Le facteur de transcription ZEBRA (EB1) du virus d'Epstein-Barr joue un rôle essentiel dans l'initiation de l'infection lytique et la production virale. L'ubinucléine a été identifiée comme un partenaire cellulaire de ZEBRA, capable de l'empêcher de se fixer à ses séquences d'ADN cibles. Le rôle de l'ubinucléine dans la cellule demeure inconnu, ainsi que les conséquences de son interaction avec ZEBRA dans les cellules infectées par l'EBV. Notre travail a permis, d'abord, de mieux caractériser l'ubinucléine dans la cellule épithéliale en l'identifiant comme une protéine des jonctions serrées. L'ubinucléine a été proposée comme un nouveau membre de la famille des protéines NACos (nuclear and adhesion complex components) possèdant une double localisation, les noyaux et les jonctions des cellules. Afin de mieux comprendre son rôle dans la cellule épithéliale, nous avons étudié par une approche protéomique couplée à la spectrométrie de masse les partenaires de l'ubinucléine et identifié les protéines LYRIC et RACK-1. Nos résultats suggèrent que l'ubinucléine est impliquée dans différents processus biologiques tels que la régulation de la prolifération et de l'adhésion cellulaires. Enfin, dans les cellules épithéliales infectées par l'EBV, les fonctions de l'ubinucléine semblent dépendre de sa localisation cellulaire. Au niveau nucléaire, l'ubinucléine régule négativement le cycle lytique et la production de particules virales en empêchant ZEBRA et d'autres facteurs cellulaires de se fixer à leurs promoteurs de type AP-1. Lorsqu'elle est séquestrée dans les jonctions serrées, l'inhibition de ZEBRA est levée permettant ainsi le bon déroulement du cycle lytique du virus.

Le facteur de transcription IIH (TFIIH) joue un rôle crucial dans la transcription et dans la réparation de l’ADN. La sous-unité Tfb1/p62 (levure et humain) de TFIIH interagit avec de nombreux facteurs de transcription (p53, NFκB, TFIIEα) et de réparation (Rad2/XPG and Rad4/XPC) (1). La majorité des interactions avec Tfb1/p62 requiert le domaine d’homologie à la Pleckstrin (PH) localisé dans la région N-terminal de la protéine (2, 3). Ce domaine PH forme des complexes avec des domaines de transactivation acide provenant de protéines cibles impliquées dans la transcription et la réparation de l’ADN. De récentes études ont montré que Tfb1/p62 est une cible pour les protéines virales telles que la protéine VP16 du virus de l’herpès simplex (HSV) de type 1, la protéine E1 du virus du papillome humain (VPH) et la protéine EBNA-2 du virus Epstein-Barr (EBV) (4, 5). Ces protéines virales interagissent avec la sous-unité Tfb1/p62 par un domaine de transactivation acide suggérant une interaction similaire à ce qui est observé chez les facteurs de transcription humains comme p53. Ce mémoire présente une caractérisation structurelle et fonctionnelle du complexe formé par la protéine virale EBNA2 et la protéine humaine Tfb1/p62. L’analyse est faite en utilisant le titrage calorimétrique isotherme (ITC), la résonance magnétique nucléaire (RMN) et une expérience de transactivation chez la levure. Cette étude amène une plus grande compréhension des protéines impliquées dans les maladies comme le lymphome de Burkitt et le lymphome de Hodgkin qui sont souvent associées à l’infection à l’EBV (revue dans (6)) et caractérise une cible potentielle pour un antiviral. / The general transcription factor IIH (TFIIH) plays crucial roles in both transcription and DNA repair. Tfb1/p62 (yeast and human), one of the ten/eleven subunits of TFIIH, has been shown to interact with several important transcription (p53, NFκB, TFIIEα) and repair factors (Rad2/XPG and Rad4/XPC) (1). Most of the interactions with Tfb1/p62 require the Pleckstrin homology (PH) domain located at the amino-terminal end of the protein (2, 3). This PH domain in particular forms complexes with highly acidic domains from target proteins involved in both transcriptional activation and DNA repair. Recent studies has shown that the Tfb1/p62 subunit of TFIIH is also targeted by a number of viral proteins including the Herpes Simplex virus (HSV) protein VP16, the Human papillomavirus (HPV) protein HPV E1 and the Epstein-Barr virus (EBV) protein EBNA-2 (4, 5). These viral proteins interact with the Tfb1/p62 subunit via acidic domain which suggests that they are forming similar interactions as the one observed with human transcription and repair factors. This thesis provides a structural and functional characterization of the complex formed by the viral proteins EBNA2 and the human protein Tfb1/p62 subunit of TFIIH. The analysis is done using isothermal titration calorimetry (ITC), nuclear magnetic resonance (NMR) spectroscopy and a yeast activation assay. This study brings a greater understanding of proteins implicated in diseases such as the Burkitt’s lymphoma directly linked to an EBV infection (review in (6)) and shows a viable target for antiviral drug.

Firstly, the aims of the study were to investigate the influences of various factors, sex differences, Cytomegalovirus/Epstein-Barr virus (CMV/EBV) serostatus and vitamin D concentrations on respiratory illness incidence and immune function during the winter months in a student cohort of endurance athletes. In Chapter 3, the findings of the study concur with recent reports of illness incidence at major competitive games which indicate that female athletes may be more susceptible than their male counterparts to upper respiratory tract illness (URTI) symptoms and that lower oral-respiratory mucosal immunity may, in part, account for this. It was also found that previous coinfection with CMV and EBV might promote protective immune surveillance to lower the risk of URTI. In addition, it can be concluded that athletes with low plasma vitamin D concentrations may have a higher risk of URTI and suffer more severe symptoms when URTI is present. This may be due to impaired mucosal and systemic immunity as secretory immunoglobulin A (SIgA) secretion, cathelicidin levels and antigen-stimulated pro-inflammatory cytokine production appear to be increased by vitamin D-dependent mechanisms. A series of follow-up studies were also conducted to examine the effect of vitamin D on mucosal and systemic immunity in athletes. In Chapter 4, it was reported that the influence of vitamin D on circulating cytokines might be different in athletes compared with non-athletes and that both pro-inflammatory and anti-inflammatory cytokine production by multi-antigen stimulated whole blood culture were not influenced by 1,25-dihydroxy vitamin D (1, 25(OH)2D) iconcentrations within the normal healthy range. In Chapter 5, it was found that 5000 IU of vitamin D3 supplementation daily appears to have a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period. Nevertheless, the findings reported in Chapter 6 showed that there were no significant effects of vitamin D status and a 4-week period of daily high does vitamin D3 supplementation on salivary antimicrobial protein (AMP) responses to prolonged exercise. In conclusion, a series of studies in this thesis have demonstrated the influence of various factors (sex differences, CMV/EBV serostatus and vitamin D concentrations) on susceptibility to URTI among athletes. Moreover, it was suggested that vitamin D3 supplementation could have a positive effect on immune function and lead to decreased incidence of respiratory infections.

Epstein-Barr Virus (EBV), a ubiquitous herpesvirus that infects over 95% of the adult human population, has been implicated in the aetiology of a range of autoimmune diseases and tumours. In some of these disorders such as post-transplant B-cell lymphomas, EBV acts as a direct causal factor, in others, like Hodgkin's disease and nasopharyngeal carcinoma, it is an important co-factor. Additionally, EBV infection has been linked to several other diseases, most notably Multiple Sclerosis through positive correlation with the occurrence of Infectious Mononucleosis – a benign lymphoproliferative disease caused by primary EBV infection. The key feature of most EBV-disease associations is the ability of the virus to infect and transform human B- T- NK- and epithelial cells using a set of transcripts and proteins, some of which act as oncogenes. While it is evident that EBV viral load and gene expression may be correlated with the course of disease or even directly contributing to its pathology, the genetic determinants of EBV uptake, expression and its proliferative capacity remain unresolved. This project aimed to investigate the genetic determinants of EBV copy number and EBV latency gene expression for human B-cells immortalised by EBV in vitro and transformed into permanently growing lymphoblastoid cell lines (LCLs), as a model for early-stage EBV infection in naïve B-cells. LCL samples studied have been sourced from several different populations, the HapMap Project, the 1000 Genomes Project as well as British MRC-A family cohort. Methods used encompass quantification of viral expression and copy number using TaqMan and SybrGreen PCR techniques, followed by statistical association tests conducted using Plink, Merlin and MatrixEQTL. EBV QTLs identified by the assays were next subjected to a meta-analysis in GWAMA. Two most significant eQTLs were also selected for a replication experiment in an independent panel of newly generated LCLs and validated in peripheral blood B-cells sourced from the same donors. Multiple significant and suggestive expression and copy number QTLs were identified. However, most of these associations have not been replicated in more than a single cohort. The relatively small sample size of most cohorts tested as well as population structure posed a limitation. Some findings merit attention, particularly the presence of statistically significant viral eQTLs within or close to CSMD1 locus in two different cohorts, and finding of a significant EBV eQTL in a SNP associated with type 1 diabetes risk and located close to IL2RA, an immune-response gene harbouring multiple autoimmune disease risk loci. Suggestive associations were also identified in the 1000 Genomes Project samples by the copy number assay which resulted in the most robust test conducted. These encompassed an association to the PRDM9 locus as well as to a gene involved in TGF-β secretion. This is particularly interesting since TGF-β signal promotes lytic replication in EBV-infected B-cells and a consistent significant correlation between EBV lytic expression and increased viral copy number has been identified. In conclusion, although no significant association has been consistently replicated, the project provided several suggestive EBV QTL candidates with plausible biological links to EBV infection and replication, which could be studied further in independent experiments.

In der vorliegenden Arbeit wurden Lymphoproliferationen und maligne Non-Hodgkin-Lymphome der B-Zellreihe, die eine Infektion der Tumorzellen mit dem Epstein-Barr Virus aufwiesen, hinsichtlich ihres Immunphänotyps und ihrer zytogenetischen Aberrationen durch Fluoreszenz in-situ Hybridisierung charakterisiert. Von besonderer Bedeutung war es, durch eine detaillierte Analyse der klinischen Daten Vorerkrankungen/Zweiterkrankungen mit einer möglichen Immunsuppression zu identifizieren. Die erhaltenen Daten wurden mit denen EBV-negativer diffuser grosszelliger B-Zell Lymphome verglichen. In der Gewebe-Array-Technik konnten letztlich 69 Fälle detailliert charakterisiert werden. Von 53/69 (77%) dieser Lymphoproliferationen, die sämtlich eine EBV-Assoziation aufwiesen, konnten klinische Daten erhalten werden. Die detaillierte Analyse dieser Daten zeigte, dass in der grossen Mehrzahl der Fälle eine für eine EBV-Infektion prädisponierende Vor- bzw. Grunderkrankung vorlag (44/69 Fälle, 64%). Dabei handelte es sich in 9 Fällen um eine HIV-Infektion, in 12 Fällen um eine Post-Transplantations lymphoproliferative Erkrankung, in 19 Fällen um einen Zustand nach vorangegangener, therapierter Lymphomerkrankung und in vier Fällen um einen Zustand bei Methotrexatbehandlung oder vergleichbarer medikamentöser Immunsuppression. In neun Fällen war nachweislich keine zu einer möglichen Immunsuppression führende Grunderkrankung eruierbar; diese Tumoren, die bei Patienten mit einem Durchschnittsalter von 72,7 Jahren auftraten, entsprechen wahrscheinlich den in der Literatur beschriebenen „senilen“ EBV-assoziierten Lymphoproliferationen, bei denen eine durch das fortgeschrittenen Lebensalter bedingt reduzierte Fähigkeit des Immunsystems zu einer adäquaten Viruskontrolle diskutiert wird. Klinische Angaben, die auf eine mögliche Immunsuppression und damit auf eine mögliche EBV-Assoziation hindeuten, lagen zum Zeitpunkt der Vorstellung des Falles im Referenzzentrum bemerkenswerterweise nur in 26/69 Fällen (38%) vor.EBV-assoziierte Lymphoproliferationen und Lymphome gehören signifikant häufiger dem (immunhistochemisch definierten) non-GCB-Subtyp als dem GCB-Subtyp der DLBCL an (73% versus 37%; p<0,0001). Hier lag ein zusätzlicher interessanter Aspekt vor: EBV-assoziierte Lymphoproliferationen, die aufgrund ihrer Reaktivität der Tumorzellen für CD10 dem GCB-Typ zugeordnet worden waren, exprimierten nur in einer Minderzahl der Fälle (1 von 12; 8%) gleichzeitig auch BCL-6, ein Befund, der bei sporadischen, EBV-negativen DLBCL nur äußerst selten zu finden war (1 von 50; 2%). Weitere immunhistochemische Unterschiede zwischen EBV-assoziierten und EBV-negativen DLBCL lagen für die Expression des Aktivierungsmarkers CD30, der bei EBV-negativen DLBCL eher selten exprimiert wird, aber bei EBV-positiven DLBCL/-Lymphoproliferationen signifikant häufiger positiv ist, und auch für CD138 vor. Auch dieser Marker einer plasmazellulären Differenzierung war bei EBV-positiven DLBCL häufiger exprimiert, wohingegen die Expression von BCL-2 und BCL-6 in den Tumorzellen EBV-assoziierter LPD seltener war. Der häufigere non-GCB-Status, die vermehrte Expression von CD138 und die geringere Reaktivität für BCL-6 legen nahe, dass EBV-assoziierte DLBCL/Lymphoproliferationen offensichtlich aus B-Zellen bestehen oder hervorgegangen sind, die die Keimzentrumsreaktion bereits durchlaufen hatten. Die Analyse der interphasenzytogenetischen Daten und ihr Vergleich zu klassischen zytogenetischen Daten einer Kontrollgruppe von sporadischen DLBCL zeigte, dass chromosomale Bruchereignisse und auch eine TP53 Mutation (ausgewiesen durch die immunhistochemisch nachgewiesene Überexpression des Gens) nur bei denjenigen Fällen auftrat, die konventionell-morphologisch als DLBCL charakterisiert worden waren. Im Vergleich zur Kontrollgruppe wurde eine signifikant häufigere Rearrangierung von CMYC in EBV-assoziierten DLBCL gefunden; im Gegensatz hierzu waren Bruchereignisse im BCL2- und im BCL6-Locus ohne signifikanten Unterschied zur Kontrollgruppe. Als „Nebenbefund“ konnte in dieser Studie eine Infektion eines – offenbar primär nodalen – DLBCL vom immunoblastisch-plasmoblastischen Subtyp bei einem HIV-positiven Patienten durch das humane Herpesvirus 8 (HHV8) nachgewiesen werden. Diese Konstellation stellt insofern eine Rarität dar, da HHV8-positive DLBCL zumeist extranodal, z.B. in Form des sogenannten „Primären Effusions-Lymphoms“ (PEL) oder in Assoziation zu einer multizentrischen Castleman-Erkrankung bei HIV-positiven Patienten auftreten. / This study characterizes the immunophenotype and genetic aberrations (that were identified by fluorescence in situ hybridization) of Epstein-Barr-virus (EBV)-associated lymphoproliferations and non-Hodgkin lymphomas of B-cell origin.These data were compared with the data of EBV-negative diffuse, large B-cell lymphomas(DLBCL). Further, for the EBV-positive cases clinical data were evaluated.The clinical data showed that in most cases there was a specific kind of immunosuppression(e.g. previous tumors, HIV-infection, organ transplantation, iatrogenic immunosuppression by methotrexate) that correlates by cause with the EBV-infected lymphomas. In nine cases it has been proved that the patients had no kind of immunosuppression. These patients were all elderly (average 72,7 years) and their lymphomas and lymphoproliferations were classified as “ senile lymphoproliferations” (according to Shimoyama et al., 2006) where due to seniority a reduction of immunosystem is discussed. Results: The EBV-associated lymphoproliferations and lymphomas displayed a distinct immunophenotype. Compared to the de novo DLBCL they showed significantly more often the non-GCB-subtype. Interestingly, the EBV-positive lymphoproliferations which showed the CD10-positive GCB-subtype were only positive for bcl-6 in one case (8%), which is very unusual. The EBV-positive lymphoproliferations and lymphomas showed also significantly more expression of the activation protein CD30 and the plasma cell marker CD138 but less expression of bcl-2 and bcl-6. The oncogene MYC was significantly more often rearranged. As an additional result of this study a HHV8/EBV coinfection was found in an immunoblastic-plasmablastic DLBCL which occured in a cervical lymph node of a HIV-positive young male. This is a very rare finding because HHV8-positive DLBCL mainly occur at extranodal sites, e.g. as primary effusion lymphoma or in association with a multicentric Castleman disease, both often in the setting of immunodeficiency.

Die histologische Technik der Tissue-Microarrays ist eine sehr effiziente Methode, um eine große Anzahl auch heterogener Lymphome wie des Hodgkin-Lymphoms bei hohem Durchsatz unter homogenen Färbebedingungen zu untersuchen. Die vorliegende Arbeit konnte zeigen, dass ein Probeschnitt zur vorherigen Auswahl stanzwürdigen Tumorareals nicht nötig ist. Die so genannte Blindstanzung trug weniger als einen Prozentpunkt (0,9%) zum Verlust der auswertbaren Fälle bei. Dennoch war bei einzelnen Parametern (LMP1 und EBER) ein hoher Gewebeverlust zu beobachten. In einer Stichprobe von 2696 Stanzen waren es 24% (631 Stanzen) bedingt durch die Färbetechnik, aber auch durch unterschiedliche Vorbehandlungen und Originalfixationen des Probematerials. In dieser Studie wurden 1212 Fälle zur Immuntypisierung von Tumorzellen des klassischen und nodulär lymphozyten-prädominanten Hodgkin-Lymphoms untersucht. Die Fälle von c-HL wiesen eine häufige Expression von CD30- und CD15-Oberflächenmarkern und kaum B-Zell-Marker auf, während im NLP-HL die Expression in umgekehrter Häufigkeit vorlag. Diese bisher größte Untersuchung von T-Zell-Markern an H-/RS-Zellen, erstmalig auch an NLP-HL, ergab eine bis zu 6-fach höhere Frequenz in der NLP-HL bei häufigerer B-Zell-Marker-Expression. Die in der Literatur beschriebene Rangordnung der Expressionshäufigkeit von Oberflächenantigenen im c-HL (CD2 > CD4 > CD3 > CD5 > CD8) wurde bestätigt und wich nur in den Markern CD3 und CD5 ab: Perforin >> CD4 > CD5 > CD3 > CD8 > GranzymB > TIA-1 > CD7. Tzankov et al. [45] fanden in ihrer Untersuchung mit 259 c-HL-Fällen eine Häufigkeit von 5% T-Zell-Marker-Expression. Die vorliegende Arbeit mit 1147 untersuchten c-HL-Fällen kam zum Ergebnis einer deutlich höheren T-Zell-Marker-Expressionshäufigkeit von 20,1%. Der pathophysiologische Mechanismus der T-Zell-Marker-Expression ist bis heute noch unklar, könnte aber als eine alternative Signalkaskade zur Aufrechterhaltung des Zellzyklus unter geändertem Zellmilieu gedeutet werden. Ein weiterer Fokus dieser Arbeit betraf die Gruppe der Studienteilnehmer 60 Jahre und älter, um Hinweisen auf das „age-related“ EBV-associated Lymphom und der Rolle der Mikrosatelliten-Instabilität nachzugehen. So fand sich eine signifikante Häufung von Markern für eine EBV-Infektion (EBER, LMP1) in der Gruppe der über 60-Jährigen. Die Expression von DNA-Reparaturenzymen, deren Ausbleiben auf Mikrosatelliten-Instabilität gedeutet hätte, unterschied sich zwischen jüngeren und älteren Studienteilnehmern nicht.

Wing Y. Chan. / "March 2000." / Thesis (M.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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Xu Xuequn. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 100-125). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Epstein-Barr (EBV) Virus --- p.1 / Chapter 1.1.1 --- Virus Structure and Genome Structure --- p.1 / Chapter 1.1.2 --- Virus Types --- p.2 / Chapter 1.2 --- EBV Infection and malignancies --- p.3 / Chapter 1.2.1 --- In Vitro Infection --- p.3 / Chapter 1.2.2 --- Infection in the Natural Host --- p.8 / Chapter 1.2.3 --- Malignancies Associated with EBV --- p.11 / Chapter 1.3 --- T Cell-Mediated Immune Response to EBV --- p.16 / Chapter 1.3.1 --- The Pathway of Cell-Mediated Immune Response in Viral Infection --- p.16 / Chapter 1.3.2 --- Cell-Mediated Immune Response to EBV --- p.18 / Chapter 1.3.3 --- The Feature of CTLs Response to EBV --- p.20 / Chapter 1.4 --- CTLs to EBV Relevant MalignancieśؤApplications and Challenges --- p.21 / Chapter 1.5 --- HLA Polymorphisms and Strategy of Epitope-Based CTLs Therapy --- p.24 / Chapter 1.6 --- The Effect of HLA Polymorphism on EBV-Specific CTL Epitope Choice in Southern Chinese --- p.27 / Chapter 1.7 --- ELISPOT Assay 226}0ؤ Detection of CTLs Response --- p.32 / Chapter 1.8 --- Aim of This Study --- p.37 / Chapter Chapter 2: --- Material and Methods: --- p.39 / Chapter 2.1 --- Peptides --- p.39 / Chapter 2.2 --- PBMCs Preparations --- p.43 / Chapter 2.3 --- PBMC Counting and Cells Dilution --- p.43 / Chapter 2.4 --- Elispot Assay --- p.44 / Chapter 2.5 --- Counting the Spots --- p.45 / Chapter 2.6 --- Spots Forming Cells (SFC/106) and Positive Standard --- p.46 / Chapter Chapter 3: --- Results --- p.47 / Chapter 3.1 --- Validation of ELISPOT assay methodology --- p.47 / Chapter 3.2 --- CTLs Response to Each Epitope in the Population --- p.55 / Chapter 3.2.1 --- Positive Response to A11 Restricted and Mutant Epitopes in the Population --- p.55 / Chapter 3.2.2 --- Positive Frequencies of A2 Restricted Epitopes in the Population --- p.63 / Chapter 3.2.3 --- Positive Frequencies of Other HLA Allele Restriction Peptides --- p.70 / Chapter 3.3 --- CTLs Response Frequencies Categorized by Proteins --- p.74 / Chapter 3.3.1 --- "CTLs Response to LMP1, LMP2, EBNA1 Epitopes" --- p.74 / Chapter 3.3.2 --- "CTLs Response to EBNA2, EBNA-LP Epitopes, EBNA3 Epitopes" --- p.75 / Chapter 3.3.3 --- CTLs Response to LYTIC Epitopes --- p.79 / Chapter 3.4 --- Summary --- p.80 / Chapter Chapter 4: --- Discussion --- p.82 / Chapter 4.1 --- Discussion of A11 Restricted Epitopes --- p.82 / Chapter 4.2 --- Discussion of A2 Restricted Epitopes --- p.86 / Chapter 4.3 --- Discussion of Other HLA Restricted Epitopes --- p.89 / Chapter 4.4 --- "Discussion ofLMPl, LMP2, EBNA1 Epitopes" --- p.92 / Chapter 4.5 --- "Discussion of EBNA2, EBNA3, and EBNA-LP epitopes" --- p.96 / Chapter 4.6 --- Discussion of LYTIC Epitopes --- p.96 / Chapter 4.7 --- Discussion of Summary --- p.98 / Chapter Chapter 5 --- Conclusion --- p.99 / Chapter 6 --- Reference --- p.100 / Chapter 7 --- Appendix --- p.126 / Chapter 7.1 --- "Appendix 1, raw data of Elispot assay on CTLs response to EBV relevant epitopes m Hong Kong donors" --- p.126 / Chapter 7.2 --- "Appendix 2, frequencies from highest cell number wells of the peptides (SFC/106)" --- p.126 / Chapter 7.3 --- "Appendix 3, typical Elispot assay figure " --- p.126

A comprehensive immunohistochemical study was carried out to investigate the phenotypes and prevalence of intraepithelial lymphocytes in NPC samples semi-quantitatively. CD25+/FOXP3+ T-cells were highly prevalent in primary NPCs, suggesting the presence of the immunosuppressive Tregs in tumor microenvironments. The low abundance of CD4+ T-cells, and the positive correlation between FOXP3 and CD8 staining in NPC samples imply that CD8+FOXP3+ Tregs may be present and play role in the suppression of anti-tumor immune response in NPC patients. The involvement of chemokine in the migration of tumor-infiltrating lymphocytes was studied. Chemokine ligand 20 (CCL20) was overexpressed in all EBV-positive NPC cell lines and xenografts compared to EBV-negative NPC, and immortalized normal nasopharynx epithelial cell lines. The presence of CCL20 was also found in primary tumors but not in normal epithelium. Furthermore, the ability of LMP1 to upregulate CCL20 expression in epithelial cells indicates that EBV may induce the production of chemokine involved in lymphocyte migration. / Epstein-Barr virus (EBV) is invariably associated with the development of nasopharyngeal carcinoma (NPC). Although the association of EBV and cancer has been reported for about four decades, it is still not clear how EBV latent infection contributes to the transformation of nasopharyngeal epithelial cells. The aims of this study are to identify EBV-regulated cellular genes and pathways and to determine the potential role of EBV in the modulation of anti-tumor immune responses in NPC. / In summary, EBV plays critical roles in the development of NPC by regulation of multiple cellular genes and pathways such as the Notch signaling cascade, and modulation of anti-tumor immune responses through the induction of chemokine important in migration of immune cells. / Notch signaling pathway functions in diverse cellular processes such as proliferation, apoptosis, adhesion, and epithelial to mesenchymal transition. In the current study, aberrant expression of activated Notch1 receptor (NICD), Notch ligand (Jagged1), negative regulator of Notch ( NUMB) and Notch downstream effector (HEY1) was detected in NPC cell lines and xenografts. Overexpression of NICD, Jagged1 and HEY1 proteins was also commonly found in primary tumors of NPC. / Transfection of Jagged1 to normal nasopharynx epithelial cells resulted in increased cell proliferation. Moreover, EBERs, which is abundantly expressed in EBV-positive NPC tumors, was capable of inducing the expression of Jagged1 in epithelial cells. The current data shows that Notch signaling pathway is aberrantly activated by the deregulated expression of multiple Notch components in NPC. The induction of Jagged1 by EBERs also implies the potential role of EBV in the activation of Notch signaling cascade in NPC. / Using high-density oligonucleotide microarray, expression profiles of EBV-infected NPC cell lines, HK1+EBV and HONE1+EBV, and their uninfected counterparts, HK1 and HONE, were generated. From the microarray results, six EBV-upregulated (JDP2, IL8, ATP6V0E2L, PLAP, PIK3C2B and AKR1B10 ) and three EBV-downregulated genes (BACE2, PADI3 and MMP1) were identified in both HK1 and HONE1 cells upon EBV latent infection. One hundred and thirty-eight and seventy-six genes were also found to be differentially modulated by EBV in HK1 and HONE1 cells, respectively. This study shows that cellular genes involved in wide range of biological processes and cellular functions are differentially regulated by EBV, which suggest that EBV modulates multiple pathways and processes during NPC tumorigenesis. / Hui, Wai Ying. / Adviser: Kw Lo. / Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0806. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 166-204). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / School code: 1307.