisément le rôle des DCs et Mθs dans le poumon porcin, et ainsi, de mieux comprendre l’inflammation et la réponse immunitaire pulmonaire. Ce travail ouvre des voies, en santés vétérinaire et biomédicale, qui étaient jusqu’à présent réservées au modèle murin. / Pig is a research model with a major agronomic importance and a great potential as a biomedical model for different respiratory pathologies. Yet, its pulmonary immune system is little known, limiting the deepening of these studies. In particular, tissular Dendritic Cells (DCs) and Macrophages (Mθs), which are at the interface between innate and adaptive immune systems, were not characterized. The aim of this thesis was to describe DCs and Mθs in the porcine lung at steady-state and during infections with different strains of influenza virus A (IAV), a pathogen capable of infecting pigs and humans. We characterized for the first time conventional DCs (cDCs) and monocyte derived (moDCs), as well as monocyte-derived macrophages (moMθs) and alveolar macrophages (AMs) in pig. The cDC1 and cDC2 were phenotypically close to their murine and human equivalents. They also had the same in vitro capabilities of migration and antigen presentation. The moDCs are, like murine ones, pro-inflammatory and are recruited during an IAV infection in vivo. We also found a highly represented interstitial population whose phenotype is very similar to that of AMs: AM-like cells. They are pro-inflammatory upon in vitro infection by a swine H3N2 strain or a Lena strain of PRRSV. Finally, we studied these different cell types through infection by two strains of porcine IAV, an H3N2 and an H1N2 strains, the first one being more pathological and inducing more inflammation. The AM-like cells might play an important role in this pathogenicity difference. In conclusion, we found a strategy to study more precisely the roles of DCs and Mθs in the porcine lung, and thus to better understand lung inflammation and immune response. This work opens pathways, in veterinary and biomedical health, which were previously reserved for mouse model.
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Investigation of seasonal prevalence of low pathogenic avian influenza (LPAI) in a heterogeneous wild waterfowl population in Pretoria.Phiri, Thandeka P. 06 1900 (has links)
M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Science), Vaal University of Technology. / Influenza-A virus is a single stranded negative sense RNA virus that is a member of a Orthomyxoviridae group. The virus is diverse and consists of 16 haemagglutinin (H) and 9 neuraminidase (N) glycoproteins subtypes that form a serotype. Avian influenza virus (AIV) has been detected in more than 100 bird species from 26 different families, although Anseriformes and Charadriiformes are considered the natural hosts of the virus. A 12-month study was conducted at the African Pride Irene Country Club lodge in Pretoria where the prevalence of AIV was monitored in a community of wild birds. The African Pride Irene Country Club lodge houses a population of wild bird species such as Egyptian geese (Alopochen aegytptiaca), Yellow-billed duck (Anas undulata), Red knobbed coot (Fulica cristata), African sacred ibis (Threskiornis aethiopicus) and Hadeda ibis (Bostrycha hagedash). A total of 3674 faecal samples were collected over a period of 12 months and screened for AIV group using the Matrix gene (M-gene) real time reverse-transcriptase PCR (rRT-PCR). Positive samples were submitted for virus isolation in embryonated chicken eggs. In addition, the RNAs were screened using H5 and H7 subtype specific rRT-PCR and a conventional universal RCR assay that targets the HA gene was also used. Polymerase Chain Reaction (PCR) products were requenced using Sanger sequencing and the viral isolates were subjected to Next Generation sequencing (NGS). Twenty percent of the samples tested positive for the AIV group and four virus subtypes were identified. One virus isolate was identified through NGS as H3N6; two through conventional PCR and Sanger sequencing as H9Nx and H6Nx. Of the twenty percent samples that tested positive for AIV 98% were identified as H7Nx by subtype specific through rRT-PCR. The highest frequency of AIV positive samples was detected between the months of January and February 2017 (20%), with smaller peaks detected in february and March 2016 (0.3%). Lower peaks were also detected between the months July and November 2016 (0.1%), respectively. A high prevalence of AIV was detected in the late summer months with a frequency of 65% positive, although a low prevalence was also detected in the autumn (0.6%) winter (0.6%) and spring 0.08%). Thus, the study provides a valuable insight into the seasonal prevalence of AIV in a heterogeneous wild duck population in Gauteng Province.
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Studies on the novel bioactive peptide screening systems for G-protein coupled receptors and neuraminidase / Gタンパク質共役受容体およびノイラミニダーゼを標的とした生理活性ペプチドの新規機能的探索法に関する研究Shigemori, Tomohiro 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19048号 / 農博第2126号 / 新制||農||1032(附属図書館) / 学位論文||H27||N4930(農学部図書室) / 31999 / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 植田 充美, 教授 植田 和光, 教授 小川 順 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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In Vivo Characterization of Pathologies Associated with Severe Influenza Virus InfectionKenney, Adam D. January 2021 (has links)
No description available.
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Hemagglutinin reassortment dynamics of the zoonotic H9N2 avian influenza virusMannsverk, Steinar S January 2020 (has links)
The H9N2 avian influenza virus (AIV) has emerged, spread and established itself in poultry globally, in just under 30 years. During this time, multiple reassortants of H9N2 with increased zoonotic potential have been isolated in poultry and humans, causing a major threat to the economy and global health. Curiously, H9N2 appears to be compatible with multiple Hemagglutinin (HA) and Neuraminidase subtypes, in nature. Here, the aim was to investigate the HA reassortment dynamics of the poultry adapted H9N2 AIV, in a laboratory setting. Firstly, HA subtypes from wild bird isolates were cloned, before being co-transfected with the backbone of a chicken H9N2 AIV. The rescued H9N2 reassortants were titred on cells before the replication kinetics of a subset of the HA reassortants was assessed. The cDNA sequence of seven HA subtypes induced extensive recombination in E. coli, but ultimately ten out of eleven available HA subtypes were successfully cloned. Further, the chicken H9N2 AIV was compatible with all ten HA subtypes, producing infectious viral particles after co-transfection. However, all HA reassortants displayed decreased replicative fitness in MDCK-2 cells, compared to the wild-type virus. Interestingly, HA subtypes with similar genotypes cluster into distinct HA clades and groups, but these HA clades did not correlate with the replicative fitness of the reassortants. This study suggests that poultry adapted H9N2 AIV is compatible with many HA subtypes, highlighting the importance of reducing its spread in poultry, to reduce reassortment opportunities.
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Study towards the development of broadly reactive live attenuated influenza vaccines with focus on high interferon inducing viral subpopulationsGhorbani, Amir 15 September 2022 (has links)
No description available.
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Assembly von Influenzaviren / Analyse von Protein-Protein- und Protein-Lipid-Interaktionen mittels biochemischer und biophysikalischer MethodenEngel, Stephanie Vanessa 23 April 2009 (has links)
Es wird angenommen, dass das Influenzavirus-Glykoprotein Hämagglutinin (HA) für seine Funktion sowohl bei der Virusfreisetzung als auch bei der Fusion von viraler und zellulärer Membran mit Cholesterin- und Sphingolipidreichen Domänen, sogenannten Membran-Rafts, assoziiert sein muss. Aus diesem Grund sollte in dieser Arbeit die Membran-Raft-Affinität von HA in lebenden Zellen mittels FLIM-FRET gemessen werden. Dabei wurde mit Hilfe der Fluroreszenz-Lebenszeit-Messung (FLIM) der Förster-Resonanz-Energie-Transfer (FRET) von fluoreszenzmarkiertem HA auf einen etablierten Raft-Marker bestimmt. Diese Messungen zeigten, dass beide Proteine in gemeinsamen Klustern in der Plasmamembran vorkommen. Durch Cholesterinentzug und durch den Einsatz von Cytochalasin D, welches die Mikrofilamente zerstört, konnte diese Klusterbildung reduziert werden. Demnach tragen sowohl die Membran-Rafts als auch das Aktinnetzwerk zu dieser Klusterbildung bei. Mittels FLIM-FRET konnte zusätzlich bestätigt werden, dass die Signale für die Detergenslöslichkeit von HA in Triton-Extraktionsexperimenten, die Palmitylierung und die stark hydrophoben Aminosäuren zu Beginn der Transmembrandomäne (TMD), auch im lebenden System eine wichtige Rolle spielen. Zusätzlich konnten biochemische Experimente zeigen, dass die hydrophoben Aminosäuren zu Beginn der HA-TMD den intrazellulären Transport, nach der Trimerbildung, entscheidend verzögern. Diese Verzögerung ist vermutlich auf einer erschwerten Integration dieser Proteine in die Membran-Rafts begründet. Die virale Fusion mit der Wirtszellmembran wird durch eine pH5-Behandlung vermittelte Konformationsänderung von HA ausgelöst. FLIM-FRET-Messungen zeigten für die pH5-Konformation von HA eine verglichen mit der pH7-Konformation verringerte Klusterbildung mit dem Raft-Marker. Somit ist offensichtlich, dass die Membranfusion-vermittelnde HA-Konformation eine verringerte Raft-Affinität besitzt. Diese verringerte Raft-Affinität könnte eine wichtige Rolle bei der Störung der Lipide an der Fusionsstelle spielen und somit die Bildung und/oder Vergrößerung der Fusionspore erleichtern. / It has been supposed that the hemagglutinin (HA) of influenza virus is recruited to cholesterol- and sphingolipid-enriched domains, also named membrane-rafts, to accomplish its function in virus budding and membrane fusion. This study aimed at verifying the affinity of HA for membrane-rafts in living cells using fluorescence-lifetime imaging microscopy to measure Förster’s resonance energy transfer (FLIM-FRET). FLIM-FRET revealed strong clustering between a fluorescence-tagged HA-protein and a well-established raft-marker in CHO cells. Clustering was significantly reduced when rafts were disintegrated by cholesterol depletion and when microfilaments were disrupted with cytochalasin D. Thus, membrane-rafts as well as the actin meshwork contribute synergistically to clustering. Clustering was also reduced by the removal of the known signals for the association of HA with detergent-resistant-membranes, the palmitoylation and the first amino acids in the transmembrane region (TMR). Since these mutations are obviously important for the raft-association of HA their function during the transport through the ER and the Golgi-complex was studied. These investigations showed that the exchange of the first three amino acids of the HA-TMR led to a decelerated transport after trimer-formation of the protein, probably due to retarded integration of these proteins into membrane-raft domains. Mediating viral fusion with the host cell membrane requires an irreversible conformational change of HA. FLIM-FRET studies of this low pH conformation unveiled that the clustering with the raft-marker is decisively reduced compared to the pre-fusion conformation of the protein. It might be assumed that the fusion-mediating conformation of HA reduces the proteins affinity for membrane-rafts. Therefore it is likely that this reduced affinity for rafts after the conformational change is relevant to cause perturbation of lipids at the fusion site and thereby facilitating the formation and/or enlargement of the fusion pore.
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