Hybrid Peptide-Specific T Cells Incite Islet Inflammation And Autoimmune Diabetes
2022-04
Loading...
View/Download File
Persistent link to this item
Statistics
View StatisticsJournal Title
Journal ISSN
Volume Title
Title
Hybrid Peptide-Specific T Cells Incite Islet Inflammation And Autoimmune Diabetes
Authors
Published Date
2022-04
Publisher
Type
Thesis or Dissertation
Abstract
Autoimmune diabetes (AD) is a disease characterized by T cell-mediated destruction of the insulin-producing β cells within the islets of Langerhans of the endocrine pancreas. Upon recognition of β cell-specific autoantigen, self-reactive T cells of various specificities expand and migrate to pancreatic islets. Recently, a hybrid peptide derived from the insulin C-chain and chromogranin A (InsC-ChgA) was identified as the cognate antigen for the non-obese diabetic (NOD) mouse-derived diabetogenic BDC-2.5 CD4+ T cell clone, suggesting InsC-ChgA-specific T cells may contribute to disease. Epifluorescent microscopy of pancreatic islets is one approach by which islet T cell inflammation can be assessed in the course of disease altering therapies targeting InsC-ChgA-specific cells, yet most analytical techniques rely upon cumbersome manual estimation of islet infiltration. Importantly, little is known regarding the pathogenicity of InsC-ChgA-specific CD4+ T cells in NOD mice and how selective inhibition of these cells impacts cross-sectional T cell infiltrate area within the pancreatic islets. Here, we first describe a novel approach to achieve rapid, automated, unbiased, and quantifiable data regarding the distribution of islet infiltrating CD4+ and CD8+ T cells in NOD mice. We demonstrate the accurate detection of islet borders using convex hull islet modeling and quantification of T cell infiltrate by writing a macro using the freeware ImageJ. With this method, we assessed CD4+ and CD8+ T cell inflammation within the islets of different age groups of NOD mice progressing towards AD. As proof of technique, we identified significantly more T cell infiltration within convex hull-defined islets of non-diabetic 13-week and 17-week diabetic NOD mice compared to 4-week mice. Second, we focused on the InsC-ChgA-specific CD4+ T cell response in NOD mice and show rapid activation and expansion in neonates. We found that expansion of InsC-ChgA-specific cells requires early interactions with XCR1+ type 1 conventional dendritic cells, and InsC-ChgA-specific cells are clonally restricted with bias towards TRBV15 usage. We also show that adoptive transfer of polyclonal InsC-ChgA-specific cells into NOD.Rag1-/- mice induces AD. Further, spontaneous disease can be suppressed through weekly administration of an InsC-ChgA:I-Ag7-specific monoclonal antibody (mAb). Using the convex hull approach for quantification of T cell infiltration, we identified a substantial decrease in both CD4+ and CD8+ intra-islet infiltration in the nominally pre-diabetic period following InsC-ChgA:I-Ag7 mAb treatment. This thesis describes a novel methodology for the quantifiable assessment of T cell islet infiltration in NOD mice. Additionally, the data here establish the pathogenicity of InsC-ChgA-specific CD4+ T cells, and that immune responses to InsC-ChgA antigen are both necessary and sufficient for AD induction. These results form a framework for future interrogation of other hybrid peptide-specific T cell contributions to AD development in both mice and humans.
Description
University of Minnesota Ph.D. dissertation. April 2022. Major: Microbiology, Immunology and Cancer Biology. Advisor: Brian Fife. 1 computer file (PDF); xiii, 194 pages.
Related to
Replaces
License
Collections
Series/Report Number
Funding information
Isbn identifier
Doi identifier
Previously Published Citation
Suggested citation
Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.