nPOD Autoimmunity Working Group
The Autoimmunity Group operates under the premise that the resident immune cells at the site of autoimmune attack within the pancreas are key to understanding the fundamental pathways of disease development. The major goal of this working group is to elucidate the mechanisms by which autoreactive T cells and B cells, as well as other APC, contribute to destruction of pancreatic beta cells and development of type 1 diabetes (T1D). Investigators participating in the group share nPOD tissues, cells, reagents, cell lines, clones, protocols, and data to optimize the amount of information gained from precious nPOD donor materials (spleen, pancreatic draining lymph nodes, and islet-infiltrating lymphocytes) and to synergize the efforts of the nPOD and broader scientific community.
The mission and work of the group includes efforts aimed at characterizing pathogenic phenotypes of specific T and B cell subsets (including those reactive to specific antigens), defining T cell (TCR) and B cell (BCR) antigen receptor repertoires of specific cell subsets, and determining antigen specificity. In addition, there is an infrastructure in place to share reagents (e.g., conjugated antigens, tetramers, vectors encoding an islet-reactive TCR, etc) and fresh and frozen cell material (e.g., T cell lines/clones) to evaluate the quality and reproducibility of investigator assays. These efforts will provide critical insight into developing biomarkers as well as robust therapies to cure and prevent T1D.
The Autoimmunity group consists of 5 subgroups listed below. Individual subgroups have monthly to quarterly conference calls to design experiments and share data and ideas. The entire group typically has a conference call twice a year as well as a face-to-face meeting at the annual nPOD conference to report activities from the individual subgroups and to discuss further possible collaborations.
1. Antigen specific T cells (Group leader – Sally Kent, University of Massachusetts School of Medicine)
The antigen specific T cell group aims to isolate and characterize CD4 and CD8 T cells reactive to known islet-associated antigens as well as as-of-yet-undescribed islet antigens. Antigen-specific T cells will be identified and evaluated for T cell phenotype, proliferation and cytokine secretion upon antigen stimulation, and TCR usage by T cell cloning, multimer staining analysis (i.e. tetramers, Qdots), CFSE-proliferation assay, Elispot assay, cell surface marker analysis using Flow-cytometry and CyTOF, gene expression analysis using Fluidigm and RNA sequencing, and TCR sequencing.
2. T cell receptors (Group leader – Maki Nakayama, University of Colorado SOM)
Merits of identifying TCR repertoires specific for T1D development are three-fold. First, TCR sequences could be used as biomarkers to recapitulate levels of islet-specific T cells in peripheral blood. Second, by tracing TCR sequences between cell subsets and different organs, we are able to illustrate how autoreactive T cells differentiate, expand, and activate to target antigens. Finally, identification of TCR sequences allows one to define antigens to be recognized. For these purposes, the TCR subgroup aims to identify TCR sequences as well as TCR alpha & beta pairs of T cells in the pancreatic islets, draining lymph nodes, spleen, and peripheral blood obtained from T1D patients.
3. Regulatory T cells (Group leaders – Todd Brusko, University of Florida and Jeffrey Bluestone, University of California, San Francisco)
The goals of Treg subgroup are to characterize Tregs in T1D patients for phenotypes, antigen specificity, differentiation, and plasticity, and to utilize Tregs for immunotherapy for T1D.
4. Islet antigen-reactive B cells and Antigen Presentation (Group leaders – John Cambier, University of Colorado SOM, Remi Creusot, Columbia University, Abdel Hamad Johns Hopkins, Sally Kent, University of Massachusetts SOM, Georgia Fousteri, Ospedale di San Raffaele)
The B cell team aims to elucidate the role of B cells in human T1D, including islet antigen reactivity repertoire, activation, loss of tolerance, and contribution in the stimulation of autoreactive effector T cells and Tfhs in T1D patients. The APC team is to identify dendritic and stromal cell subsets that play a role in inducing tolerance to beta cell antigens, and to determine whether these populations are functionally defective in T1D patients.
5. Cell/Reagent Bank (Group leader – John Kaddis, City of Hope)
The cell/reagent bank currently provides TCR information of islet-specific T cells identified in T1D patients as well as in NOD mice via the nPOD DataShare website. Future goals include providing reagents and cells generated from nPOD materials (e.g., tetramers, vectors, T cell avatars, and B cell lines transformed with Epstein-Barr virus, etc).