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Dissertations / Theses on the topic 'Antiviral immunity'

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Published: 4 June 2021

Last updated: 10 July 2025

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Arnaout, Ramy A. "Mathematical models of antiviral immunity." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325989.

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Palmer, William Hunt. "Evolution and genetics of antiviral immunity in Drosophila." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31557.

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Virus-host interactions determine virus transmissibility and virulence, and underlie coevolution that shapes interesting biological phenomena such as the genetic architecture of host resistance and host range. Characterization of the virus factors that exert selective pressure on the host, and the host genes which underlie resistance and adaptation against viruses will help to define the mechanistic pathways embroiled in host-virus coevolution. In this thesis, I describe the viral causes and host consequences of host-virus coevolution. These include genomic signatures consistent with antagonistic coevolution in antiviral RNA interference pathway genes such as high rates of positive selection and polymorphism, loci that underlie genetic variation in resistance to virus infection, and apparent conflict between NF-κB signalling and DNA virus infection. The RNA interference (RNAi) pathway is the most general innate immune pathway in insects, underlined by the observation that many viruses encode suppressors of RNAi (VSRs). The relationship between RNAi and VSRs has garnered attention as a plausible battleground for host-virus antagonistic coevolution, and genomic patterns in Drosophila support this hypothesis. However, genomic patterns in the N-terminal domain of the key RNAi effector gene, Argonaute-2, have not been described. In Chapter 2, I sequence the Argonaute-2 N-terminal domain using PacBio long-read sequencing technology to describe variation within and across Drosophila species, and test whether this variation is associated with resistance to Drosophila C Virus. The RNAi pathway evolves adaptively in Drosophila, but this has not been formally extended across invertebrate species. In Chapter 3, I quantify rates of adaptive protein evolution and describe evidence for selective sweeps in RNAi pathway genes using population genomic data from 8 insect and nematode species. These analyses indicate that RNAi genes involved in suppression of transposable elements and defence against viruses evolve rapidly across invertebrates, and I identify genes with signatures of elevated adaptation in multiple insect species. Host genes that underlie host-virus interactions have been described in RNA virus infection of Drosophila, however substantially less attention has focussed on the host response to DNA viruses, primarily because no DNA viruses have been isolated from Drosophila. In Chapter 4, I describe the isolation of Kallithea virus, a Drosophila dsDNA nudivirus, and characterise the host response to infection and genetic variation in resistance. I find that Kallithea virus infection causes early male-specific lethality, a cessation of oogenesis, and induction of undescribed virus-responsive genes. Further, I describe genetic variation in resistance and tolerance to Kallithea virus infection, and identify a potential causal variant for virus-induced mortality in Cip4. Insect viruses commonly encode viral suppressors of RNAi, however there are a multitude of antiviral immune mechanisms besides RNAi which may select for viral-encoded inhibitors. In Chapter 5, I describe the requirement for RNAi and NF-κB in immunity against Kallithea virus, and map gp83 as a virus-encoded inhibitor of NF-κB signalling. I find that gp83 inhibits Toll signalling at the level of, or downstream of NF-κB transcription factors, and that this immunosuppressive function is conserved in other nudiviruses.

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Carissimo, Guillaume. "Caractérisation et rôle de l'immunité antivirale des anophèles dans la compétence vectorielle pour les arbovirus et parasites." Electronic Thesis or Diss., Paris 6, 2014. http://www.theses.fr/2014PA066293.

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Dans une ère où les moustiques modifiés commencent à être utilisés ou envisagés pour contrôler les épidémies de Dengue ou malaria, le manque de connaissance sur l’immunité des insectes vecteurs envers certains pathogènes se fait cruellement ressentir. Pourtant la possibilité de changements de vecteurs, dû à un changement de leur immunité, provoquée par l’Homme est réelle. Pour déterminer la contribution de l’immunité dans différents compartiments du vecteur contre divers pathogènes avons étudié la réponse antivirale dans la première barrière de transmission chez le moustique vecteur de la malaria après une infection par un repas sanguin. Nous montrons que les réponses antivirales sont différentes entre compartiments, et proposons un modèle où des interactions tripartites entre le virus, l’immunité du moustique et la flore entérique interagissent pour contrôler l’infection précoce du moustique après le repas sanguin. De façon surprenante, nous avons également montré que la voie de l’ARN interférence n’a pas d’effet antiviral dans ce compartiment. Nous suggérons que cette voie est utilisée par le parasite Plasmodium pour détourner la réponse antiparasitaire médiée par Toll, grâce à un facteur de virulence de nature ARN double brin. Nous avons également montré que des biais expérimentaux lors de l’infection des insectes ont conduit à l’élaboration d’un dogme disant que la voie de l’ARN interférence est la voie antivirale principale des insectes, mais nos resultats suggèrent que malgré l’importance de cette voie pour controler l’intensité de la réplication virale lors de l’infection disséminée, cette voie n’a aucune fonction antivirale lors de l’infection initiale du tube digestif. Néanmoins, le séquençage des produits de cette voie permet d’assembler de-novo des génomes de virus commensaux. Les résultats de ces travaux montrent très clairement qu’il faut évaluer le rôle et l’impact de toute modification d’insectes vecteurs pour plusieurs classes de pathogènes. Cela ouvre également de nombreux nouveaux champs de recherches et pose de nombreuses nouvelles questions In an era where modified mosquitoes are starting to be used in nature for controlling malaria and Dengue, lack of knowledge about immunity of mosquito vectors to some pathogen classes are becoming more evident. The risks for human-provoked vector shifts of pathogens transmission have not been examined. To fill these gaps, we assessed the antiviral immunity of the malaria vector, Anopheles gambiae, in the strongest mosquito bottleneck for pathogens, the midgut infection barrier after an infective bloodmeal. This work shows that the antiviral responses are different and highly compartmentalized between the midgut and systemic immunity. We propose a model where tripartite interactions between virus, mosquito immunity and enteric flora control early arboviral infection in the midgut. Surprisingly, we showed that while the siRNA pathway had no evident anti-arbovirus activity in the midgut, it was used by Plasmodium to evade mosquito immunity. A virus-like elicitor of double strand RNA nature is transferred from the parasite at the ookinete stage to the mosquito midgut cells, resulting in a shift of immune balance from anti-parasite response to an antiviral-like response. Importantly, our work shows that biases in experimental infection methods led to the misconstruction of a dogma stating that siRNA is the main antiviral pathways in insects, at least in the midgut compartment. And that the use of the pathway products can be successfully used to de-novo assemble previously unknown viruses from the virome. This work indicates that immune modifications in vectors need to be evaluated for changes of vectorial competence to different pathogens. It also opens numerous avenues of research and raises a lot of interesting questions that will need to be investigated in the future

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Carissimo, Guillaume. "Caractérisation et rôle de l'immunité antivirale des anophèles dans la compétence vectorielle pour les arbovirus et parasites." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066293.

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Hauler, Felix. "The ATPase VCP in viral infection and antiviral immunity." Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.707973.

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Schmitt, Éléonore. "Rôle de DICER dans la pathogénèse aux infections par les Herpesviridae." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAJ040.

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Dans les organismes multicellulaires, la régulation de l’expression des gènes par les microARNs est un mécanisme essentiel pour le développement cellulaire et l’homéostasie. De plus, le rôle des microARNs a été démontré dans de nombreux processus immunitaires, tels que l’inflammation. Les virus évoluant conjointement avec leurs hôtes, ils ont appris à détourner la machinerie cellulaire pour leur propre bénéfice. Ainsi, des microARNs codés par certains génomes viraux ont été mis en évidence, mais leurs fonctions, ainsi que leurs cibles, restent encore largement inconnues. En utilisant une lignée de souris présentant une mutation hypomorphe pour le gène dicer, caractérisée par une diminution de la production des microARNs, et son hôte naturel, le cytomégalovirus murin, un virus membre de la famille des β-Herpesvirus, nous avons étudié le rôle potentiel des microARNs d’origine cellulaire et virale dans la pathogénèse de ce virus. Lors de l’infection aigüe, nos résultats montrent un rôle dominant et protecteur des microARNs cellulaires, comparé à celui des microARNs viraux, prédits pour être des facteurs de pathogénicité In multicellular organisms, gene expression regulation by microRNAs is an essential mechanism for cell development and homeostasis. Moreover, several immune-related processes, such as inflammation, have been demonstrated to require specific microRNAs. As viruses have coevolved with their host, they have learned to hijack the cellular defenses for their own benefit. Thus microRNAs-encoding genes were also recently discovered in the genome of Herpesviruses, but up to now, the function and the targets of most microRNAs of viral origin are still largely unknown. Using a hypomorphic mouse mutant line, characterized by a diminished production of microRNAs, and the Mouse Cytomegalovirus, a natural pathogen of mice which belongs to the family of β-Herpesviruses, we investigated the potential roles of microRNAs of both cellular and viral origin in the pathogenesis of this virus. Our results point toward a dominant role of cellular microRNAs as protective factors compared to virally-derived microRNAs which are usually predicted to carry pathogenic functions in acute infections

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Md, Bahanur Rahman. "Studies on the antiviral innate immunity factors in animal serum." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/150096.

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要旨には「Studies on the Antiviral Activity of the Normal Animal Serum」とあり Kyoto University (京都大学) 0048 新制・課程博士 博士(薬学) 甲第9507号 薬博第489号 新制||薬||193(附属図書館) UT51-2002-G265 京都大学大学院薬学研究科生命薬科学専攻 (主査)教授河合明彦, 教授川嵜敏祐, 教授市川厚 学位規則第4条第1項該当

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Legrand, Alexandre. "Evolutionary and functional characterization of SAMD9/SAMD9L innate immunity proteins and their involvement in HIV infection." Electronic Thesis or Diss., Lyon, École normale supérieure, 2024. http://www.theses.fr/2024ENSL0055.

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Le VIH, virus responsable de la pandémie de SIDA, trouve son origine dans des transmissions inter-espèces de lentivirus simiens. Comprendre les interactions moléculaires entre le VIH et la cellule hôte est un objectif majeur pour l’avancée de la lutte contre le VIH/SIDA. En particulier, l’identification de nouveaux acteurs de l’immunité innée contre le VIH participe à la compréhension de son adaptation à l’humain, mais aussi renseigne plus largement sur les stratégies antivirales employées par l’hôte. A cet égard, les gènes SAMD9 et SAMD9L apparaissent comme des candidats d’intérêt. Constituant une famille de gènes impliquée dans des maladies génétiques auto-inflammatoires, SAMD9/9L sont également décrits comme antiviraux contre les poxvirus. De plus, SAMD9L a été identifié dans un criblage comme potentiel inhibiteur du VIH. Cependant, leur rôle et implication vis-à-vis du VIH demeurent inconnus. Ces travaux de thèse révèlent que SAMD9 et SAMD9L ont des effets opposés sur la réplication du VIH, au niveau de la synthèse des protéines virales. Alors que SAMD9 favorise la réplication du VIH-1, SAMD9L exerce une action antivirale souche-spécifique contre les VIH-1, VIH-2 et lentivirus simiens SIV. De plus, nous avons identifié un site nucléasique essentiel pour l’activité antivirale de SAMD9L face au VIH. Ce site actif est également déterminant dans l’activité d’inhibition de traduction cellulaire, en particulier des variants délétères de SAMD9/9L impliqués dans des maladies génétiques sévères. De plus, nos analyses évolutives à partir de séquences et de structures prédites montrent la présence de protéines homologues à SAMD9/9L chez les bactéries, qui seraient également impliquées dans l’immunité antivirale. Malgré une potentielle conservation sur des milliards d’années d’évolution, ces gènes évoluent rapidement au niveau génomique et génétique avec des traces typiques de conflits génétiques au sein des mammifères. Grace à des tests fonctionnels complémentaires, nous avons montré que certaines de ces variations au sein des grands singes constitueraient des adaptations aux lentivirus. En conclusion, ce projet caractérise SAMD9 et SAMD9L comme nouveaux facteurs de l’hôte modulant la réplication du VIH et souligne plus largement leur importance dans l’immunité du vivant Human Immunodeficiency Virus (HIV), agent responsible for the AIDS pandemic, originated from interspecies transmissions of simian lentiviruses. Understanding the molecular interactions between HIV and the host cell is a major objective for advancing the fight against HIV/AIDS. In particular, the identification of new players in innate immunity to HIV not only contributes to our understanding of its adaptation to humans, but also provides broader information on the antiviral defense employed by the host. In this regard, the SAMD9 and SAMD9L genes appear as candidates of interest. Constituting a gene family involved in genetic auto-inflammatory diseases, SAMD9/9L are also described as antiviral against poxviruses. Furthermore, SAMD9L was identified in a screen as a potential HIV inhibitor. However, their role and implication regarding HIV remained unknown. This thesis work reveals that SAMD9 and SAMD9L have opposite effects on HIV replication, at the level of viral protein synthesis. While SAMD9 promotes HIV-1 replication, SAMD9L exerts a strain-specific antiviral action against HIV-1, HIV-2, and simian lentiviruses. In addition, we identified a nuclease site essential for the antiviral activity of SAMD9L against HIV. This active site is also decisive in inhibiting cell translation, in particular of deleterious SAMD9/9L variants implicated in severe genetic diseases. Furthermore, our evolutionary analyzes based on sequences and predicted structures show the presence of homologous proteins to SAMD9/9L in bacteria, which would also be involved in antiviral immunity. Despite a potential conservation over billions of years of evolution, these genes are rapidly evolving at the genomic and genetic levels, with typical traces of host-pathogen genetic conflicts within mammals. Thanks to complementary functional assays, we showed that some of these variations within great apes may be adaptations to lentiviruses. In conclusion, this project discovers and characterizes SAMD9 and SAMD9L as host factors modulating HIV replication and more broadly highlights their importance in living immunity

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Sang, Yongming. "Porcine innate antiviral immunity : host defense peptides and toll-like receptors." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/960.

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Yen, Pei-Shi. "Transgenic mosquitoes for controlling transmission of arboviruses." Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066340.pdf.

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Les arbovirus (virus transmis par des arthropodes) sont à l'origine de maladies humaines telles que la dengue, le chikungunya ou encore le Zika. Le moustique Aedes aegypti, est le vecteur majeur de ces trois arbovirus. La faible efficacité des méthodes de contrôle des populations de moustiques, principalement réalisées au moyen d'insecticides chimiques ouvre un champ de développement de nouvelles approches en lutte antivectorielle. Le moustique, hôte vecteur, contrôle la réplication virale en limitant les réponses immunitaires antivirales. La machinerie RNA interférence (RNAi) est la voie jouant un rôle majeur dans l'immunité antivirale chez le moustique. Alors que le rôle des deux voies, siRNA (" small interfering RNA ") et piRNA (" piwi-interfering RNA "), est de mieux en mieux compris dans les réactions antivirales du vecteur, peu de connaissances sont disponibles à ce jour en ce qui concernent les interactions entre la voie miRNA (" micro RNA ") et les arbovirus. Ainsi, nous proposons une analyse détaillée des mécanismes par lesquels les miARN tentent de réguler la réplication virale chez le moustique. Dans la première partie de la thèse, nous avons effectué une analyse génomique pour identifier les miRNAs pouvant interagir chez Ae. aegypti avec divers lignées/génotypes des virus chikungunya (CHIKV), de dengue (DENV) et de Zika. Avec l'aide d'outils de prédiction faisant appel à divers algorithmes, plusieurs sites de liaison de miARN avec différents lignées/génotypes de chaque arbovirus ont été identifiés. Nous avons ensuite sélectionné les miARN pouvant cibler plus d'un arbovirus et nécessitant un faible seuil d'énergie lors de la formation des complexes entre l'ARNm Mosquito-borne arboviruses cause some of the world’s most devastating diseases and are responsible for recent dengue, chikungunya and Zika pandemics. The yellow-fever mosquito. Aedes aegypti, plays an important role in the transmission of all three viruses. The ineffectiveness of chemical control methods targeting Ae. aegypti makes urgent the need for novel vector-based approaches for controlling these diseases. Mosquitoes control arbovirus replication by triggering immune responses. RNAi machinery is the most significant pathway playing a role on antiviral immunity. Although the role of exogenous siRNA and piRNA pathways in mosquito antiviral immunity is increasingly better understood, there is still little knowledge regarding interactions between the mosquito cellular miRNA pathway and arboviruses. Thus further analysis of mechanisms by which miRNAs may regulate arbovirus replication in mosquitoes is pivotal. In the first part of the thesis, we carried out genomic analysis to identify Ae. aegypti miRNAs that potentially interact with various lineages and genotypes of chikungunya (CHIKV), dengue (DENV) and Zika viruses. By using prediction tools with distinct algorithms, several miRNA binding sites were commonly found within different genotypes/and or lineages of each arbovirus. We further analyzed the miRNAs that could target more than one arbovirus and required a low energy threshold to form miRNA-vRNA (viral RNA) complexes and predicted potential RNA structures using RNAhybrid software. Thus, we predicted miRNA candidates that might participate in regulating arboviral replication in Ae. aegypti. In the second part of the thesis, we developed a miRNA-based approach that results in a dual resistance phenotype in mosquitoes to dengue serotype 3 (DENV-3) and chikungunya (CHIKV) viruses for stopping arboviruses spreading within urban cycles. The target viruses are from two distinct arboviral families and the antiviral mechanism is designed to function through the endogenous miRNA pathway in infected mosquitoes. Ten artificial antiviral 4 miRNAs capable of targeting ~97% of all published strains were designed based on derived consensus sequences of CHIKV and DENV-3. The antiviral miRNA constructs were placed under control of either an Aedes PolyUbiquitin (PUb) or Carboxypeptidase A (AeCPA) gene promoter triggering respectively expression ubiquitously in the transgenic mosquitoes or more locally in the midgut epithelial cells following a blood meal. Challenge experiments using viruses added in blood meals showed subsequent reductions in viral transmission efficiency in the saliva of transgenic mosquitoes as a result of lowered infection rate and dissemination efficiency. Several components of mosquito fitness, including larval development time, larval/pupal mortality, adult lifespan, sex ratio, and male mating competitiveness, were examined: transgenic mosquitoes with the PUb promoter showed minor fitness costs at all developing stages whereas those based on AeCPA exhibited a high fitness cost. Further development of these strains with gene editing tools could make them candidates for releases in population replacement strategies for sustainable control of multiple arbovirus diseases

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Caras, James William. "Emulation and induction of cytotoxic immunity : immunotoxin therapies for AIDS and novel antiviral vaccines /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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Glanz, Anna Nicole. "Regulation of the Antiviral Function of IRF3." University of Toledo Health Science Campus / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=mco1596792904962609.

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Yen, Pei-Shi. "Transgenic mosquitoes for controlling transmission of arboviruses." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066340/document.

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Wang, Ling, Juan Zhao, Junping Ren, et al. "Protein Phosphatase 1 Abrogates IRF7-Mediated Type I IFN Response In Antiviral Immunity." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/6519.

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Interferon (IFN) regulatory factor 7 (IRF7) plays a key role in the production of IFN‐α in response to viral infection, and phosphorylation at IRF7 C‐terminal serine sites is prelude to its function. However, phosphatases that negatively regulate IRF7 phosphorylation and activity have not been reported. In this study, we have identified a conserved protein phosphatase 1 (PP1)‐binding motif in human and mouse IRF7 proteins, and shown that PP1 physically interacts with IRF7. Exogenous expression of PP1 subunits (PP1α, β, or γ) ablates IKKε‐stimulated IRF7 phosphorylation and dramatically attenuates IRF7 transcriptional activity. Inhibition of PP1 activity significantly increases IRF7 phosphorylation and IRF7‐mediated IFN‐α production in response to Newcastle disease virus (NDV) infection or Toll‐like receptor 7 (TLR7) challenge, leading to impaired viral replication. In addition, IFN treatment, TLR challenges and viral infection induce PP1 expression. Our findings disclose for the first time a pivotal role for PP1 in impeding IRF7‐mediated IFN‐α production in host immune responses.

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Wang, Ling, and Shunbin Ning. "Protein Phosphatase 1 Abrogates IRF7-Mediated type I IFN Response in Antiviral Immunity." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/6545.

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Lietke, Debra Stefanie [Verfasser], and Simon [Akademischer Betreuer] Rothenfußer. "CRIF1 and its function in antiviral immunity / Debra Stefanie Lietke ; Betreuer: Simon Rothenfußer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1135136033/34.

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West, Cara C. "Antiviral Immune Responses to Invertebrate Iridescent Virus 6 in Drosophila." eScholarship@UMMS, 2018. https://escholarship.umassmed.edu/gsbs_diss/953.

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The innate immune system is a critical first line of defense against invading pathogens. Innate immunity directly detects pathogens, sets up an appropriate adaptive response, and can directly kill pathogens. Drosophila may lack an adaptive immune response, but have a robust innate immune system with a variety of defense effector mechanisms. While the responses to bacteria, fungi, and RNA viruses have been well characterized, not much is known about the response to DNA viruses. My studies have set out to characterize the Drosophila immune response to a DNA virus, utilizing the large dsDNA virus, Invertebrate Iridescent Virus 6 (IIV-6). IIV-6 infection causes shortened lifespan, and in later stages of infection, flies present with abdominal swelling and iridescent blue color. Our objectives were to identify pathways flies use to protect themselves from IIV-6 infection, determine how this protection is mediated, and to identify any immune inhibitors that IIV-6 uses to suppress innate immune signaling. I have found that IIV-6 strongly up-regulates a class of stress proteins with unknown function, termed Turandots, after infection in vivo or in vitro. This induction is dependent upon viral replication, requires JAK-STAT activation, and activation of p38b MAPK. In addition, the unpaireds, which function as JAK-STAT ligands, are upregulated after IIV-6 infection in a p38b-dependent manner. Together, this data suggests that p38b activation leads to production of unpaired cytokines and activation of JAK-STAT signaling to induce Turandots. I have also found that IIV-6 infected cells secrete protective factors. This response is induced within 12 hours of IIV-6 infection, exosome-mediated, and provides robust protection to naive cells challenged with an mCherry-expressing strain of IIV-6. Additionally, IIV-6 inhibits two major immune responses in Drosophila, the IMD and Toll pathways. Stimulation of IIV-6 infected Drosophila S2* cells with either IMD or Toll stimulators results in very poor antimicrobial peptide responses. Yet, IMD and Relish are still cleaved upon stimulation in IIV-6 infected cells, indicating that the block is downstream. In support of this finding, IIV-6 infected flies respond very poorly to infection with the enterobacteria Erwinia carotovora carotovora compared to mock-injected flies.

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Ribeiro, Palha Nuno Miguel. "To the origins of vertebrate antiviral immunity : imaging host-virus interactions in the zebrafish." Paris 6, 2013. http://www.theses.fr/2013PA066423.

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L’objectif principal de ce travail a été de mieux comprendre la réponse immunitaire antivirale innée du poisson zèbre (Danio rerio). Unique parmi tous les modèles de recherche vertébrés, la larve de ce poisson rend possible l’imagerie in vivo non invasive des infections au niveau de l’organisme entier. Nous avons développé et caractérisé deux modèles d’infection virale complémentaires chez la larve du poisson zèbre : l��une est fatale pour les animaux infectés, l’autre induit une réponse interféron (IFN) protectrice. Le premier modèle se base sur l’utilisation du virus de la nécrose hématopoïétique infectieuse (IHNV), un rhabdovirus qui entraîne d’importantes pertes en aquaculture. Nous avons démontré que les cellules endothéliales étaient les premières cibles de ce virus, ce qui explique les hémorragies qui en découlent. Par ailleurs, nous avons identifié le moment critique où la pathogenèse virale devient irréversible. Cet évènement a lieu avant le déclenchement de la réponse immunitaire. La mise au point d’un nouveau modèle d'infection par un virus Chikungunya (CHIKV) fluorescent a quant à lui permis de suivre en temps réel l’infection. Nous avons quantifié l’apparition et la mort des cellules infectées, ce qui a montré que leur survie varie en fonction de leur type cellulaire. Cela explique que le virus soit seulement détecté dans le parenchyme du cerveau aux états les plus tardifs de l’infection. Étonnamment, les neutrophiles sont une source principale d’interféron et ont un rôle protecteur contre l’infection. Nos résultats démontrent également un rôle crucial de la détection cytoplasmique de CHIKV et suggèrent une redondance des deux groupes d’IFNs de type I présents chez le poisson zèbre dans le contrôle de cette infection. Dans l'ensemble, cette étude approfondit significativement la connaissance sur les réponses antivirales du poisson zèbre. Elle fournit des informations clés pour l’utilisation future de ce modèle pour cribler et caractériser respectivement des molécules et des gènes antiviraux The aim of this thesis was to further understand the core vertebrate innate antiviral immune response through analysis of viral infections in the zebrafish (Danio rerio) system. Unique among all vertebrate models, the zebrafish larva renders possible non-invasive imaging of infections at the whole organism level. We have developed and characterized two complementary viral infection models in the zebrafish larva: one with a virus that invariably kills infected fish, and another where the virus elicits a potent, protective host interferon (IFN) response. The first model is the zebrafish infection with the important aquaculture rhabdovirus IHNV (Infectious Hematopoietic Necrosis Virus). We found that endothelial cells were the first targets of this virus, explaining the consequent ensuing hemorrhages. We identified the critical moment when pathogenesis becomes irreversible, which happens long before the onset of the immune response. The second is a new CHIKV (Chikungunya virus) infection model. Time-lapse imaging analysis of the kinetics of appearance and death of infected cells revealed organ-specific differences in CHIKV-infected cell survival, a feature responsible for later restriction of the virus to the brain parenchyma. Surprisingly, we identified neutrophils as a key cell population producing IFN and controlling the infection in zebrafish. Our results also support a crucial role for cytoplasmic virus sensing pathways and show redundancy of zebrafish group I and group II type I IFNs in CHIKV infection control. Overall, this study provides significant insight into zebrafish innate antiviral responses and provides key information for the future use of zebrafish as a new model to screen for and characterize antiviral genes and drugs

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Castanier, Céline. "Étude de la régulation de la protéine mitochondriale MAVS au cours de l’immunité innée antivirale." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA11T046.

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L’immunité innée représente la première ligne de défense d’un organisme face à une infection virale, en engendrant une réponse rapide capable de restreindre la menace microbienne. Dans la cellule, les récepteurs Toll-likes (TLRs) et les hélicases cytosoliques RIG-I like (RLRs) représentent les deux systèmes majeurs de reconnaissance des virus. Les acides nucléiques viraux sont notamment reconnus les hélicases cytosoliques RIG-I et MDA5. Ces deux protéines possèdent deux domaines CARD impliqués dans le recrutement de la protéine adaptatrice MAVS, capable d’induire l’activation des promoteurs interférons (IFNs) de type I et de NF-B pour la mise en place d’une réponse antivirale. De façon surprenante, MAVS est localisée au niveau de la mitochondrie et a besoin de cette association au compartiment mitochondrial pour exercer sa fonction. Bien que de nombreuses études aient montré le rôle crucial de la protéine mitochondriale MAVS dans la signalisation antivirale des RLRs, sa régulation est encore mal connue à ce jour. Ce travail de doctorat a permis de mettre en évidence que la dégradation de MAVS suite à une infection virale est nécessaire à la transduction du signal antiviral. Nous avons ainsi déterminé que l’E3 ubiquitine ligase TRIM25 induit l’ubiquitination puis la dégradation de MAVS quelques heures après une infection virale. De plus, nous avons montré que l’activation du signalosome aboutissant à la production des IFNs de type I et dépendant de MAVS n’a lieu que suite à sa translocation de la mitochondrie vers le cytosol permise par la dégradation de MAVS. Enfin, nous avons mis en évidence le rôle essentiel de l’élongation du réseau mitochondrial suite à une infection virale pour la transduction du signal dépendant de MAVS Innate Immunity acts as the first line of the host defense against viral infection, providing a rapid response to restrict the microbial threats. Toll-like receptors (TLRs) and cytosolic RIG-I-like helicases (RLRs) are the two major receptor systems for detecting virus. Viral nucleic acids are recognised by the helicases RIG-I and MDA5. These receptors contain two CARD domains involve in the recruitment of the mitochondrial antiviral signaling adaptor MAVS whose activation triggers a rapid production of type 1 interferons (IFNs) and of pro-inflammatory cytokines. Interestingly, it has been reported that MAVS must be localized to mitochondria to exert its function. While MAVS is essential for this signaling, its function and regulation remain unclear. In this work, we report that RLR activation triggers MAVS ubiquitination by the E3 ubiquitin ligase TRIM25 and marks it for proteasomal degradation concomitantly with downstream signaling. MAVS appears to function as a recruitment platform to first assemble a signaling complex, then the proteasome-mediated MAVS degradation is required to unleash into the cytosol this signaling complex allowing the signalosome activation and ensuing type I IFNs production. Futhermore, we reported that mitochondrial dynamics regulate MAVS-mediated signaling after viral infection

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Rodriguez, Julio. "Semliki Forest virus infection of mosquito cells : novel insights into host responses and antiviral immunity." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8063.

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Arboviruses are transmitted between vertebrate hosts by arthropod vectors, such as mosquitoes or ticks. In vertebrates arboviruses cause cytopathic effects and disease, however, arbovirus infection of arthropods usually results in persistence. Control of arboviral infection is mediated by the arthropod’s immune system. Pathways such as RNAi, JAK/STAT, Toll and IMD have previously been implicated in controlling arbovirus infections. In contrast, the antiviral role of other pathways in mosquitoes, such as melanisation, is unknown. Using high through output 454 sequencing the transcriptome of U4.4 cells infected with the model arbovirus Semliki Forest virus (SFV)(Togaviridae, Alphavirus) was generated. This experiment revealed intriguing patterns of differential transcript abundance that suggest a broad impact of SFV infection in U4.4 cells, such as in metabolism, cell structure and nucleic acid processing. SFV infection induces differential expression of genes in pathways such as apoptosis, stress response and cell cycle. Most interestingly, this study indicated that melanisation might have an antiviral role in mosquitoes. In arthropods, melanisation is a process involved in wound healing and antimicrobial defences. Phenoloxidase (PO), a key enzyme involved in melanisation, is cytotoxic and therefore kept in its inactive form, prophenoloxidase (PPO), until activation is triggered. The PPO activation process is tightly regulated by serine protease inhibitors (serpins) which inhibit the proteolytic activation reaction. In this thesis I demonstrate that the supernatant of cultured Aedes albopictus-derived U4.4 cells contains a functional proPO-activating system, which is activated by infection with bacteria and virions of SFV. Activation of this pathway reduces the spread and infectivity of SFV in vitro and in vivo. In order to further characterise the PO cascade and its antiviral role the serpins in Ae. albopictus were also investigated. Using the transcriptome sequencing and bioinformatics we identified and classified 11 serpins. We silenced each of the serpins and monitored PPO levels and antiviral activity showing that homologues to drosophila’s serpin- 27a plays a role in melanisation against SFV in vitro. Collectively, these results characterise the mosquito PO cascade as a novel immune defence against arbovirus infection in mosquitoes.

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Rückert, Claudia. "Alphavirus and flavivirus infection of Ixodes tick cell lines : an insight into tick antiviral immunity." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/10063.

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Arthropod-borne viruses, arboviruses, have the ability to replicate in both vertebrates and invertebrates and are transmitted to susceptible vertebrate hosts by vectors such as mosquitoes and ticks. Ticks are important vectors of many highly pathogenic arboviruses, including the flavivirus tick-borne encephalitis virus (TBEV) and the nairovirus Crimean-Congo haemorrhagic fever virus. In contrast, alphaviruses are principally mosquito-borne and have been isolated only rarely from ticks; ticks have not been implicated as their vectors. Nevertheless, the alphavirus Semliki Forest virus (SFV) replicates in cell lines derived from many different tick species, including those of the genus Ixodes, which includes vectors of TBEV and its lesspathogenic relative Langat virus (LGTV). In vertebrate cells, arboviruses generally cause cytopathic effects; however, arbovirus infection of arthropod cells usually results in a persistent low-level infection without cell death. While little is known about antiviral immunity in tick cells, the immune system of other arbovirus vectors such as mosquitoes has been studied extensively over the last decade. In insects, pathways such as RNA interference (RNAi), JAK/STAT, Toll, Imd and melanisation have been implicated in controlling arbovirus infection, with RNAi being considered the most important antiviral mechanism. In tick cells, RNAi has been shown to have an antiviral effect, but current knowledge of other immunity pathways is limited and none have been implicated in the antiviral response. In the present study, SFV and LGTV replication in selected Ixodes spp. tick cell lines was characterised and the Ixodes scapularis-derived cell line IDE8 was identified as a suitable cell line for this project. Potential antiviral innate immunity pathways were investigated; putative components of the tick JAK/STAT, Toll and Imd pathways were identified by BLAST search using available sequences from well-studied arthropods including the fruit fly Drosophila melanogaster. Using gene silencing, an attempt was made to determine whether these pathways play a role in controlling SFV and LGTV infection in tick cell lines. Selected genes were silenced in IDE8 cells using long target-specific dsRNA and cells were subsequently infected with either SFV or LGTV. Effects of gene silencing on virus replication were assessed by quantitative real time PCR (qPCR) or luciferase reporter assay. Effects on infectious virus production were measured by plaque assay. Replication of the orbivirus St Croix River virus (SCRV), which chronically infects IDE8 cells, was also quantified by qPCR after silencing of selected genes. Interestingly, SFV or LGTV infection of IDE8 cells resulted in a significant increase in SCRV replication, possibly as a result of interference with antiviral pathways by SFV and LGTV or possibly due to diversion of cellular responses from sole control of SCRV. No evidence for an antiviral role for the JAK/STAT or Toll pathways was found in IDE8 cells. However, an antiviral effect was observed for protein orthologues putatively involved in the RNAi response. Argonaute proteins play an important role in translation inhibition and target degradation mediated by RNAi, and silencing of selected Argonaute proteins resulted in a significant increase in SFV and SCRV replication. The carboxypeptidase CG4572 is essential for an efficient antiviral response in D. melanogaster, and supposedly involved in the systemic RNAi response. A putative tick orthologue of CG4572 was identified and this appeared to be involved in the antiviral response in IDE8 tick cells. When expression of CG4572 was silenced and cells subsequently infected with SFV or LGTV, replication of both viruses was significantly increased. In addition, it was shown that three mosquito orthologues of CG4572 also had an antiviral role against SFV in Aedes mosquito cells. In conclusion, of the tick cell lines investigated, IDE8 provided a suitable model system for investigating tick cell responses against arboviruses and new insight into the nature of the tick cell antiviral response was gained.

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Guedes, Mariana da Rocha Soares. "Mitochondria and peroxisomes : role within cellular antiviral defense." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/12960.

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Mestrado em Biomedicina Molecular The present paper presents a review and compilation of all the scientifically relevant bibliography to date, regarding the antiviral signalling pathways implicated in the cellular innate immune system in humans. Emphasizing the mitochondrial antiviral signalling adaptor (MAVS), this paper explores the special features of the signal transduction pathways and their components in two specific organelles: mitochondria and peroxisomes. These pathways, ultimately, result in the expression of interferon-stimulated genes (ISGs), which are primarily responsible for fighting against viral replication, viral particle assembly and virion release within the cell. In this paper, several proposals for further investigation are also presented, since there is still a lot to learn about the role of peroxisomes in the antiviral innate immune responses. O presente trabalho propõe-se a rever e compilar toda a bibliografia cientificamente relevante até à data, no que respeita as vias de sinalização antivirais implicadas na imunidade celular inata em células humanas. Com ênfase na proteína adaptadora MAVS, este trabalho explora as particularidades das vias de transdução de sinal e respetivos intervenientes em dois organelos celulares específicos: mitocôndrias e peroxissomas. Estas vias, em última instância, resultam na expressão de genes estimulados por interferões (ISGs), principais responsáveis pelo combate celular eficaz contra a replicação viral, montagem de partículas virais e libertação de viriões na célula infetada. Neste trabalho são ainda apresentadas propostas para investigações futuras, uma vez que ainda muito pouco se sabe sobre o papel dos peroxissomas nas respostas imunitárias inatas contra infeções virais.

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Lafont, Maxime. "Mécanismes et spécificité du priming immunitaire antiviral chez un Lophotrochozoaire, l'huitre creuse Crassostrea gigas." Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0041/document.

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Depuis 2008, des épisodes de surmortalité massive d’origine multifactorielle, affectent mondialement les élevages de juvéniles d’huître creuse Crassostrea gigas dont le virus de type herpès, l’OsHV-1, peut être considéré comme un des agents pathogènes majeurs. L’immunité des huîtres, repose sur un système immunitaire inné et a longtemps été considéré comme peu spécifique et dépourvu de mémoire. Cependant, cette vision a été remise en question via des études ayant démontré l’existence d’une réponse immunitaire spécifique et mémoire chez des invertébrés. Dans le cadre de cette thèse, l’objectif était de caractériser le priming immunitaire antiviral ainsi que ses mécanismes chez l’huître face au virus OsHV-1. En stimulant les huîtres avec un agent mimétique viral, le poly(I:C), nos travaux ont montré que cette molécule protégeait spécifiquement contre l’OsHV-1 en milieu contrôlé et en milieu naturel sur le long terme, en améliorant le taux de survie des huîtres de près de 100%, mais pas d’infections bactériennes. Une approche RNA-seq nous a permis d’identifier différentes voies de signalisations immunitaires antivirales régulées suite à la stimulation par le poly(I:C). Les profils de régulation sont majoritairement maintenus dans le temps (au moins 10 jours), ce qui pourrait expliquer la protection observée. L’ensemble de ces résultats montre l’existence d’un phénomène de priming immunitaire antiviral efficace chez un Lophotrochozoaire et apporte une contribution à la compréhension des mécanismes moléculaires sous-jacents à ce phénomène. Ces travaux ont permis d’apporter des pistes de sortie de crise pour la filière ostréicole jusqu’alors inexplorées Since 2008, mass mortality events of multifactorial origin have affected the Pacific oyster Crassostrea gigas farms worldwide, in which a herpesvirus, the OsHV-1, can be considered as one of the major pathogens. The immunity of oysters, as for all invertebrates, is based on an innate immune system that has long been considered to be scarcely specific and to lack memory. However, in recent years this simplistic view has been questioned through studies that have demonstrated the existence of a specific immune response and memory. However, knowledge about the mechanisms underlying these phenomena still remains extremely fragmentary. The aim of this thesis was to characterize the antiviral immune priming and its mechanisms in the oyster against OsHV-1. By stimulating oysters with a viral mimic, poly(I:C), we have shown that this molecule specifically protects against OsHV-1 in controlled environment and in natural environment, protecting oysters from mass mortality events on the long term (min. 5 months) by improving oyster survival by almost 100% but does not protect against bacterial infection. A RNA-seq approach carried out during this thesis allowed us to identify different antiviral immune pathways regulated following the stimulation by poly(I:C). The regulation profiles are mostly maintained over time (at least 10 days), which could explain the observed protection. All these results show the existence of an effective antiviral immune priming phenomenon in a Lophotrochozoan and contribute to the understanding of the molecular mechanisms underlying this phenomenon. This work opens new perspectives hitherto unexplored to support oyster farming against this crisis

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Le, Van Tuan. "Establishment of a memory B cell assay using recombinant Flavivirus protein for determinant of specific antiviral immunity." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-151733.

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Tick-borne encephalitis virus (TBEV) is a serious viral infection that affects the central nervous system. It was estimated that between 1990 and 2009 a total of 169,937 cases of TBE were recorded in Europe. TBEV belongs to genus Flavivirus that comprises over 70 viruses, many of them are important human pathogens. Most members are either transmitted by mosquitoes e.g. West Nile virus (WNV), Dengue virus (DENV) or ticks e.g. TBEV. Due to the extensive antigenic cross-reactivity among flaviviruses serological diagnosis of TBE infections is commonly difficult in areas where more than one virus type circulates. Particularly, a situation now exists in Europe, where TBEV and WNV are endemic in many countries Thus, this thesis focused on the one hand on optimization of serological test systems using recombinant envelope protein domain III (rED3). It represents domain 3 of the major antigen, the surface protein E, which additionally has been shown to induce flavivirus specific neutralizing antibodies. Therefore rED3 was expressed and purified and its application as antigen in ELISA for TBEV diagnosis was verified. On the other hand a memory B-cell assay was established to analyse antiviral immunity after TBEV-vaccination. Here rED3 was used as antigen to determine the frequency of rED3 specific antibody-secreting cells (ASCs). Vaccination is the most effective method of preventing TBE disease and is currently recommended for all those who live and work or travel to areas of TBE endemicity. An essential requirement of any vaccine is the induction of long-term protective immunity. Several vaccines have deﬁned levels of serum antibody (as measured by ELISA, haemagglutination inhibition test, or neutralisation test) that serve as correlates or surrogates of protective immunity. But this does not take account of vaccine induced memory B cells. Although, not providing direct protection against infection, they represent an important second line of immune defence that is initiated only if pre existing antibody levels are too low to prevent infection or if the invading pathogen is able to circumvent the pre-existing antibody response. A thorough understanding of the frequencies of antigen-speciﬁc memory B cells and their relationship with the antibodies in serum serological memory is likely to be critical to give information about the long-term efficacy of vaccine as well as its correlates of protection. This thesis focuses on the establishment of a recombinant protein based ELISA and of a memory B cell assay for analysis of specific antiviral immunity after vaccination with the following two objectives: (1) Expression and purification of recombinant envelope protein domain 3 (rED3) and verification of its application as antigen in ELISA for TBEV diagnosis; (2) Establishment of a memory B cells assay using rED3 for determination of frequency of rED3 specific antibody-secreting cells (ASCs) in individuals vaccinated against TBE. In this study, TBEV- and WNV-speciﬁc antigen ED3 was expressed in E. coli as MBP fusion proteins with C-terminal histidine tag using pMAL-c2x vector. By purification with amylose affinity chromatography followed by nickel affinity chromatography, highly purified TBEV rED3 and WNV-rED3 were obtained. Nevertheless, using TBEV-rED3 protein in Western Blot unspecific reaction with serum antibodies of negative serum was detected and a differentiation between WNV infection and TBEV was impossible, probably due to the MBP moiety. However, using the purified rED3 protein as antigen in ELISA, TBE virus-speciﬁc antibodies were detected specifically. Twenty-three serum samples predefined as TBEV positive were tested positive by rED3-based ELISA and commercial IgG ELISA. Five predefined negative serum samples were tested negative by rED3-based IgG ELISA as well as commercial IgG ELISA. But cross reactivity of WNV and DENV positive sera was detected in 15 of 18 sera by commercial ELISA. On the other hand, these samples were found negative in TBEV rED3-based ELISA. Thus, TBEV-rED3-based ELISA allows a differentiation of infections caused by TBE serogroup and mosquito-borne flaviviruses but not the inactivated virus based commercial ELISA. Interestingly, compared to neutralisation test the specificity of rED3-based ELISA obtained 100% with a sensitivity of 91.6%. In contrast, the commercial ELISA obtained 100 % sensitivity but a low specificity with only 42.8%. In order to determine frequency of antigen-specific antibody secreting cells (ASCs) produced by individuals who received the vaccination against TBE, peripheral blood mononuclear cells (PBMCs) were isolated from blood samples. Subsequently, memory B cells were activated with R848 (Resiquimod) and human recombinant IL-2 (hrIL-2) for 72 hours in 37°C, 5% CO2, 90% humidity. After 72 hours of incubation, Enzyme-Linked Immunospot (ELISPOT) detected antigen-specific memory B cells. In order to evaluate specificity of TBEV-rED3 in ELISPOT, other antigens including WNV-rED3, Maltose binding protein (MBP) and Influenza Nucleoprotein (NP) were included. Study subjects could be separated into two groups: last vaccination before 5 years or longer than 10 years. TBEV-rED3 speciﬁc ASCs could be detected in 11 of 12 TBE vaccinated individuals with different vaccination history and even low serum anti-TBE antibodies levels. TBEV-rED3 specific ASCs were found with frequency of ranging 0.016-0.188 % per total IgG ASCs and lower than frequency of Influenza-NP specific ASCs (between 0.012-0.51%). But TBE-specific memory B cells could be maintained for more than 20 years of post-vaccination. There was a significant difference in number of ASCs between vaccinated and non-vaccinated group (p<0.05). Interestingly, there was no significant difference between TBE vaccinated groups between 1-5 years (mean of 2.5 years) and >10 years (mean of 16.5 years) since vaccination (p>0.05). These finding proved that memory B cells have been stable for years and are maintained up to 25 years since last vaccination. A statistic analysis showed that there was no signiﬁcant correlation between serum levels of anti-TBEV antibodies and the frequency of rED3 specific IgG ASCs (p>0.05, Spearman’s coefficient r = 0.36). A similar result was also indicated for influenza-vaccinated individuals (p>0.05, Spearman’s coefficient r = 0.27). These findings revealed that memory B cells and plasma cells maybe play an independently role in maintaining of immunological memory. Anyway, neutralizing antibodies have been found in all vaccines (a Geometric mean titre (GMT) of 96.04, 95% confident interval (CI): 52.76-174.8) and thus were maintained for a long time since last vaccination. Interestingly, the quantitative determination of specific IgG in TBE post-vaccination sera by rED3-based ELISA exhibits a good correlation with neutralizing antibody titres. The presence of specific antibodies in rED3-based ELISA is therefore highly predictive for the presence of neutralizing antibodies, and this correlation can probably be used in the future to establish guidelines for recommendations of booster vaccinations. Additionally, it became apparent that the number of previous booster vaccinations correlated strongly with the frequency of circulating memory B cells. As expected, individuals who received a booster increased both the specific antibody titre and frequency of antigen specific memory B cells. This suggests that immunological long-term memory induced by booster immunizations is better reflected by the circulating memory B cells than the amount of the antibody titre. Thus, memory B cells seem to be a more reliable parameter for the assessment of long-term immunity. Taken together, a highly antigenic rED3 using the bacterial expression system was produced and it is a promising alternative to whole inactivated virus in ELISA. Notably, rED3 was a reliable antigen for detecting antigen-specific memory B cells in individuals who have been previously TBEV vaccinated. This study provides data on immunological memory for TBE vaccination and might be useful for reconsideration of recommendations for booster dose. In conclusion, boosters of vaccination should be recommended for all individuals who live and work or travel to areas of TBE endemicity. As consequently, vaccine-induced protection is enhanced by both strong humoral and cell-mediated immune responses. If pace of pathogenesis is rapidly growing, pre-existing virus-specific antibodies represent the first line of defence against infection before the memory response is fully activated and implemented. They clearly function best together to efficiently protect against disease.

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Kim, Mi Young. "HSP70 AND A NOVEL AXIS OF TYPE I INTERFERON-DEPENDENT ANTIVIRAL IMMUNITY IN THE VIRUS-INFECTED BRAIN." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1374138000.

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Yoo, Ji Seung. "INVESTIGATIONS INTO THE ROLES OF PKR-INDUCED ANTIVIRAL STRESS GRANULE AND DHX36 IN RIG-I SIGNALING." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/189378.

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Oh, Seong-Wook. "Functional Analysis of RIG-I and RNP Complexes in the Antiviral Interferon System." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215973.

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Lee, Min-Hi. "Induction and regulation of antiviral defence mechanisms through intracytoplasmic sensors." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15950.

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Das Wechselspiel zwischen Viren und ihren Wirtszellen beginnt meist an pattern recognition-Rezeptoren (PRRs), die für die Erkennung unterschiedlichster Pathogene anhand bestimmter Strukturen, sogenannten pathogen-associated molecular patterns (PAMPs), zuständig sind. Nach Detektion lösen die PRRs über verschiedene Signalkaskaden eine antivirale Antwort aus, die zur Expression antiviraler Gene führt. RIG-I und MDA5 sind zytoplasmatisch lokalisierte PRRs und erkennen RNA-Strukturen, die insbesondere während der viralen Replikation und Transkription verfügbar sind. Hantaviren sind humanpathogene RNA-Viren mit einem einzelsträngigen, segmentierten Genom. Die Konsequenzen hantaviraler Infektionen auf molekularer Ebene wurden bereits detailliert untersucht, aber die Mechanismen, die zur Induktion der Immunantwort führen, wie auch mögliche Immunevasionsstrategien, die wahrscheinlich in Zusammenhang mit der Pathogenität des jeweiligen Hantavirusstamms variieren, konnten bisher nicht identifiziert werden. Da Hantaviren im Cytoplasma ihrer Wirtszellen replizieren, stellen RIG-I und MDA5 potentielle Detektoren dar. In dieser Doktorarbeit wird die Bedeutung von RIG-I und MDA5 für die Erkennung von Hantavirus-Infektionen untersucht. Wachstumskinetiken zeigten, daß RIG-I die Replikation von pathogenen wie auch apathogenen Hantaviren beeinträchtigt. Außerdem konnte die RNA hantaviraler Nukleocapsid- (N-) ORFs als eine virale Komponente identifiziert werden, die Typ I Interferon über RIG-I induziert. Das Ausmaß der Interferon-Aktivierung korrelierte hierbei tendenziell mit dem Virulenzgrad der Virusstämme und war für die nicht-pathogenen Hantaviren nicht nachweisbar. Unterschiede in der Aktivierungsstärke können anhand vorläufiger Daten wahrscheinlich auf noch nicht identifizierte Motive zurückgeführt werden, die am 3’-Ende der N ORFs liegen. Im Gegensatz dazu wurde keine Interferon-Aktivierung durch hantavirale Komponenten über MDA5 festgestellt. Host-virus interaction is usually initated by pattern recognition receptors (PRRs) which are responsible for the recognition of various pathogens based on so-called pathogen-associated molecular patterns (PAMPs). Upon detection, PRRs trigger an antiviral immune response through different signalling cascades that lead to the expression of antiviral genes including interferon genes. RIG-I and MDA5 are cytoplasmically localised PRRs and recognise RNA patterns that are particularly available during viral replication and transcription. Hantaviruses are RNA viruses with single-stranded segmented genomes. The consequences of hantaviral infections have been analysed in detail, but the mechanisms that lead to the induction of the innate immune response as well as immune evasion strategies depending on the pathogenicity of the respective hantavirus strains have not been identified yet. Since hantaviruses replicate in the cytoplasm of their host cells, RIG-I and MDA5 represent potential PRRs for hantaviral detection. This thesis investigates the impact of RIG-I and MDA5 on recognition of hantaviral infections. Growth kinetics show that RIG-I impairs the replication of pathogenic as well as non-pathogenic hantaviruses. Furthermore, the RNA of hantaviral nucleocapsid protein (N) ORF could be identified as a viral component responsible for the induction of RIG-I signalling. It is shown that the degree of interferon promotor activation correlates with the virulence of the hantavirus strain from which the N ORF was derived. Based on preliminary data, differences in activation strength may be attributed to not yet identified motifs at the 3’ end of the ORF. In contrast, no interferon activation through MDA5 could be observed.

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Liu, Qinfang. "Interaction of type I interferons and mTOR signaling underlying PRRSV infection." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32860.

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Master of Science in Biomedical Sciences Department of Anatomy and Physiology Yongming Sang Animal metabolic and immune systems integrate and inter-regulate to exert effective immune responses to distinct pathogens. The signaling pathway mediated by mechanistic target of rapamycin (mTOR) is critical in cellular metabolism and implicated in host antiviral responses. Recent studies highlight the significance of the mTOR signaling pathway in the interferon (IFN) response. Type I IFNs mediate host defense, particularly, against viral infections, and have myriad roles in antiviral innate and adaptive immunity. In addition to their well-known antiviral properties, type I IFNs also affect host metabolism. However, little is known about how animal type I IFN signaling coordinates immunometabolic reactions during antiviral defense. Therefore, understanding the interaction of mTOR signaling and the type I IFN system becomes increasingly important in potentiating antiviral immunity. Tissue macrophages (MФs) are a primary IFN producer during viral infection, and their polarization to different activation statuses is critical for regulation of immune and metabolic homeostasis. Using porcine reproductive and respiratory syndrome virus (PRRSV) as a model, we found that genes in the mTOR signaling pathway were regulated differently in PRRSV-infected porcine alveolar MФs at different activation statuses. Therefore we hypothesize that: 1) the mTOR signaling pathway involves host anti-PRRSV regulation; 2) mTOR signaling interacts with IFN signaling to modulate the antiviral response; and 3) different type I IFN subtypes (such as IFN-α1 and IFN-β) regulate mTOR signaling differently. We show that modulation of mTOR signaling regulated PRRSV infection in MARC-145 cells and porcine primary cells, in part, through regulating production and signaling of type I IFNs. In addition, expression and phosphorylation of two key components in the mTOR signaling pathway, AKT and p70 S6 kinase, were regulated by type I IFNs and PRRSV infection. Taken together, we determined that the mTOR signaling pathway, a key pathway in regulation of cell metabolism, also mediates the type I IFN response, a key immune response in PRRSV infection. Our findings reveal that the mTOR signaling pathway potentially has a bi-directional loop with the type I IFN system and implies that some components in the mTOR signaling pathway can serve as targets for augmentation of antiviral immunity and therapeutic designs.

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O'Neal, Scott Thomas. "The role of ATP-sensitive inwardly rectifying potassium channels in the honey bee (Apis mellifera L.)." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78344.

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Honey bees are economically important pollinators of a wide variety of crops that have attracted the attention of both researchers and the public alike due to unusual declines in the numbers of managed colonies in some parts of the world. Viral infections are thought to be a significant factor contributing to these declines, along with exposure to agricultural and apicultural pesticides, but viruses have proven a challenging pathogen to study in a bee model and interactions between viruses and the bee antiviral immune response remain poorly understood. Recent studies have demonstrated an important role for inwardly-rectifying ATP-sensitive potassium (KATP) channels in the cardiac regulation of the fruit fly antiviral immune response, but no information is available on their role in the heart-specific regulation of bee immunity. The results of this work demonstrate that KATP channel modulators have an observable effect on honey bee heart rate that supports their expected physiological role in bee cardiac function. Here, it is also reported that the entomopathogenic flock house virus (FHV) infects adult bees, causing rapid onset of mortality and accumulation of viral RNA. Furthermore, infection-mediated mortality can be altered by pre-exposure to KATP channel modulators. Finally, this work shows that exposure to environmental stressors such as commonly used in-hive acaricides can impact bee cardiac physiology and tolerance to viral infection. These results suggest that KATP channels provide a significant link between cellular metabolism and the antiviral immune response in bees and highlight the significant impact of environmental stressors on pollinator health. Ph. D.

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Falconer, Karolin. "HIV-1/HCV co-infection immunity and viral dynamics /." Stockholm, 2010. http://diss.kib.ki.se/2010/978-91-7409-762-7/.

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Gallagher, Glen R. "Viruses Implicated in the Initiation of Type 1 Diabetes Affect β Cell Function and Antiviral Innate Immune Responses: A Dissertation". eScholarship@UMMS, 2016. https://escholarship.umassmed.edu/gsbs_diss/856.

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The increasing healthcare burden of type 1 diabetes (T1D) makes finding preventive or therapeutic strategies a global priority. This chronic disease is characterized by the autoimmune destruction of the insulin-producing β cells. This destruction leads to poorly controlled blood glucose and accompanying life threatening acute and chronic complications. The role of viral infections as initiating factors for T1D is probable, but contentious. Therefore, my goal is to better characterize the effects of viral infection on human β cells in their function of producing insulin and to define innate immune gene responses in β cells upon viral infection. These aspects were evaluated in various platforms including mice engrafted with primary human islets, cultured primary human islets, β cells derived from human stem cells, and a human β cell line. Furthermore, the contributions of cell-type specific innate immune responses are evaluated in flow cytometry-sorted primary human islet cells. Taken together, the results from these studies provide insights into the mechanisms of the loss of insulin production in β cells during virus infection, and characterize the antiviral innate immune responses that may contribute to the autoimmune destruction of these cells in T1D.

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Gallagher, Glen R. "Viruses Implicated in the Initiation of Type 1 Diabetes Affect β Cell Function and Antiviral Innate Immune Responses: A Dissertation". eScholarship@UMMS, 2006. http://escholarship.umassmed.edu/gsbs_diss/856.

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Chesarino, Nicholas M. "Defining the Biochemical Factors Regulating IFITM3-Mediated Antiviral Activity." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480426112676394.

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McNally, Beth Anne. "A role for cytoplasmic PML in the cellular antiviral response." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133377007.

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Chen, Hong. "Activation and Role of Memory CD8 T Cells in Heterologous Antiviral Immunity and Immunopathology in the Lung: A Dissertation." eScholarship@UMMS, 2002. https://escholarship.umassmed.edu/gsbs_diss/188.

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Each individual experiences many sequential infections throughout the lifetime. An increasing body of work indicates that prior exposure to unrelated pathogens can greatly alter the disease course during a later infection. This can be a consequence of a phenomenon known as heterologous immunity. Most viruses invade the host through the mucosa of a variety of organs and tissues. Using the intranasal mucosal route of infection, the thesis focused on studying modulation of lymphocytic choriomeningitis virus (LCMV)-specific memory CD8 T cells upon respiratory vaccinia virus (VV) infection and the role of these memory CD8 T cells in heterologous immunity against VV and altered immunopathology in the lung. The VV infection had a profound impact on memory T cells specific for LCMV. The impact included the up-regulation of CD69 expression on LCMV-specific CD8 memory T cells and the activation of their in vivoIFN-γ production and cytotoxic function. Some of these antigen-specific memory T cells selectively expanded in number, resulting in modulation of the original LCMV-specific T cell repertoire. In addition, there was a selective organ-dependent redistribution of these LCMV-specific memory T cell populations in secondary lymphoid tissue (the mediastinal lymph node and spleen) and the non-lymphoid peripheral (the lung) organs. The presence of these LCMV-specific memory T cells correlated with IFN-γ-dependent enhanced VV clearance, decreased mortality and marked changes in lung immunopathology. Thus, the participation of pre-existing memory T cells specific for unrelated agents can alter the dynamics of mucosal immunity. This is associated with an altered disease course in response to a pathogen. The roles for T cell cross-reactivity and cytokines in the modulation of memory CD8 T cells during heterologous memory CD8 T cell-mediated immunity and immunopathology were investigated. Upon VV challenge, there were preferential expansions of several LCMV-specific memory CD8 T cell populations. This selectivity suggested that cross-reactive responses played a role in this expansion. Moreover, a VV peptide, partially homologous to LCMV NP 205, stimulated LCMV-NP205 specific CD8 T cells, suggesting that NP205 may be a cross-reactive epitope. Poly I:C treatment of LCMV-immune mice resulted in a transient increase but no repertoire alteration of LCMV-epitope-specific CD8 T cells. These T cells did not produce IFN-γ in vivo. These results imply that poly I:C, presumably through its induced cytokines, was assisting in initial recruitment of LCMV-specific memory CD8 T cells in a nonspecific manner. VV challenge of LCMV-immune IL-12KO mice resulted in activation and slightly decreased accumulation of LCMV-specific CD8 T cells. Moreover, there was a dramatic reduction of in vivoIFN-γ production by LCMV-specific IL-12KO CD8 T cells in the lung. I interpreted this to mean that IL-12 was important to augment IFN-γ production by memory CD8 T cells upon TCR engagement by antigens and to induce further accumulation of activated memory CD8 T cells during the heterologous viral infection. This thesis also systematically examined what effect the sequence of two heterologous virus challenges had on viral clearance, early cytokine profiles and immunopathology in the lung after infecting mice immune to one virus with another unrelated viruses. Four unrelated viruses, [LCMV, VV, influenza A virus or murine cytomegalovirus (MCMV)], were used. There were many common changes observed in the acute response to VV as a consequence of prior immunity to any of three viruses, LCMV, MCMV or influenza A virus. These included the enhanced clearance of VV in the lung, associated with enhanced TH1 type responses with increased IFN-γ and suppressed pro-inflammatory responses. However, immunity to the three different viruses resulted in unique pathologies in the VV-infected lungs, but with one common feature, the substitution of lymphocytic and chronic mononuclear infiltrates for the usual acute polymorphonuclear response seen in non-immune mice. Immunity to influenza A virus appeared to influence the outcome of subsequent acute infections with any of the three viruses, VV, LCMV and MCMV. Most notably, influenza A virus-immunity protected against VV but it actually enhanced LCMV and MCMV titers. This enhanced MCMV replication was associated with enhanced TH1 type response and pro-inflammatory cytokine responses. Immunity to influenza A virus appeared to dramatically enhance the mild lymphocytic and chronic mononuclear response usually observed during acute infection with either LCMV or MCMV in non-immune mice, but LCMV infection and MCM infection of influenza A virus-immune mice each had its own unique features. Thus, the specific sequence of virus infections controls the outcome of disease.

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Isorce, Nathalie. "Du criblage de l’activité antivirale de divers interférons et cytokines pro-inflammatoires contre HBV, vers la description du mécanisme antiviral de l’interleukine-1β dépendant de NF-κB". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10130.

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Dans les patients infectés par HBV, les thérapies avec les analogues de nucléos(t)ides (NAs) ou l'interféron α (IFNα) restent inefficaces pour éradiquer l'infection, à cause d'une forme persistante d'HBV, appelée l'ADN circulaire covalent clos (ADNccc), organisé comme un mini-chromosome. Notre but a été de revisiter l'activité anti-HBV d'un panel de cytokines in vitro en utilisant des hépatocytes non transformés, afin d'identifier de nouvelles options immunothérapeutiques. Parmi toutes les molécules testées, l'IFNβ, l'IFNγ, les IFNλ, le TNFα, l'IL-6, l'IL-1β et le ténofovir (ce dernier utilisé comme contrôle positif) ont montré un effet suppresseur sur la réplication d'HBV aussi fort et parfois plus fort que l'IFNα. La cytokine ayant l'effet le plus élevé sur l'ADN total d'HBV (EC50 ≈ 25 pg/mL), sans cytotoxicité, était l'interleukine-1β (IL-1β), qui est naturellement produite par les cellules de Kupffer (KC), les macrophages du foie. De façon importante, les ARNs totaux d'HBV et l'antigène sécrété HBeAg, mais pas HBsAg, ni l'ADNccc, sont fortement diminués par l'IL-1β. Nous avons donc émis l'hypothèse selon laquelle des promoteurs viraux spécifiques su l'ADNccc pourraient être inhibés, même si l'ADNccc n'est pas dégradé. Ensuite, nous avons étudié le mécanisme de l'activité antivirale de l'IL-1β. Nous avons montré que tous les promoteurs d'HBV sembleraient être inhibés par l'IL-1β. En parallèle, nous avons vérifié que l'IL-1β pouvait activer le promoteur de NF-κB, dont la fonction de transcription a été confirmée. Grâce à cette étude, l'IL-1β a été montré comme ayant un effet antiviral très efficace contre HBV in vitro, par l'intermédiaire de la fixation de NF-κB sur l'ADNccc In HBV-infected patients, therapies with nucleos(t)ide analogues (NAs) or interferon α (IFNα) remain ineffective in eradicating the infection, because of a persistent form of HBV DNA, namely the covalently closed circular DNA (cccDNA), which is organized as a minichromosome. Our aim was to revisit the anti-HBV activity of a panel of IFNs and pro-inflammatory cytokines in vitro using nontransformed cultured hepatocytes of HBV infection, to identify new immunotherapeutic options. Amongst all molecules tested, IFNβ, IFNγ, IFNλ, TNFα, IL-6, IL-1β and tenofovir showed a suppressive effect on HBV replication at least as strong as, but sometimes stronger than IFNα. The cytokine showing the highest effect on intracellular total HBV DNA without any cytotoxicity, was interleukin-1β (IL-1β), which is naturally produced by Kupffer cells (KC), representing the macrophages of the liver. Importantly, total HBV RNAs and secreted HBeAg, but nor HBsAg, neither cccDNA, were strongly decreased. Thus, we hypothesized that even if cccDNA was not degraded, specific viral promoters on cccDNA could be silenced. Then, we investigated the mechanism of IL-1β antiviral activity. We have shown that all HBV promoters were early inhibited by IL-1β. In the meantime, we have verified that IL-1β can induce nuclear Translocation and expression of NF-κB. We also checked NF-κB functionality. Thanks to this study, IL-1β has been found to have very potent antiviral effect against HBV in vitro, through the binding of NF-κB on cccDNA

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Barbaglia, Matteo. "Sex differences in hepatitis C virus infection: characterisation of 17,β-estradiol-modulated antiviral defences in an HCV cell culture system". Doctoral thesis, Università del Piemonte Orientale, 2021. http://hdl.handle.net/11579/127833.

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Chronic hepatitis C is one of the most widespread liver diseases in the world, with over 170 million individuals infected with the hepatitis C virus (HCV). Several clinical studies have observed a protective effect of female sex against HCV infection and HCV-related liver diseases. Our group have demonstrated that 17,β-estradiol (E2) is able to inhibit HCV life cycle in vitro but the antiviral mechanisms are still unknown. In the first part of the present study, we evaluated the E2-mediated activation of hepatocytes innate immunity. Several studies showed the relationship between hypoxia and E2 signaling pathway and the cellular hypoxic state appears to influence HCV infection and may play a significant role in viral hepatocarcinogenesis. In the second part of the study, we evaluated the relationship between HCV infection, hypoxia (induced by dimethyloxalylglycine (DMOG) treatment) and E2. We evaluated the persistence of the E2-mediated antiviral status after treatment removal and its impact on the infection susceptibility. The E2 antiviral activity loss resulted to be time-treatment dependent. Gene expression analysis of interferon-related genes was performed on E2-treated cells (w and w/o infection). We demonstrated that E2 up-regulate the innate immune gene transcription in naïve or infected cells. Also the conditioned medium (CM) produced by HuH7 cells post E2 treatment showed antiviral properties. Adding to E2 and CM treatment the an inhibitor of the IFN-α/IFNAR interaction, we obtained the complete antiviral effect loss; demonstrating that the E2-induced antiviral agents are linked to the interferon type I system. In the second part of the study, we found that the DMOG exerts opposite effects on viral infection, depending on exposure timing. Using the estrogen receptor (ER) agonist (E2) and antagonist (fulvestrant) compounds in combination with DMOG, we demonstrated a mutual interaction between the ER pathway and DMOG treatment effect on viral infection.

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El, Asmi Faten. "Rôle différentiel des isoformes de PML en réponse au trioxyde d’arsenic et dans la défense antivirale." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA11T102.

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Les interférons (IFN) constituent une famille de cytokines aux propriétés antiprolifératives et antivirales. Ils activent, via la voie Jak/STAT, des gènes spécifiques dont les produits sont les médiateurs des effets biologiques des IFN. C’est le cas de PML (Promyelocytic leukemia), appelée aussi TRIM19, qui joue un rôle central dans la défense antivirale. PML appartenant à la famille des protéines Tripartite Motif (TRIM), caractérisée par la présence en N-terminal d’un motif RBCC, constitué d’un domaine RING, d’une ou de deux boites B et d’un domaine coiled-coil. PML a été identifiée dans la leucémie aiguë promyélocytaire, une pathologie causée par la translocation chromosomique t(15 ;17) qui fusionne les gènes PML et RARA, aboutissant à la synthèse d'une protéine chimère PML-RARA. Le trioxyde d'arsenic (As2O3) cible la portion PML de la protéine oncogénique, entraînant sa dégradation et la rémission complète des patients. Dans les cellules saines, les transcrits PML issus d’un gène unique génèrent par épissage alternatif 7 isoformes principales de PML, dont six sont nucléaires (PMLI à PMLVI) et une cytoplasmique (PMLVIIb). Toutes possèdent la même extrémité N-terminale mais diffèrent au niveau de leur extrémité C-terminale, conférant à chaque isoforme des fonctions spécifiques.PML est l’organisatrice d’une structure multi-protéique appelée corps nucléaires (CN), impliquée dans divers processus cellulaires tels que l’apoptose, la dégradation des protéines ou encore la défense antivirale.PML est modifiée par SUMO de façon covalente au niveau de trois sites lysines (K65, K160, K490) et de façon non covalente, via son domaine SIM (pour « SUMO Interacting Motif »). Ces modifications sont requises pour la formation de CN fonctionnels et le recrutement de protéines partenaires au sein de ceux-ci. Le but de ma thèse a été d’étudier le rôle différentiel des différentes isoformes de PML en réponse à l’As2O3 et suite à l’infection virale. Nous avons montré que le SIM de PML est nécessaire à sa dégradation en réponse à l'As2O3. Ce motif est présent dans toutes les isoformes de PML, hormis l’isoforme nucléaire PMLVI et l’isoforme cytoplasmique PMLVIIb. Le SIM de PML n’est pas requis pour sa SUMOylation et son interaction avec RNF4 (une E3 ubiquitine ligase responsable de la dégradation de PML via le protéasome). En revanche, ce motif est requis pour l’ubiquitination de PML, le recrutement des composants du protéasome et sa dégradation en réponse à l’As2O3. Concernant les propriétés antivirales de PML, l’étude que nous avons menée avec toutes les isoformes de PML a permis de montrer que seules PMLIII et PMLIV confèrent une résistance au Virus de la Stomatite Vésiculaire (VSV). L’effet antiviral de PMLIII n'est observé qu'à faible multiplicité d’infection (MOI) et est indépendant de la production d’IFN. Par contre, PMLIV exerce une puissante activité anti-VSV, y compris à forte MOI et s'exerce selon deux mécanismes distincts : (i) PMLIV inhibe la réplication du VSV par un mécanisme précoce indépendant de l’IFN, (ii) PMLIV augmente tardivement la production d’IFN-β via une plus forte activation d’IRF3 qui est due à la séquestration spécifique de Pin1 au sein des CN par PMLIV. Ces deux processus nécessitent la SUMOylation de PMLIV. Ces résultats montrent que PMLIV exerce une activité antivirale intrinsèque et est impliquée dans l’immunité innée en régulant positivement la voie de transduction conduisant à la synthèse d’IFN-β Interferons (IFNs) are a family of cytokines with antiproliferative and antiviral properties.They activate, via the Jak/Stat pathway, specific genes whose products are the mediators of the biological effects of IFNs. This is the case of PML (Promyelocytic leukemia), also known as TRIM19, which plays a central role in antiviral defense.PML belongs to the Tripartite Motif (TRIM) protein family, characterized by the presence of an N- terminal RBCC pattern, consisting of a RING domain, one or two B-boxes and a coiled-coil domain. PML was identified in acute promyelocytic leukemia, a disease caused by the chromosomal translocation t(15 ;17), which fuses the PML and RARA genes, leading to the synthesis of a chimeric protein PML-RARA . Arsenic trioxide (As2O3) targets the PML moiety of the oncogenic protein, resulting in its degradation and in the complete remission of patients.In healthy cells, PML transcripts derived from a single gene generate seven major isoforms of PML by alternative splicing, including six nuclear (PMLI to PMLVI) and one cytoplasmic (PMLVIIb). All share the same N-terminus but differ at their C-terminus, giving each isoform specific functions.PML is the organizer of a multi-protein structure called nuclear bodies (NBs) that are involved in various cellular processes such as apoptosis, protein degradation or antiviral defense.PML is covalently modified by SUMO at three lysine residues (K65, K160, K490) but also non-covalently via its SIM domain (for « SUMO Interacting Motif »). These modifications are required for the formation of functional NBs and the recruitment of partner proteins within them.The aim of my thesis was to study the differential role of the different PML isoforms in response to As2O3 and during viral infection.We have shown that the SIM PML SIM is necessary for its degradation in response to As2O3. This motif is present in all PML isoforms, except the nuclear PMLVI and the cytoplasmic PMLVIIb isoforms. The SIM of PML is not required for its SUMOylation and its interaction with RNF4 (the E3 ubiquitin ligase responsible for PML proteasome-dependent degradation). However, this motif is required for the ubiquitination of PML, the recruitment of proteasome components and the degradation of PML in response to As2O3.Concerning the antiviral properties of PML, the study that we conducted with all PML isoforms allowed us to show that only PMLIII and PMLIV confer resistance to Vesicular Stomatitis Virus (VSV). Whereas the antiviral activity of PMLIII is only observed at low multiplicity of infection (MOI) and is independent of IFN production, PMLIV has a potent anti-VSV activity, including at high MOI, which is mediated through two distinct mechanisms: (i) PMLIV inhibits the replication of VSV by an early and IFN-independent mechanism, (ii) PMLIV later increases the production of IFN-β via a stronger activation of IRF3, which is due to the specific sequestration of Pin1 by PMLIV within NBs. Both processes require the PMLIV SUMOylation. These results show that PMLIV has an intrinsic antiviral activity and is also involved in innate immunity by positively regulating the transduction pathway leading to IFN-β synthesis

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Townsend, Hannah Leanne. "A phylogenetically conserved RNA structure within the poliovirus 3C ORF competitively inhibits the antiviral ribonuclease L /." Connect to full text via ProQuest. Limited to UCD Anschutz Medical Campus, 2008.

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Thesis (Ph.D. in Microbiology) -- University of Colorado Denver, 2008. Typescript. Includes bibliographical references (leaves 126-147). Free to UCD Anschutz Medical Campus. Online version available via ProQuest Digital Dissertations;

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Subramanian, Gayatri. "TDRD7, a Novel Viral Restriction Factor, Inhibits Cellular AMP-dependent Kinase to Inhibit Virus Replication." University of Toledo Health Science Campus / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=mco1596574176173965.

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羽者家, 宝. "植物内在性dsRNAによる全身性の免疫系活性化効果とその応用". Kyoto University, 2019. http://hdl.handle.net/2433/245330.

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Badillo, Herrera Jesus David Verfasser], Michael [Akademischer Betreuer] [Meyer-Hermann, and Martin [Akademischer Betreuer] Korte. "Mathematical Analysis of Receptor-Mediated Immune Cell Death in Innate Antiviral Immunity / Jesus David Badillo Herrera ; Michael Meyer-Hermann, Martin Korte." Braunschweig : Technische Universität Braunschweig, 2021. http://d-nb.info/1228071764/34.

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Lu, Hongjin. "Study of the interferon-oxysterol antiviral response and 3-Hydroxy-3-Methylglutaryl-CoA Reductase." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/25700.

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The oxysterol, 25-hydroxycholesterol (25-HC), is important for sterol metabolism and emerging evidence suggests that 25-HC plays a more critical role in immunity and infection. However, the precise antiviral mechanism and the target of 25- HC remains unclear. Here efforts were made to investigate the link between viral infection and the triggering of the 25-HC associated interferon (IFN) response, and how this dynamically alters the endogenous level of 3-hydroxy- 3-methylglutaryl-CoA reductase (HMGCR), a key enzyme that catalyses the production of the precursor of cholesterol and oxysterols. In this thesis I have sought to specifically explore the temporal changes and role of HMGCR in DNA virus (cytomegalovirus) and RNA (Influenza) virus infections. I hypothesise that HMGCR is a target for 25-HC associated IFN-mediated host defence against viral infection. To characterise HMGCR and test this hypothesis, the following objectives were defined: (1). To establish an experimental system to quantitatively study the endogenous HMGCR protein level; (2). To investigate the mechanism of the down-regulation of HMGCR involved in the IFN-mediated innate immune response; (3). To study the behaviour of HMGCR in the influenza virus induced 25-HC associated IFN-mediated innate immune response; (4). To study the behaviour of HMGCR in the cytomegalovirus induced 25-HC associated IFN-mediated innate immune response. Chapter 3, describes establishing an experimental system for the quantification of endogenous HMGCR levels. Different protein detection methods, including a modified western blot protocol and immunostaining, were tested. The results of RNA interference of HMGCR demonstrate that under lipid-deficient condition with the supplementation of mevastatin (an HMGCR inhibitor) the modified western blot protocol specifically detects endogenous HMGCR. This chapter lays the foundational work for the temporal analysis and testing the role of HMGCR in infection. In Chapter 4, the mechanism of the degradation of HMGCR following 25-HC and IFN treatments, in wild-type and Ch25h−/− mouse bone marrow derived macrophages (BMDMs), was investigated. Similar to 25-HC, IFN-γ treatment results in the drop of both the transcript and protein abundance of HMGCR in wild-type BMDMs. Differential temporal analysis of RNA and protein alterations and the use of proteasome inhibitors reveals that both 25-HC and IFN-γ lead to a marked reduction of HMGCR protein via a proteasomal degradation mechanism within early times of treatments. Further, the immediate reduction of HMGCR levels induced by IFN-γ was completely abrogated in Ch25h−/− BMDMs. Hence, the reduction of HMGCR following IFN-γ treatment is due to the de novo synthesis in macrophages of 25-HC. However, the decrease of Hmgcr gene expression was observed in not only wild-type but also Ch25h−/− BMDMs, suggesting additional mechanisms for regulating Hmgcr RNA levels. These results demonstrate the mechanism of the down-regulation of HMGCR resulted from the induction of IFN response during viral infection, is only partially due the de novo synthesis of 25-HC. In chapter 5, influenza A virus was used to investigate the role of HMGCR in the IFN-mediated innate immune response. The inhibition of HMGCR by RNA interference inhibited viral growth, suggesting the requirement of HMGCR for optimal intracellular viral growth. Viral infection in wild-type murine BMDMs reduced the endogenous HMGCR levels. However, the reduction of HMGCR at early times was prevented in Ch25h−/− BMDMs. Intriguingly, the decrease of HMGCR at late time points was still observed in Ch25h−/− BMDMs. These results indicate that the down-regulation of HMGCR with influenza virus infection in BMDMs at early times is completely due to the de novo synthesis of 25-HC; whereas at late times alternative pathways or mechanisms exist. Additionally, human epithelial A549 cells and A549/PIV5-V cells that are deficient in STAT1 were used to study the role of IFN pathway in the down-regulation of HMGCR at late times during viral infection. Results from these studies show that at late times the reduction of HMGCR is due to IFN-independent mechanisms. Chapter 6, extends these investigations to the herpes virus murine cytomegalovirus and infection of BMDMs. HMGCR is known to be essential for cytomegaloviral infections and 25-HC, statin and RNAi inhibition of HMGCR restrict viral growth. 25-HC is shown to reduce HMGCR at immediate early times of infection. However, most notably, the down-regulation of HMGCR was also observed in Ch25h−/− BMDMs at late times with murine cytomegalovirus infected BMDMs. These results confirm that alternative pathways or mechanisms exist, playing roles in the crosstalk between cholesterol metabolism and innate immune response. Collectively, this study characterises the role of HMGCR in the 25-HC associated IFN-mediated host defence against viral infection. Results indicate that, in addition to the IFN-mediated host response, alternative pathways or other mechanisms also result in the down-regulation of HMGCR during viral infection. HMGCR is at the crossroad of different pathways or mechanisms, and is therefore not only targeted by 25-HC. Hence, further questions can be addressed from these results: (1). What are the alternative pathways or mechanisms for the down-regulation of HMGCR? (2). How do these pathways or mechanisms work in hosts’ immune system? Answering these questions can contribute to refining the pathway map of innate immunity and understanding the precise role of HMGCR, or even the sterol biosynthesis pathway, in hosts’ immune response against pathogens.

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Morazzani, Elaine M. "Modulation of Alphaviruses by Small RNAs." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/39328.

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Mosquito-borne diseases remain a significant burden on global public health. Maintenance of mosquito-borne viruses in nature requires a biological transmission cycle that involves alternating virus replication in a susceptible vertebrate and mosquito host. Although infection of the vertebrate host is acute and often associated with disease, continual transmission of these viruses in nature depends on the establishment of a persistent, nonpathogenic infection in the mosquito vector. It is well known that invertebrates rely on small RNA pathways as an adaptive antiviral defense. The canonical antiviral response in these organisms involves dicer enzymes that cleave viral double-stranded RNA replicative intermediates (RIs) into small interfering RNAs (siRNAs; ~21-24 nucleotides). One strand of the siRNA duplex guides the targeting and destruction of complementary viral RNAs when loaded and retained in a multi-protein complex called the RNA-induced silencing complex. Here, we show that mosquito vectors mount a redundant double defense against virus infection mediated by two different small RNA pathways. Specifically, we demonstrate that in addition to a canonical antiviral response mediated by siRNAs, virus infection of the mosquito soma also triggers an antiviral immune pathway directed by ping-pong-dependent PIWI-interacting RNAs (piRNAs; ~24-30 nucleotides). The complexity of mosquito antiviral immunity has important implications for understanding how viruses both induce and modulate RNA-silencing responses in mosquito vectors. In mammals, viral RIs induce a range of relatively nonspecific antiviral responses. However, it remains unclear if viral RIs also trigger RNA silencing in mammals. Mosquito-borne viruses represent an ideal model for addressing this question as their transmission cycles involve alternating replication in mammalian and invertebrate hosts. Although we report identifying a subset of virus-derived small RNAs that appear to be products of RNA silencing in two mammalian cell lines infected with the mosquito-borne chikungunya virus (CHIKV), our studies suggest these small RNAs have little biological relevance in combating virus infections. Thus, while the accumulation of virus-derived siRNAs is essential to the survival of mosquitoes infected with CHIKV, they appear to have little functional significance in mammalian antiviral immunity. Ph. D.

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Bezerra, Thiago de Almeida. "Avaliação da imunidade antiviral no lavado nasal de pacientes com imunodeficiência comum variável em vigência de rinossinusites virais." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5133/tde-10032017-085135/.

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INTRODUÇÃO: Imunodeficiências primárias são um grupo heterogêneo de distúrbios de origem genética que afetam a imunidade e se caracterizam por infecções de repetição. Aproximadamente metade dos casos estão ligados a deficiências humorais e dentre estas podemos destacar a Imunodeficiência Comum Variável (ICV). Uma vez que os pacientes com ICV possuem redução dos níveis de anticorpos, esses pacientes apresentam infecções recidivantes do trato respiratório e aproximadamente 90% tiveram no mínimo um episódio de rinossinusite (RNS). A RNS se instala devido ao desequilíbrio entre o meio ambiente e fatores do hospedeiro e a infecção viral é pelo menos 20 vezes mais frequente do que a infecção bacteriana em indivíduos normais. OBJETIVOS: (1) Identificar os agentes virais da RNS nos pacientes com ICV e em indivíduos controles em um contexto prospectivo; (2) Definir quais citocinas e quimiocinas estão presentes e avaliar a expressão de genes relacionados à imunidade inata e adaptativa antiviral no lavado nasal de pacientes com ICV e nos indivíduos controles. CASUÍSTICA, MATERIAIS E MÉTODOS: Pacientes com ICV e indivíduos controles foram avaliados quando apresentavam sinais e sintomas de uma RNS viral e foi realizado a coleta de lavado nasal para a identificação de vírus respiratórios, além da quantificação da secreção de citocinas e quimiocinas e da avaliação da expressão gênica de genes relacionados à imunidade inata e adaptativa antiviral. A avaliação foi repetida quando todos os indivíduos previamente estudados se encontravam assintomáticos. RESULTADOS: De abril de 2012 a novembro de 2014, foram colhidas 65 amostras de lavado nasal, 43 amostras de 34 indivíduos controles e 22 amostras de 14 pacientes com ICV. Quatro amostras foram positivas para vírus pela técnica da imunofluorescência direta e dezoito amostras foram positivas pelo PCR. Pacientes com ICV tiveram mais infecções, duração maior dos sintomas e maior necessidade de uso de antibióticos que o grupo controle. A avaliação da produção de citocinas e quimiocinas no lavado nasal mostrou aumento da secreção de CXCL10, CCL2, CCL5, CXCL8 IL-6, IL-10, IL-1beta e TNF em ambos os grupos quando esses apresentavam quadro agudo de RNS viral. Foi realizada a expressão de genes pela técnica do PCR Real Time. Os pacientes com ICV apresentaram um aumento de expressão de genes relacionados à imunidade inata e adaptativa anitiviral substancialmente maior frente a um quadro de RNS viral do que os indivíduos controles em situações semelhantes. Quando comparamos os pacientes ICV e os controles ambos sem infecção aguda, observamos que os genes apresentam em sua maioria uma redução de expressão nos pacientes com ICV. DISCUSSÃO: Os vírus detectados respeitaram a sazonalidade em que normalmente são detectados e pacientes com ICV proporcionalmente tiveram mais infecções e uma evolução pior que o grupo controle. Aparentemente não houve diferenças significativas entre os grupos estudados quanto à liberação de citocinas e quimiocinas. Com relação ao estudo da expressão gênica, a maior amplitude de variação observada nos pacientes com ICV pode significar um desajuste de resposta imune levando a um quadro de maior inflamação local com consequente maior dano tecidual e justificando assim a incidência aumentada de complicações, duração aumentada dos sintomas e replicação viral aumentada nesse grupo de pacientes INTRODUCTION: Primary immunodeficiencies (PIDs) are a heterogeneous group of genetic disorders that affect immunity and are characterized by relapsing, usually severe infections. Approximately half of the cases are linked to humoral deficiencies, being common variable immunodeficiency (CVID) the most frequent. CVID patients have reduced levels of antibodies; therefore, these patients have recurrent infections in the respiratory tract and approximately 90% had at least one episode of rhinosinusitis (RS). RS installs itself due to the imbalance between the environment and host factors and viral infection is at least 20 times as common as the bacterial infection in normal individuals. OBJECTIVES: (1) Identify the viral agents of rhinosinusitis in patients with CVID and in control individuals on a prospective context; (2) define which cytokines and chemokines are present in the nasal wash and evaluate the expression of genes related to innate and adaptive antiviral immunity in nasal wash of CVID patients and in control individuals. CASES, MATERIALS, AND METHODS: patients with CVID and control individuals were examined at Outpatient Facility of Dermatological Manifestations of Primary Immunodeficiencies and when they presented signs and symptoms of a viral RS. Nasal wash was collected in order to identify respiratory viruses; secretion of cytokines and chemokines were quantified and gene expression of genes related to innate and adaptive antiviral immunity were evaluated. This evaluation was repeated when all individuals previously studied were asymptomatic. RESULTS: From April 2012 to November 2014, 65 samples of nasal wash, 43 samples of 34 control individuals and 22 samples of 14 patients with CVID were collected. Four samples were positive for virus by direct immunofluorescence technique and eighteen samples by PCR. The detected viruses behaved according to the season in which they are normally detected and patients with CVID proportionally had more and longer infections and required more antibiotics than the control group. The evaluation of the production of cytokines and chemokines showed an increased secretion of CXCL10, CXCL8 CCL2, CCL5, IL-6, IL-10, IL-1beta and TNF in both groups when they presented acute viral RS. Gene expression was performed by using Real Time PCR. CVID patients showed increased expression of genes related to innate and adaptive antiviral immunity when compared to control individuals presenting acute viral RS. Conversely, when we compared CVID patients and control individuals both without acute infection, we observed a reduction in gene expression in CVID patients. DISCUSSION: The viral rhinosinusitis respected seasonality and CVID patients had proportionally more infections and a worse evolution than the control group. Apparently, there were no significant differences between the groups regarding the release of cytokines and chemokines. The greater magnitude of gene expression variation observed in CVID patients suggests an imbalance of immune response leading to a state of greater local inflammation with consequent greater tissue damage, therefore justifying an increased incidence of complications, increased duration of symptoms and increased viral replication in this group of patients

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Oladunni, Fatai S. "MECHANISMS OF TYPE-I IFN INHIBITION: EQUINE HERPESVIRUS-1 ESCAPE FROM THE ANTIVIRAL EFFECT OF TYPE-1 INTERFERON RESPONSE IN HOST CELL." UKnowledge, 2019. https://uknowledge.uky.edu/gluck_etds/43.

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Equine herpesvirus-1 (EHV-1) is one of the most important and prevalent viral pathogens of horses causing a major threat to the equine industry throughout most of the world. EHV-1 primarily causes respiratory disease but viral spread to distant organs enables the development of more severe sequelae; abortion and neurologic disease. In order to produce disease, EHV-1 has to overcome the innate barrier of the type-I interferon (IFN) system in host cells. However, the underlying mechanisms employed by EHV-1 to circumvent the type-I IFN response in host cells are not well understood. In this project study, using molecular techniques, we explored how EHV-1 is able to escape the type-I IFN response in host cells during infection. We also investigated whether EHV-4, a closely related but less pathogenic virus, has similar effects on type-I IFN as a clue to understanding how widespread IFN suppressive function is found among equine alphaherpesviruses. Our data showed that inhibition of the type-I IFN response in host cells is not a function of neuropathogenicity of EHV-1 strains. However, a reduced type-I IFN response correlated with pathogenicity as EHV-4, unlike EHV-1, was unable to down-regulate the type-I IFN response in equine endothelial cells (EECs). Investigation of the mechanisms employed by EHV-1 to suppress type-I IFN revealed that the virus sequentially prevented outside-in signaling events that lead to type-I IFN production. Specifically, EHV-1 blocked the expression of Toll-like receptors (TLR) 3 and TLR4 at 6 hours post-infection (hpi) and 12 hpi. EHV-1 also prevented the transcription of IRF7 and IRF9 at different time-points during infection. The virus also perturbed the JAK-STAT signaling pathway by negatively regulating the cellular levels of TYK2 and phosphorylation-mediated activation of STAT2 molecules. Immunofluorescence data revealed that during infection, EHV-1 was able to sequester STAT2 molecules from nuclear translocation. This may be a limiting step preventing the formation of interferon- stimulated gene factor 3 (ISGF3) whose nuclear translocation is required to transactivate interferon-stimulated genes (ISGs) including IRF7. Further investigation showed that unlike EHV-1, EHV-4 only interfered with phosphorylation-mediated activated STAT1 and STAT2 molecules at 3 and 6 hpi. EHV-4 was unable to block TLR3/4 and IRF7/9 mRNA expression at any time-point. Intriguingly, while viral late gene of EHV-1 mediates inhibition of STAT phosphorylation, our data showed that for EHV-4, a virus late gene did not mediate the inhibition of STAT phosphorylation. The findings from this study help illuminate how EHV-1 strategically interferes with limiting steps required for type-I IFN response in host cells to promote pathology. Our data also strengthen the hypothesis that the ability to shut off host factors required for type-I IFN production might be directly related to the degree of pathogenicity of the EHV subtypes.

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Pourcelot, Marie. "Implication de l’appareil de Golgi et de l’ubiquitination dans l’activation de TBK1 après détection des ARNs viraux." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS230/document.

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L’immunité innée antivirale repose en grande partie sur la production des interférons de type I (IFN-α/β) par les cellules infectées et les cellules immunitaires. Cette synthèse résulte de la reconnaissance de motifs viraux caractéristiques par des récepteurs cellulaires, parmi lesquels les RIG-I-Like Récepteurs (RLR) et le Toll-Like Récepteur 3 (TLR3) détectent l’ARN viral respectivement au niveau du cytosol et des endosomes. La signalisation induite par les RLRs et TLR3 conduit à l’activation d’IRF3 et de NF-κB, deux facteurs de transcription impliqués respectivement dans la production d’IFN-α/β et de cytokines pro-inflammatoires. TBK1 (TANK-Binding Kinase 1) joue un rôle essentiel dans l’immunité innée antivirale, de par la phosphorylation du facteur de transcription IRF3, nécessaire à la production des IFNs de type I. Bien que de nombreuses études aient montré le rôle crucial de cette kinase dans la signalisation antivirale, le processus entrainant son activation est encore mal déterminé à ce jour. Lors de cette étude nous avons démontré que suite à la stimulation du TLR3 et des RLRs, la forme active, ubiquitinylée et phosphorylée, de TBK1 se relocalise au niveau de l’appareil de golgi, grâce à son ubiquitination sur les résidus K30 et K401. Ce mécanisme implique la reconnaissance des chaines d’ubiquitines associées à TBK1 par l’Optineurine (OPTN), permettant la formation d’un complexe autorisant le rapprochement des molécules de TBK1 puis la trans-autophosphorylation au niveau de l’appareil de Golgi. Au cours de ce travail nous avons également découvert qu’OPTN est la cible d’une protéine virale, la protéine NS3 du BTV (Bluetongue Virus), qui neutralise son activité et diminue ainsi l’activation de TBK1 et la signalisation responsable de la sécrétion de cytokines antivirales Type-I interferons (IFN-α/β) production and release is a major event in innate antiviral immunity. IFN production depends on the interaction between viral structures and their corresponding cellular sensors. RIG-I-Like Receptors (RLRs) and Toll-Like Receptor 3 (TLR3) sense dsRNAs in the cytosol and endosomes respectively. Stimulation of these receptors by their ligands promotes a signal transduction leading to the activation of the transcription factors NF-κB and IRF3, and consequently to the production of proinflammatory cytokines and Type I Interferons (IFN-I). TBK1 (TANK-Binding Kinase 1), plays a crucial role in antiviral innate immunity, by phosphorylating the transcription factor IRF3, required for the production of type I IFNs. Although many studies have shown the critical role of this kinase in antiviral signaling, the molecular mechanism of its activation are largely unknown. We report here the localization of the ubiquitinated and phosphorylated active form of TBK1 to the Golgi apparatus after the stimulation of RLRs or TLR3, due to TBK1 ubiquitination on lysine residues 30 and 401. The ubiquitin-binding protein optineurin (OPTN) recruits ubiquitinated TBK1 to the Golgi apparatus, leading to the formation of complexes in which TBK1 is activated by trans-autophosphorylation. We also found that a viral protein binds OPTN at the Golgi apparatus, neutralizing its activity and thereby decreasing TBK1 activation and downstream signaling

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Barbier, Vincent. "Pastrel, a restriction factor for picornalike-viruses in Drosophila melanogaster." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAJ114/document.

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La drosophile est un excellent modèle pour l’étude des mécanismes moléculaires de l’immunité innée, y compris les virus. Elle a permis la caractérisation de mécanismes de défense immunitaire conservés au cours de l’évolution, tel que les voies Toll et IMD qui régulent l’expression des peptides antimicrobiens induits en réponse aux infections fongiques et bactériennes. Deux types de réponse sont impliqués dans le contrôle des infections virales chez la drosophile : une réponse inductible et l’ARN interférence. Nous avons montré que l’ARN interférence est un mécanisme global de défense antivirale puisqu’il contrôle l’infection par un virus à ADN, en plus des virus à ARN tel que le virus C de la drosophile (DCV). Le virus DCV, apparenté aux Picornaviridae, est un pathogène naturel de la drosophile. Nous avons également observé que la résistance de mouches contrôles à l’infection par le virus DCV est dépendante du fond génétique. Elle est d’ailleurs corrélée à des polymorphismes présents dans un gène porté par le chromosome III : le gène pastrel. Nos expériences de perte et gain de fonction indiquent que ce gène code pour un facteur de restriction viral, bloquant l’infection par le virus DCV mais aussi par le virus de la paralysie du cricket (CrPV). Cette restriction apparait dans les premières heures après infection. La région C-terminale de la protéine Pastrel est nécessaire à son activité antivirale ainsi qu’à sa localisation dans les cellules. La protéine Pastrel co-localise avec le Rouge de Nil, un marqueur des gouttelettes lipidiques. Ainsi, nos résultats suggèrent un lien entre le métabolisme lipidique et le blocage d’une infection virale chez la drosophile Since the discovery of the evolutionarily conserved TOLL and IMD pathways, involved in antifungal and antibacterial immune responses, the fruit fly Drosophila melanogaster is used as a model to study the molecular mechanisms of innate immunity. To defend against viral pathogens, Drosophila relies on two main facets: the RNA interference (RNAi) pathway and virus specific inducible responses. We show that the RNAi pathway plays a role in the control of a DNA virus, in addition to RNA viruses. We also observe that the fly genetic background can modulate the resistance to infection by Drosophila C virus (DCV), a natural pathogen of Drosophila. This resistance to DCV infection is correlated with polymorphisms in a gene named pastrel,localized on the left arm of the third chromosome. Our loss- and gain-of-function experiments indicate that pastrel encodes a molecule opposing infection by picorna-like viruses DCV and also Cricket Paralysis virus (CrPV), raising the question of the mechanism involved. This restriction appears early after infection. The Cterminal region of Pastrel protein is important for its antiviral activity and its localization in vesicular structures co-localizing with Nile Red staining, a marker for lipid droplets. Altogether, our data suggest a connection between lipid droplets and restriction of viral infection in Drosophila, as already described in mammals between the restriction factor Viperin, present on lipid droplets, and the replication of the human pathogen Hepatitis C Virus

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Le, Van Tuan [Verfasser], Uwe Gerd [Akademischer Betreuer] Liebert, and Uwe Gerd [Gutachter] Liebert. "Establishment of a memory B cell assay using recombinant Flavivirus protein for determinant of specific antiviral immunity / Tuan Le Van ; Gutachter: Uwe Gerd Liebert ; Betreuer: Uwe Gerd Liebert." Leipzig : Universitätsbibliothek Leipzig, 2014. http://d-nb.info/1238789307/34.

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