dc.contributor.author | Furlong, Suzanne Joy | |
dc.date.accessioned | 2012-09-11T11:39:19Z | |
dc.date.available | 2012-09-11T11:39:19Z | |
dc.date.issued | 2012-09-11 | |
dc.identifier.uri | http://hdl.handle.net/10222/15491 | |
dc.description.abstract | Thy-1 is a glycosylphosphatidylinositol-anchored protein that is expressed on murine T lymphocytes and is involved in T cell-mediated immune responses. In the presence of costimulatory signals, monoclonal antibody (mAb)-induced signaling through Thy-1 is associated with hallmarks of T cell activation, including IL-2 production and T cell proliferation. Thy-1-induced signaling promotes cytotoxic effector molecule expression, but is unable to trigger delivery of the lethal hit to target cells, suggesting that Thy-1 provides an incomplete T cell receptor (TcR)-like signal. However, the effect of Thy-1 signaling on cytokine production and the development of T helper (Th) cell phenotypes (Th1, Th2, Th17) remains unclear. The purpose of this work was to further our understanding of Thy-1-mediated signal transduction and the role that Thy-1 plays in the development of effector T cell responses. I found that, in the context of costimulatory signals, anti-Thy-1 mAb induced significantly less IL-2 production, CD25 expression and T cell proliferation than anti-TcR? mAb. Several key signaling molecules, including protein tyrosine kinases, zeta chain-associated protein-70 and extracellular signal-regulated kinase were activated with delayed kinetics during Thy-1-mediated T cell activation. The delayed signaling kinetics resulted in the delayed acquisition of cytotoxic effector function and also delayed delivery of the lethal hit to target cells. Interestingly, Thy-1-mediated signaling induced significantly more IL-17 and IL-4 synthesis and less IFN-? synthesis in comparison to TcR-mediated signaling. Moreover, Thy-1-activated CD4+ T cells produced high levels of IL-17 and IL-4 but minimal IFN? when restimulated with anti-Thy-1 mAb or anti-TcR? mAb with or without costimulatory signals. The unique ability of Thy-1 signaling to induce IL-17 production correlated with the expression of the Th17 lineage-specific transcription factor, retinoic orphan receptor gamma t. These observations show that Thy-1 signaling differs from TcR signaling in its ability to induce Th cell cytokines. Taken together, my findings show that Thy-1 signaling can provide the full TcR-like signal required for both the differentiation and triggering of Th cells and cytotoxic T lymphocytes, albeit with delayed kinetics in comparison to TcR signaling. They also suggest that Thy-1 signaling may be important in the development of Th2 and Th17 responses. | en_US |
dc.language.iso | en | en_US |
dc.subject | Signal Transduction | en_US |
dc.subject | T cells | en_US |
dc.subject | Dendritic Cells | en_US |
dc.subject | T cell Activation | en_US |
dc.subject | Cytokine Production | en_US |
dc.subject | IL-4 | en_US |
dc.subject | IL-17 | en_US |
dc.subject | Cytotoxic Effector Function | en_US |
dc.title | Thy-1 Signaling in T cells is Weaker and Has Delayed Signaling Kinetics, Promotes Delayed Acquisition and Triggering of Cytotoxic Effector Function, and Preferentially Promotes IL-17A and IL-4 Production in Comparison to TcR Signaling | en_US |
dc.date.defence | 2011-04-25 | |
dc.contributor.department | Department of Microbiology & Immunology | en_US |
dc.contributor.degree | Doctor of Philosophy | en_US |
dc.contributor.external-examiner | Dr. George Carayannoitis | en_US |
dc.contributor.graduate-coordinator | Dr. Roy Duncan | en_US |
dc.contributor.thesis-reader | Dr. Robert Liwski | en_US |
dc.contributor.thesis-reader | Dr. Brent Johnston | en_US |
dc.contributor.thesis-supervisor | Dr. David Hoskin | en_US |
dc.contributor.ethics-approval | Received | en_US |
dc.contributor.manuscripts | Not Applicable | en_US |
dc.contributor.copyright-release | Not Applicable | en_US |