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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Senior Research Fellow Anne Pesenacker, University College London, UK,
- Second opponent: Professor Tor Brynjar Stuge, The Arctic University of Norway (UiT)
- Third member and chair of the evaluation committee: Professor Marit Inngjerdingen, University of Oslo
Chair of the Defence
Professor Ludvig Andre Munthe, University of Oslo
Principal Supervisor
Professor Shuo-Wang Qiao, University of Oslo
Summary
This thesis is focused on characterization of gluten-reactive CD4+ T cells from coeliac disease (CeD) which is an autoimmune disease driven by consumption of dietary gluten present in wheat, barley and rye. Gluten-reactive CD4+ T cells are important players in the pathology of CeD that, when untreated, leads to mucosal inflammation and mucosal damage in the small intestine. The primary aim of the present work was to investigate the transcriptional heterogeneity of gluten-reactive CD4+ T cells at the single-cell level using RNA sequencing technology. Secondary aims were to (i) discover the role of CD161 receptor in gluten-reactive CD4+ T cells and to (ii) describe the broader significance of CD161 in CD4+ T cells.
The first part of this thesis is focused on single-cell RNA sequencing (scRNA-seq) of gluten-reactive CD4+ T cells. In the first article we described and quantified levels of index switching in multiplexed scRNA-seq libraries prepared from gluten-reactive CD4+ T cells and plasma cells isolated from untreated CeD patients. By utilising unique information about immune receptor expression, we were able to track the spread-of-signal across the samples. Overall, index switching significantly lowers the quality of the data and forces researchers to repeat sequencing process using platforms unaffected by index switching. In the second article we used scRNA-seq to determine which genes are differentially expressed in gluten-reactive CD4+ T cells in untreated CeD patients. Genes associated with gut-homing, T-cell receptor (TCR) co-signalling and cytokine production were upregulated in gluten-reactive CD4+ T cells. TCR reconstruction indicated in vivo clonal expansion of gluten-reactive CD4+ T cells.
The second part of this thesis is centred around the role of CD161 receptor in gluten-reactive CD4+ T cells as well as the significance of CD161 in CD4+ T cells in general. In the third article we used in vitro experiments to decipher the function of CD161 in the context of gluten-reactive CD4+ T cells. We coupled in vitro stimulation assays or in vitro proliferation assays with ligation of CD161 in expanded gluten-reactive CD4+ T cell clones. Although we observed surface downregulation of CD161 upon ligation with anti-CD161 monoclonal antibodies, we could not detect any measurable effect of CD161 ligation on cytokine production or proliferation. In the fourth article we described current knowledge about possible role of CD161 in CD4+ T cells. The study is focused on the inconsistencies of utilising CD161 as marker of IL-17-producing and marker of innate-like T cells. Moreover, we reviewed literature regarding putative co-signalling capacities of CD161 and concluded that this feature might be context-dependent.
Additional information
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