published_or_final_version / Community Medicine / Master / Master of Public Health

Thesis (M.P.H.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 64-67).

Thesis (Ph.D.)--Tufts University, 2005. / Adviser: Simin Nikbin Meydani. Submitted to the School of Nutrition Science and Policy. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Infection of people with human immunodeficiency virus (HIV) as well as LPBM5 infection in mice results in progressive deterioration of the immune system in the majority of untreated hosts. Peptide immunotherapy has been shown to be effective in the stimulation or immunoregulation of T-helper 1 (TH1) and T-helper 2 (TH2) response subsets. In murine acquired immunodeficiency syndrome (AIDS), TH1 deficiency enables the host to be susceptible to coxsackievirus infection, inducing cardiopathology in a short period. T-cell receptor (TCR) Vβ8.1 peptide, a 16-mer peptide containing the entire CFR1 segment and part of the FR2 region of human Vβ8, showed both an immunoregulating and immunostimulating effect in murine AIDS. TCR Vβ8.1 peptide acts on T cells promoting interleukin-2 production and therefore enhancing a cellmediated immune response. It retarded development of cardiopathology due to coxsackievirus infection. Retrovirus infected mice treated with the peptide showed a longer life span than the nontreated retrovirus infected animals.

CAR (for C&barbelow;oxsackievirus and A&barbelow;denovirus R&barbelow;eceptor) is a novel member of the Ig superfamily, which has recently been identified as a high affinity receptor for both Coxsackievirus and certain adenovirus (AV) serotypes. Virus bound by CAR is believed to be passed to integrins which bind an RGD (Arg-Gly-Asp) sequence in the viral penton base protein and act as secondary receptors responsible for virus internalization. / Recent studies have shown that, in integrin-expressing cells, CAR-mediated AV uptake does not require the cytoplasmic (CP) domain of CAR, presumably because virus bound to the CAR extracellular (EC) domain can be passed to integrins for subsequent internalization. It has however also been reported that CAR can directly mediate AV uptake in the absence of penton base RGD-alphav integrin interactions. I therefore attempted to determine whether the CP domain of CAR is required for CAR-mediated AV uptake in cells which do not express integrins, or in which integrin function has been blocked by RGD-containing peptide. / As CAR is the primary AV receptor and integrins are secondary AV receptors I investigated the possibility that these proteins associate in a functional complex in the cell membrane. (Abstract shortened by UMI.)

Lic.-avh. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 3 uppsatser.

Indiana University-Purdue University Indianapolis (IUPUI) / Enteric viruses are among the most common infectious human viruses worldwide, causing an estimated 10-15 million infections per year in the United States. Among enteric viruses, Coxsackievirus is commonly isolated and can lead to the development of meningitis, encephalitis, pancreatitis, and hepatitis. Furthermore, Coxsackievirus B3 is the primary cause of viral myocarditis and can lead to pleurodynia, with nearly 40,000 symptomatic cases reported in the United States each year. The enteroviral ssRNA genome contains a 5’ untranslated region (5’UTR) which consists of two structural components, the cloverleaf and the internal ribosome entry site (IRES), both shown to be integral to viral success. Additionally, the viral genome encodes four structural VP proteins as well as 11 non-structural proteins. Polymorphisms found within the CVB3 population have been linked to viral virulence. Here, we compare two CVB3 Nancy variants to elucidate the downstream effects observed in response to mutations found in the CVB3 genome. Implementing our novel oral inoculation model, we aimed to determine the impact mutations found in the 5’UTR and VP regions exert on viral pathogenesis. We also aimed to delineate the in vitro effects of the observed mutations. We investigated the role mutations found in the structural regions played in virus host cell attachment, in vitro cell viability, and replication. Our work has further confirmed the relevance and impact of mutations found in the VP region of the CVB3 genome.

No description available.

Les Entérovirus humains du groupe B (EV-B) et plus spécifiquement les virus Coxsackie B sont considérés comme une cause majeure des myocardites infectieuses aigues et chroniques dont 10% peuvent évoluer vers la cardiomyopathie dilatée (CMD). Les mécanismes moléculaires viraux impliqués dans la progression de la myocardite aiguë vers le stade de la CMD ne sont pas élucidés.L’analyse par séquençage NGS a montré chez 8 (33%) des 24 patients atteints de CMD inexpliquée l’existence de populations majoritaires tronquées de 19 à 50 nucléotides associées à des formes virales minoritaires complètes. La proportion de populations tronquées s’est révélée négativement corrélée au ratio ARN+/ARN- et à la charge virale. Des études immuno-histologiques et par hybridation in situ des tissus cardiaques ont montré que le clivage de la dystrophine était uniquement retrouvé dans les cardiomyocytes infectés par les EV-B. Pour étudier les activités de réplication des populations d’EV-B persistants, un réplicon (CVB3-emGFP) a été généré à partir d’une souche cardiotrope (CV-B3/28). La transfection d’ARN de synthèse complets et tronqués (d50) dans des cultures de cardiomyocytes humains primaires a mis en évidence des mécanismes de recombinaison et/ou de trans-complémentation entre ces 2 formes virales induisant de faibles activités de réplication.Nos résultats démontrent l’existence de mécanismes de coopération moléculaire entre des populations d’EV-B tronquées et complètes qui pourraient expliquer la mise en place du mécanisme de persistance virale observée au cours de la phase clinique de CMD. Ces résultats pourraient contribuer au développement de nouvelles stratégies thérapeutiques pour prévenir et traiter les infections cardiaques à EV-B. / Enteroviruses group B (EV-B) and more specifically Coxsackievirus B are recognized as major causes of acute and chronic infectious myocarditis, which 10% may progress towards dilated cardiomyopathy (DCM). Viral molecular mechanisms involved in the progression from acute myocarditis to the clinical stage of DCM remain unknown.Deep sequencing analysis showed in 8 (33%) of 24 unexplained DCM patients the existence of major CVB3 populations with deletions of 19 to 50 nucleotides associated with a minority of complete viral forms. The proportion of deleted viral populations was negatively correlated with RNA+/RNA- ratio and the viral load levels. Immuno-histological and in situ hybridization assays of DCM cardiac tissues demonstrated that the cleavage of dystrophin was found only in cardiomyocytes infected with EV-B. To study the replication activities of persistent EV-B populations, a replicon (CVB3-emGFP) was generated from a cardiotropic strain (CV-B3/28). Transfection of synthesized complete and truncated (d50) viral RNAs in primary human cardiomyocytes cultures revealed mechanisms of recombination and / or trans-complementation between these two viral forms inducing low replication activities.In conclusions, our original results demonstrated the existence of new molecular mechanisms of cooperation between EV-B deleted and complete viral populations that could explain the development of a viral persistence mechanism observed during the clinical phase of DCM. These findings may contribute to the development of new therapeutic strategies to prevent and treat persistent heart EV-B infections.

Les pathogènes neurotropiques représentent une banque d’outils biologique afin de cibler spécifiquement le système nerveux central (SNC), pour son étude mais aussi dans l’optique d’une thérapie. Parmi eux, l’adénovirus canin de type 2 (CAV-2) est un vecteur prometteur pour cibler le SNC. CAR a été principalement étudié en tant que récepteur viral. Cependant, plusieurs études montrent que CAR est essentiel dans le développement du cœur ainsi que du système lymphatique. De manière intéressante, CAR est fortement exprimé pendant le développement du SNC, suggérant un rôle dans l’établissement des réseaux neuronaux. Dans ce travail, nous avons confirmé que CAR est lié aux mécanismes d’endocytoses et au trafic intracellulaire. L’endocytose de CAR est ligand dépendant. La partie intracellulaire de CAR régule son endocytose. Nos données suggèrent que CAR est l’unique récepteur pour CAV-2. Le présent travail de recherche montre aussi que CAR ne semble pas participer à la formation du SNC. En revanche, au niveau du SNC mature, CAR est impliqué dans la plasticité synaptique, dans la neurogénèse adulte et participe à l’homéostasie des synapses, mécanismes impliqués dans les processus mnésiques. / The coxsackievirus and adenovirus receptor (CAR) is a single-pass transmembrane protein belonging to the CTX subfamily of the immunoglobulin superfamily. CAR has been extensively studied as a viral receptor for coxsackie B viruses and some adenoviruses (AdVs). CAR is essential for the development of the cardiovascular and lymphatic system. Interestingly, CAR is highly expressed in the developing brain and has been hypothesized to regulate the establishment of the neuronal networks. In my PhD work, I showed that CAR can be link to the endocytic pathways and intracellular trafficking. CAR endocytosis is ligand-dependent and is regulated by CAR intracellular domain (ICD), suggesting strongly that CAR is most likely the unique receptor for canine adenovirus type 2 (CAV-2). Moreover, we demonstrated that CAR depletion in the developing brain did not significantly perturb brain development. In the healthy adult brain, CAR is relatively abundant and we demonstrated that CAR loss of function affected hippocampal plasticity, adult neurogenesis and synapse homeostasis, which affect cognition.