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Measles virus (MV) causes an acute childhood disease, associated in certain cases with the infection of the central nervous system (CNS). MV induces a profound immunosuppression, resulting in high infant mortality. The major cellular receptor for MV is CD150, which binds MV hemagglutinin (MV-H). As dendritic cell (DC) dysfunction is considered to be essential for the MV immunopathogenesis, we analyzed consequences of MV-H interaction with DCs. We developed an experimental model allowing us to analyze the direct CD150-MV-H interaction in the absence of infectious context. This interaction caused the downregulation of surface expression of CD80, CD83, CD86 and HLA-DR molecules and inhibition of IL-12 production in DCs. DCs also failed to activate T cell proliferation. The CD150-MV-H interaction in DCs and B cells decreased the phosphorylation of JNK1/2, but not ERK1/2 kinases, after subsequent CD150 ligation with anti-CD150 antibodies. Moreover, MV-H by itself induced Akt phosphorylation via CD150 in DCs and B cells. Engagement of CD150 by MV-H in mice transgenic for human CD150 decreased the inflammatory reaction, contact hypersensitivity response, confirming the immunosuppressive effect of CD150-MV-H interaction in vivo. Furthermore, our studies revealed the CD150 expression in CNS tumors and identified the novel CD150 isoform, containing an additional 83bp exon expressed in lymphoid cells, DCs and CNS tumors. Although its isoforms remain intracellular in tumor cells, CD150 may represent a new marker for human brain tumors. Novel mechanism of CD150-induced immunosuppression and new CD150 isoform identified in these studies shed new light on its immunoregulatory role and CD150 isoform diversity and open perspectives for their clinical applications.

Cette thèse porte sur la modélisation des comportements individuels de vaccination. Lorsque la vaccination est libre, les individus peuvent décider ou non de se vacciner, et ces décisions influencent la propagation de la maladie. Nous proposons une approche de modélisation flexible qui permet de prendre en compte ces décisions individuelles dans les modèles de simulation épidémiologiques.Dans le Chapitre 1, nous étudions la décision de vaccination face à une maladie inspirée de la rougeole. Nous montrons comment inclure les décisions de vaccination dans un modèle épidémiologique en les calculant comme un point fixe fonctionnel. Nous obtenons des résultats pour un modèle avec taux de mort et de naissance, et perte d'immunité vaccinale. Nos résultats sur longue période de temps mettent en évidence des pics épidémiques récurrents. À titre de comparaison, nous produisons également des résultats pour des individus ayant un comportement adaptatif.Les objectifs du Chapitre~2 sont (i) de montrer que la boucle entre prévalence et comportements individuels ne peut pas être négligée dans les évaluations de politiques de santé publique, et (ii) de présenter un outil pour les inclure dans ces évaluations. Nous développons l'exemple de la vaccination obligatoire contre la rougeole. Notre modèle épidémiologique est le modèle SIR habituellement utilisé pour représenter la rougeole. Nos résultats suggèrent que l'anticipation de la vaccination obligatoire peut conduire à une augmentation transitoire de la prévalence avant l'éradication à long terme de la maladie. Ceci conduirait à d'importants transferts d'utilité entre générations. Ironiquement, dans notre scénario, des individus anti-vaccins sont parmi ceux qui bénéficient le plus de la vaccination obligatoire.Dans le Chapitre~3, nous partons du constat que la comparaison des coûts de vaccination avec le risque d'être infecté par la rougeole peine à expliquer la couverture vaccinale relativement élevée (bien que souvent insuffisante) dans les pays développés. Nous discutons l'hypothèse selon laquelle la vaccination est un comportement coopératif. Nous mettons en œuvre des concepts d'équilibre et de punition habituellement utilisés en théorie des jeux répétés en donnant des arguments pour leur utilisation dans le contexte de la vaccination. Nos résultats indiquent que la menace d'une punition peut expliquer la vaccination lorsqu'elle serait normalement sous-optimale. / We tackle the issue of including individual vaccination decisions in epidemiological models. We draw on the example of Measles vaccination, and we focus on strategic interactions and anticipatory behavior. We contribute to a fuller account of such behaviors by developing a modeling approach intended as a tool for practitioners and theorists.In Chapter 1, we show how the interplay between individual anticipatory vaccination decisions and the otherwise biological dynamics of a disease may lead to the emergence of recurrent patterns. We consider a Measles-like outbreak, rational and far-sighted individuals, vital dynamics, and waning vaccine efficacy. This chapter illustrates the versatility of our approach. For comparison, we provide results for individuals with adaptive behavior.In Chapter 2, we investigate the effect of anticipatory behavior in a scenario where Measles vaccination becomes mandatory. When mandatory vaccination is announced in advance, we show that individuals may alter their vaccination behavior, thus causing an increase in prevalence before Measles is ultimately eradicated. These transition effects lead to non negligible welfare differences between generations. We consider an anti-vaccinationist subpopulation with a higher vaccination cost, and exhibit scenarios where anti-vaccinationists are among those who benefit the most from mandatory vaccination.In Chapter 3, we discuss whether coalitions of vaccinating individuals can account for the relatively high vaccination coverages observed in developed countries. We explain why and how retaliation concepts usually found in repeated games can be used in the context of vaccination, even though individuals vaccinate only once. This allows us to model how vaccinating individuals might retaliate against those who refuse vaccination. We show that retaliation threats can sustain vaccination where it would otherwise be suboptimal for individuals.

Environ 40 pour cent du protéome humain est composé d'importantes régions dépliées. Ces protéines intrinsèquement désordonnées (PID) n'adoptent pas de structures secondaires et tertiaires stables mais échantillonnent un vaste paysage conformationnel. Malgré cela, elles sont aujourd'hui connues pour intervenir dans de nombreux processus biologiques ou pathologiques. À l'instar des eucaryotes, les virus -- surtout les virus à ARN -- ont eux aussi recours aux propriétés particulières des PID pour effectuer les interactions nécessaires à leur réplication. Les paramyxovirus, comme le virus de la rougeole, sont des virus à ARN simple brin de polarité négative et environ 10 pour cent de leur génome de 15 à 18 kilobases code pour des régions dépliées. Cette thèse détaille l'étude de deux protéines virales directement impliquées dans la réplication, la nucléoprotéine et la phosphoprotéine. Elles interagissent l'une avec l'autre et sont composées à la fois de régions dépliées et repliées. Des données à résolution atomique ont été obtenues en spectroscopie par Résonance Magnétique Nucléaire (RMN) en ce qui concerne les parties désordonnées, et en cristallographie pour ce qui est des parties repliées. Les résultats apportent un nouvel aperçu du rôle du désordre conformationnel dans la transcription et la réplication des paramyxovirus. / About 40 percent of the human proteome contains large disordered regions. These intrinsically disordered proteins (IDPs) do not adopt stable secondary and tertiary structures, but sample a large conformational space. In spite of that, they are now known to be involved in many physiological as well as pathological processes. Following the example of eukaryotes, viruses -- especially RNA viruses -- benefit from the particular features of IDPs in their replication machinery. Paramyxoviruses, that includes Measles virus, are single stranded, negative sense RNA viruses and about 10 percent of their 15 to 18 kilobase RNA genome is known to encode for disordered regions. This thesis focuses on the study of two different proteins of paramyxoviruses, namely the nucleoprotein and the phosphoprotein that are directly involved in the replication of the viral genome. They interact with each other and are composed of folded and disordered domains. Atomic resolution information is obtained about the structure and dynamics of these proteins using a combination of Nuclear Magnetic Resonance (NMR) spectroscopy measurements for the disordered parts and X-ray crystallography for the folded domains. The results provide novel insight into the role of conformational disorder in transcription and replication of paramyxoviruses.

In regions where endemic measles virus circulation has been interrupted, laboratory confirmation of measles is like puzzle solving. The complexity of these puzzles depends on the available pieces of clinical, epidemiological and laboratory information. The main goal of this dissertation is to evaluate diagnostic laboratory tools to aid in suspected case confirmation in these settings. First, protocols to elute measles IgM and IgG antibodies from blood spots dried onto filter paper were compared to propose one that will permit the recovery of the maximum volume of eluted sample in the minimum time, effort and cost. An easy-to-implement protocol is proposed for the rapid extraction of serum for measles/rubella serology in outbreak situations for use in the World Health Organization Global Measles and Rubella Laboratory Network. Second, due to inherent limitations of measles specific IgM enzyme immunoassays and molecular methods used for measles confirmation, not all suspected cases can be resolved. For example, IgM and RNA may not be detected in vaccinated cases with waning immunity (secondary vaccine failures) and presenting with modified measles. The observation is made that serological parameters of elevated titers of high avidity neutralizing antibodies correlate with measles secondary vaccines failures and may be useful biomarkers for confirming secondary vaccine failures that cannot be confirmed otherwise. Third, a highly accurate measles IgG avidity enzyme immunoassay for vaccine failure classification is described. Detection of low avidity antibodies using this highly sensitive and specific avidity assay can complement existing measles diagnostic tools in confirming suspected cases when routine IgM testing may be inconclusive. Therefore, these diagnostic approaches can provide additional laboratory information to resolve suspected cases irrespective of vaccination status. Together, data presented in this dissertation may assist in enhancing measles control and surveillance in elimination settings. / En les regions on s'ha interromput la circulació del virus del xarampió endèmic, la confirmació del xarampió a nivell de laboratori és com resoldre trencaclosques. La complexitat d'aquests trencaclosques depèn de les peces disponibles d'informació clínica, epidemiològica i de laboratori. L'objectiu principal d'aquesta tesi doctoral és avaluar eines de diagnòstic de laboratori per a ajudar en la confirmació de casos sospitosos en regions on el xarampió està eliminat. En primer lloc, es van comparar protocols per a eluir les IgM i IgG anti-xarampionoses de mostres de taques de sang seca sobre paper de filtre i proposar un protocol que permetés la recuperació del volum màxim de mostra eluïda en el mínim temps, esforç i cost. Es proposa un protocol de fàcil implementació dins de la xarxa de laboratoris de rubèola i xarampió de l'Organització Mundial de la Salut per a ser usat en situacions de brot. En segon lloc, les IgM anti-xarampionoses i l’ARN del virus del xarampió poden no ser detectats en casos vacunats amb disminució de la immunitat (fallada vacunal secundària) i amb simptomatologia de xarampió modificada. L'observació de que paràmetres serològics de títols elevats d'anticossos anti-xarampionosos neutralizants i d'alta avidesa correlacionen amb fallades vacunals secundàries permet proposar aquests paràmetres com a biomarcadors útils per a confirmar aquestes fallades vacunals quan d'altra manera no podrien confirmar-se. En tercer lloc, es descriu un assaig immumoenzimàtic per a determinar l'avidesa de les IgG contra el virus del xarampió per a la classificació de fallades vacunals. Aquest assaig és altament sensible, específic i precís. La detecció d'anticossos de baixa avidesa mitjançant aquest assaig pot a més complementar les eines actuals de diagnòstic de xarampió en la confirmació de casos sospitosos quan les proves rutinàries de IgM no són concloents. Per tant, aquestes estratègies diagnòstiques poden proporcionar informació de laboratori addicionals per a resoldre casos sospitosos de xarampió independentment del seu estat de vacunació. Les dades presentades en aquesta tesi doctoral poden ajudar a millorar el control del xarampió i vigilància epidemiològica allà on el xarampió ja està eliminat.

Mass gatherings stress local and global health care systems as they bring together individuals from all over the world that have very different health conditions. We firstly provide an overview of the concepts and results of mathematical epidemiology and public health. Secondly, we present an introduction to the mathematical modelling of measles using deterministic and stochastic approaches for both single and multiple populations. Lastly, we develop a model for mass gatherings and present an application to measles during the Hajj by studying an SIR deterministic metapopulation model with residency and its stochastic analogue. The models incorporate real world country data and time dependent movement and transmission rates, accounting for realistic volume of international travel and seasonality of measles activity. Numerical results for the deterministic system are presented. We conclude with a discussion on further work.

Mass gatherings stress local and global health care systems as they bring together individuals from all over the world that have very different health conditions. We firstly provide an overview of the concepts and results of mathematical epidemiology and public health. Secondly, we present an introduction to the mathematical modelling of measles using deterministic and stochastic approaches for both single and multiple populations. Lastly, we develop a model for mass gatherings and present an application to measles during the Hajj by studying an SIR deterministic metapopulation model with residency and its stochastic analogue. The models incorporate real world country data and time dependent movement and transmission rates, accounting for realistic volume of international travel and seasonality of measles activity. Numerical results for the deterministic system are presented. We conclude with a discussion on further work.

Measles is one of the most contagious diseases known to mankind. Despite the availability of a safe and effective vaccine, approximately 164,000 measles-related deaths were recorded in 2008. The inherent restricted host tropism of MV means that the development of authentic rodent models will be a valuable research tool in testing new vaccines and antivirals. In addition to the receptor requirement, mouse innate immunity has been shown to inhibit MV growth. In this thesis, the contributions of several key components of the mouse innate immune system on the inhibition of MV replication were examined. The transcription factor interferon regulatory factor 3 (IRF3), which normally plays a key role in mediating innate immune signaling, contributed relatively little in inhibiting MV replication both in vitro and in vivo. In contrast, the JAK/STAT pathway and the double-stranded RNA inducible protein kinase, PKR, played more important roles in controlling virus replication. The resurgence of measles in areas where the virus was once thought to be eradicated makes the development of anti-MV treatments essential. Concurrent to the development of an animal model to better study its pathogenesis, we wanted to look at the effect of MV inhibitors on its replication. The MV fusion inhibitor, carbobenzoxy-D-phenylalanine-L-phenylalanine-glycine (ZfFG), was developed in the past to study fusion; however, its mechanism of action has not yet been elucidated. To examine this, spontaneous ZfFG-resistant mutants were generated and characterized. Mutations were found in the HRB region of the fusion (F) protein, and when these were modeled using published paramyxovirus F crystal structures, data suggested that ZfFG targeted a small pocket present between the head and stalk regions of its pre-fusion conformation. An authentic mouse model of measles developed from findings in this study may allow for in vivo efficacy testing of ZfFG in the future.

Measles is one of the most contagious diseases known to mankind. Despite the availability of a safe and effective vaccine, approximately 164,000 measles-related deaths were recorded in 2008. The inherent restricted host tropism of MV means that the development of authentic rodent models will be a valuable research tool in testing new vaccines and antivirals. In addition to the receptor requirement, mouse innate immunity has been shown to inhibit MV growth. In this thesis, the contributions of several key components of the mouse innate immune system on the inhibition of MV replication were examined. The transcription factor interferon regulatory factor 3 (IRF3), which normally plays a key role in mediating innate immune signaling, contributed relatively little in inhibiting MV replication both in vitro and in vivo. In contrast, the JAK/STAT pathway and the double-stranded RNA inducible protein kinase, PKR, played more important roles in controlling virus replication. The resurgence of measles in areas where the virus was once thought to be eradicated makes the development of anti-MV treatments essential. Concurrent to the development of an animal model to better study its pathogenesis, we wanted to look at the effect of MV inhibitors on its replication. The MV fusion inhibitor, carbobenzoxy-D-phenylalanine-L-phenylalanine-glycine (ZfFG), was developed in the past to study fusion; however, its mechanism of action has not yet been elucidated. To examine this, spontaneous ZfFG-resistant mutants were generated and characterized. Mutations were found in the HRB region of the fusion (F) protein, and when these were modeled using published paramyxovirus F crystal structures, data suggested that ZfFG targeted a small pocket present between the head and stalk regions of its pre-fusion conformation. An authentic mouse model of measles developed from findings in this study may allow for in vivo efficacy testing of ZfFG in the future.

Uppsatsens syfte har varit att ur ett socialkonstruktivistiskt perspektiv, undersöka hur olika grupper framställs journalistiskt i nyhetsrapporteringen av mässlingsutbrottet i Göteborg under vintern 2017-2018. Undersökningen har genomförts med kritisk diskursanalys och resultaten har analyserats med postkolonial teori samt teorier om nyheter som kulturell gemenskap och nyhetslogik. I material framkom två huvudsakliga diskurser; folkhälsodiskursen och antivaccinationsdiskursen. Vid sidan av dem framkom en latent främlingsfientlig diskurs. Undersökningen visar att medial konstruktion av ”den andre” sker gällande två grupper i materialet; vaccinationsmotståndare och migranter. Det undersökta materialet är inte direkt främlingsfientligt men indikerar tydligt en främlingsfientlig diskurs. Undersökningen visar att det finns kvar postkoloniala idéer som tar sig uttryck genom konstruktion av migranten som ”den andre” i materialet. / The purpose of this paper has been to study the journalistic portrayal of different groups in the news coverage regarding the measles outburst in the winter of 2017/2018, from a social constructionist perspective. The study has been carried out using critical discourse analysis. The results have been analyzed using postcolonial theory and theories about news logic and news as cultural community. Two main discourses emerged in the material, the public health discourse and the anti-vaccination discourse. A latent xenophobic discourse also emerged in the material. The study shows medial construction of “the other”, regarding two groups; the vaccination-objector and the migrant. The study does not show that the material is explicit xenophobic. However, the material clearly indicates a xenophobic discourse. Therefor the study shows that there are still postcolonial ideas, that are manifested through construction of the migrant as “the other” in the material.