An in vitro cell and organ culture system for the study of human arthrotropic viruses was established to determine the permissiveness of joint cells and tissue to five strains of rubella virus (RV), adenovirus type 2 (Ad) and human parvovirus (B19). A semi-continuous line of fetal chondrocytes (FC) and primary synovial membrane/cartilage (SMC) cells were used to investigate virus/joint cell interactions. In addition, the SMC cells were used to determine the ability of a virus to establish a persistent infection in cells of joint origin. Intact joint tissue containing both synovial membrane and cartilage was also infected to determine the ability of the viruses to replicate in non-dividing cells and also their invasive capability in the presence of an extracellular matrix. Results showed that all RV strains and Ad were able to replicate in FC, SMC cells and intact joint tissue. The only exception to this was that replication of RV strain Cendehill was not detected in joint tissue. In contrast, there was no indication, by either DNA-DNA hybridization or immunoperoxidase staining, that B19 was able to replicate in SMC cells. Most importantly, the behaviour of the rubella strains in this model was found to correlate with the clinical data concerning the incidence of complications associated with rubella infection or vaccination. This suggests that arthritogenicity is related to the ability of a particular virus to infect and persist in joint tissue and establishes the in vitro model as a useful system to evaluate the arthrotropicity of future rubella vaccines. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

Results of the above studies thus suggested that immune dysregulation in SLE result in derangement of a spectrum of inflammatory mediators leading to possible multiple organs auto-inflammatory damages. However, the exact etio-pathogenic mechanism could not simply be explained by these phenomena. Infection has been invoked as an underlying etiology or trigger for the induction of autoimmune disease. Epstein-Barr virus (EBV) possesses multiple features that characterise its involvement in initiating or perpetuating SLE disease. Several research groups demonstrated that the peripheral blood EBV DNA load is significantly higher in SLE patients, yet cell-free viral DNA was also reported in other EBV-associated diseases such as nasopharyngeal carcinoma (NPC) and certain lymphomas, suggesting that relatively little is known about its biology and dynamic distribution in the blood circulation. In the second part of our study, we examined the cell-free and cell-associated distribution profile of EBV DNA load in SLE. Our data showed that the distribution of EBV DNA in the cell-free and cell-associated compartments exhibited a heterogeneous pattern in SLE patients. Contrary to the exclusive presence of circulating cell-free EBV DNA in NPC patients, both cell-free and cell-associated EBV DNA were detected in some SLE patients, while in others, no EBV DNA was measurable in either blood compartments. The level of cell-associated EBV viral load was significantly higher in SLE patients with active disease than those who presented with milder disease activity. This phenomenon indicated a possible association of EBV viral infection with the level of immune competence in SLE patients. It has been reported that EBV encodes proteins which shares significantly homology sequence with human IL-6, IL-8, IL-10, IL-12 and colony-stimulating factor (CSF)-1. This proposition brought our attention to the immune perturbation by EBV on the cytokine balance, possibly constitute in part, to the immune dysregulation and Th1 and Th2 dichotomy in SLE exacerbation. (Abstract shortened by UMI.) / The first section of this research study aimed to explore the messengers that influence Th1/Th2 cells differentiation, development, effector functions and hence their plausible contribution in SLE immunopathogenesis. We focused on studying the expression of cytokine and chemokine milieu that directs the traffic of T lymphocytes; co-stimulatory molecules in the activation of T lymphocytes; transcription factors T-bet and GATA-3 in regulating the differentiation of Th1 and Th2 cell lineage. We also investigated the involvement of the lymphocyte subpopulation, Th17 in the auto-inflammatory axis of SLE exacerbation. / Lit, Choi Wan. / Advisers: Christopher W.K. Lam; Y.M. Dennis Lo. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3358. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 203-235). / 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. / Abstracts in English and Chinese. / School code: 1307.