"January 2002" Bibliography: leaves 204-230.

"January 2002" / Bibliography: leaves 204-230. / vii, 230, [31] leaves : ill. (chiefly col.), plates (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Molecular Biosciences, 2002

Not available / text

A double immunolabelling technique was developed to study microscopically the interactions between CD4, CD45 and the T cell receptor on the surface of rat T cells induced by the phenomenon of co-capping. It was found that both CD4 and CD45 passively co-cap with the actively capped T cell receptor, that the T cell receptor and CD45 passively co-cap with CD4, but that neither CD4 nor the T cell receptor co-cap with CD45. Co-crosslinking and active capping of CD45 with either the T cell receptor or CD4 prevented CD4 or the T cell receptor respectively, from passively co-capping. These experiments were extended to study the effects of particular antibody crosslinking conditions on T cell proliferation and tyrosine phosphorylation. A correlation was found to exist between receptor distribution and the effects of particular antibody combinations on proliferation and tyrosine phosphorylation. The significance of this with respect to T cell activation is discussed. Finally, an observation is reported concerning the failure of some cell lines to cap antibody-crosslinked surface molecules. Preliminary investgations into the nature and extent of the phenomenon are described.

The study of B and T cell receptor repertoires from high throughput sequencing is a recent development that allows for unprecedented resolution and quantification of the adaptive immune response. The immense diversity and long tailed distribution of these repertoires has up until now limited such studies to expanded clonal signatures or to analysis of imprecise signals with limited dynamic range collected by techniques such as radioactive and fluorescent labeling. This thesis presents a number of quantitative methods to characterize the repertoire and examine the questions of sequence diversity and inter-repertoire divergence of T cell repertoires. These approaches attempt to accurately parametrize the inherent distribution of T cell clones drawing from statistical tools derived from ecological literature and information theory. The methods presented are applied to T cell analyses of various tissue compartments of the human body, including peripheral blood mononucleocytes, thymic tissues, spleen, inguinal lymph nodes, lung lymph nodes and the brain. A number of applications are explored with strong implications for translational use in medicine. Novel insights are made into the mechanism of maintenance and compartmentalization of na{\"i}ve T cells from human donors of many different ages. Diversity and divergence of the tumor infiltrating sequence repertoire is measured in low grade gliomas and glioblastomas from cancer patients, and potential sequence based biomarkers are assessed for studying glioma phenotype progression. A careful investigation of the immune response to allogeneic stimulus reveals the effect of HLA on sequence sharing and diversity of the alloresponse, and quantifies for the first time using sequence data the fraction of T cells in a repertoire that are alloreactive. The use of repertoire sequencing and mathematical models within immunology is a new and emerging concept within the rapidly expanding field of systems immunology and will undoubtedly have a profound impact on the future of immunology research. It is hoped that the tools presented in this thesis will give insight into how to quantitatively explore the breadth and depth of the T cell receptor repertoire, and provide future directions for TCR repertoire analysis.

"October 2001" Amendments (4 leaves) inserted inside back cover. Includes bibliographical references (leaves 215-266)

published_or_final_version / Paediatrics and Adolescent Medicine / Doctoral / Doctor of Philosophy

The recognition of MHC-peptide ligands by the T cell receptor (TCR) is central to the induction of the adaptive immune response. This thesis describes the development of a bioassay for TCR recognition which was then used to undertake a molecular analysis of the TCR/MHC-peptide interaction. 1. A TCR-CD3ϛ chimeric receptor was stably expressed in the cell line RBL-2H3 to give the transfectant RBL-008. RBL-008 was shown to exhibit MHC-restricted peptide-specific responses to both cellular and multimerised recombinant HLA-A2-pol peptide targets (Chapter 3). 2. By competitively inhibiting the response of RBL-008 to HLAA2 pol complexes with monovalent soluble recombinant MHCpeptide complexes it was confirmed that the TCR makes significant contact with both the MHC and peptide parts of its ligand. Furthermore it was found that only a few peptides in a random mixture can prevent contact between the TCR and HLA-A2. This has implications for positive selection since it supports evidence suggesting that some TCRs can be selected on a wide range of unrelated peptides (Chapter 4). 2. The bioassay was used to examine the flexibility of TCRpeptide interactions using a panel of variant peptides designed on the basis of the previously published HLA-A2-pol peptide structure (Chapter 5). Several variant peptides were recognised by the TCR and interestingly one of these altered peptide ligands was actually recognised better than the index peptide, raising the prospect of designing 'improved epitopes'. 3. By mutating the β chain of TCR-CD3ϛ chimeric receptor it was shown that allelic variation in the TCR genes can have a significant effect on antigen recognition and may therefore be disease susceptibility candidates genes (Chapter 6). 4. The structural relationship between the V and C domains of the TCR was examined and found to be of considerable functional significance since disruption of this relationship resulted in loss of expression of the TCR-CD3ϛ receptor.

No description available.

Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted.