scholarly journals How C-terminal additions to insulin B-chain fragments create superagonists for T cells in mouse and human type 1 diabetes

2019 ◽  
Vol 4 (34) ◽  
pp. eaav7517 ◽  
Author(s):  
Yang Wang ◽  
Tomasz Sosinowski ◽  
Andrey Novikov ◽  
Frances Crawford ◽  
Janice White ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cell Receptor ◽  
Proper Position ◽  
Peptide Epitopes ◽  
Human Type 1 Diabetes

In type 1 diabetes (T1D), proinsulin is a major autoantigen and the insulin B:9-23 peptide contains epitopes for CD4+ T cells in both mice and humans. This peptide requires carboxyl-terminal mutations for uniform binding in the proper position within the mouse IAg7 or human DQ8 major histocompatibility complex (MHC) class II (MHCII) peptide grooves and for strong CD4+ T cell stimulation. Here, we present crystal structures showing how these mutations control CD4+ T cell receptor (TCR) binding to these MHCII-peptide complexes. Our data reveal stricking similarities between mouse and human CD4+ TCRs in their interactions with these ligands. We also show how fusions between fragments of B:9-23 and of proinsulin C-peptide create chimeric peptides with activities as strong or stronger than the mutated insulin peptides. We propose transpeptidation in the lysosome as a mechanism that could accomplish these fusions in vivo, similar to the creation of fused peptide epitopes for MHCI presentation shown to occur by transpeptidation in the proteasome. Were this mechanism limited to the pancreas and absent in the thymus, it could provide an explanation for how diabetogenic T cells escape negative selection during development but find their modified target antigens in the pancreas to cause T1D.

scholarly journals In Vivo Selection of T-Cell Receptor Junctional Region Sequences by HLA-A2 Human T-Cell Lymphotropic Virus Type 1 Tax11-19 Peptide Complexes

2001 ◽  
Vol 75 (2) ◽  
pp. 1065-1071 ◽  
Author(s):  
Mineki Saito ◽  
Graham P. Taylor ◽  
Akiko Saito ◽  
Yoshitaka Furukawa ◽  
Koichiro Usuku ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Virus Type ◽  
Cell Receptor ◽  
Antigen Specificity ◽  
Human T Cell ◽  
Cdr3 Region

ABSTRACT Using HLA-peptide tetrameric complexes, we isolated human T-cell lymphotrophic virus type 1 Tax peptide-specific CD8+ T cells ex vivo. Antigen-specific amino acid motifs were identified in the T-cell receptor Vβ CDR3 region of clonally expanded CD8+ T cells. This result directly confirms the importance of the CDR3 region in determining the antigen specificity in vivo.

scholarly journals Proinsulin-Reactive CD4 T Cells in the Islets of Type 1 Diabetes Organ Donors

2021 ◽  
Vol 12 ◽  
Author(s):  
Laurie G. Landry ◽  
Amanda M. Anderson ◽  
Holger A. Russ ◽  
Liping Yu ◽  
Sally C. Kent ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Cd4 T Cells ◽  
Pancreatic Beta Cells ◽  
Hot Spot ◽  
Cell Receptor ◽  
Organ Donors ◽  
Hla Dq

Proinsulin is an abundant protein that is selectively expressed by pancreatic beta cells and has been a focus for development of antigen-specific immunotherapies for type 1 diabetes (T1D). In this study, we sought to comprehensively evaluate reactivity to preproinsulin by CD4 T cells originally isolated from pancreatic islets of organ donors having T1D. We analyzed 187 T cell receptor (TCR) clonotypes expressed by CD4 T cells obtained from six T1D donors and determined their response to 99 truncated preproinsulin peptide pools, in the presence of autologous B cells. We identified 14 TCR clonotypes from four out of the six donors that responded to preproinsulin peptides. Epitopes were found across all of proinsulin (insulin B-chain, C-peptide, and A-chain) including four hot spot regions containing peptides commonly targeted by TCR clonotypes derived from multiple T1D donors. Of importance, these hot spots overlap with peptide regions to which CD4 T cell responses have previously been detected in the peripheral blood of T1D patients. The 14 TCR clonotypes recognized proinsulin peptides presented by various HLA class II molecules, but there was a trend for dominant restriction with HLA-DQ, especially T1D risk alleles DQ8, DQ2, and DQ8-trans. The characteristics of the tri-molecular complex including proinsulin peptide, HLA-DQ molecule, and TCR derived from CD4 T cells in islets, provides an essential basis for developing antigen-specific biomarkers as well as immunotherapies.

Cytokine-induced IL-10–secreting CD8 T cells represent a phenotypically distinct suppressor T-cell lineage

Blood ◽  
2006 ◽  
Vol 107 (11) ◽  
pp. 4475-4483 ◽  
Author(s):  
Alistair Noble ◽  
Angela Giorgini ◽  
Jamie A. Leggat
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cell Lineage ◽  
Cd8 T Cell ◽  
Cell Receptor ◽  
Cell Interaction ◽  
Cell Contact ◽  
Cell Based Therapy

Abstract Populations of regulatory T cells (Tregs) control autoimmune and allergic immunopathology induced by self or foreign antigens. Several types of CD4+ MHC class II–restricted Treg populations have been characterized, but the biology of CD8+, MHC class I–restricted Tregs is less understood. We show here that CD8+ Tregs are rapidly generated in the presence of IL-4 and IL-12, produce IL-10, and exhibit a unique cell-surface phenotype with coexpression of activation and naive cell-associated markers. They block activation of naive or effector T cells and suppress IgG/IgE antibody responses and graft-versus-host disease in vivo. Suppression is dependent on cell contact and mediated by direct T-cell–T-cell interaction that antagonizes T-cell–receptor (TCR) signals. The data establish the existence of a CD8 T-cell suppressor effector subset distinct in both phenotype and function from T cytotoxic 1 (Tc1) and Tc2 cells. Production of such CD8 Tregs has potential for cell-based therapy of CD4 or CD8 T-cell–mediated disease.

scholarly journals Targeting transcriptional coregulator OCA-B/Pou2af1 blocks activated autoreactive T cells in the pancreas and type-1 diabetes

2020 ◽  
Author(s):  
Heejoo Kim ◽  
Jelena Perovanovic ◽  
Arvind Shakya ◽  
Zuolian Shen ◽  
Cody N. German ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Target Genes ◽  
Autoimmune Diabetes ◽  
Nod Mice ◽  
Cell Receptor ◽  
Glucose Levels ◽  
Transcriptional Coregulator

AbstractThe transcriptional coregulator OCA-B promotes expression of T cell target genes in cases of repeated antigen exposure, a necessary feature of autoimmunity. We hypothesized that T cell-specific OCA-B deletion and pharmacologic OCA-B inhibition would protect mice from autoimmune diabetes. We developed an Ocab conditional allele and backcrossed it onto a diabetes-prone NOD/ShiLtJ strain background. T cell-specific OCA-B loss protected mice from spontaneous disease. Protection was associated with large reductions in islet CD8+ T cell receptor specificities associated with diabetes pathogenesis. CD4+ clones associated with diabetes were present, but associated with anergic phenotypes. The protective effect of OCA-B loss was recapitulated using autoantigen-specific NY8.3 mice, but diminished in monoclonal models specific to artificial or neoantigens. Rationally-designed membrane-penetrating OCA-B peptide inhibitors normalized glucose levels, and reduced T cell infiltration and proinflammatory cytokine expression in newly-diabetic NOD mice. Together, the results indicate that OCA-B is a potent autoimmune regulator and a promising target for pharmacologic inhibition.~40-word summary statement for the online JEM table of contents and alertsKim and colleagues show that OCA-B in T cells is essential for the generation of type-1 diabetes. OCA-B loss leaves the pancreatic lymph nodes largely undisturbed, but associates autoreactive CD4+ T cells in the pancreas with anergy while deleting potentially autoreactive CD8+ T cells.SummaryKim et al. show that loss or inhibition of OCA-B in T cells protects mice from type-1 diabetes.

scholarly journals Identifying New Hybrid Insulin Peptides (HIPs) in Type 1 Diabetes

2021 ◽  
Vol 12 ◽  
Author(s):  
Stuart I. Mannering ◽  
Alan F. Rubin ◽  
Ruike Wang ◽  
Pushpak Bhattacharjee
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Current Data ◽  
Detailed Knowledge ◽  
Peptide Fragments ◽  
Immune Pathogenesis ◽  
New Type ◽  
Human Type 1 Diabetes

In 2016 Delong et al. discovered a new type of neoepitope formed by the fusion of two unrelated peptide fragments. Remarkably these neoepitopes, called hybrid insulin peptides, or HIPs, are recognized by pathogenic CD4+ T cells in the NOD mouse and human pancreatic islet-infiltrating T cells in people with type 1 diabetes. Current data implicates CD4+ T-cell responses to HIPs in the immune pathogenesis of human T1D. Because of their role in the immune pathogenesis of human T1D it is important to identify new HIPs that are recognized by CD4+ T cells in people at risk of, or with, T1D. A detailed knowledge of T1D-associated HIPs will allow HIPs to be used in assays to monitor changes in T cell mediated beta-cell autoimmunity. They will also provide new targets for antigen-specific therapies for T1D. However, because HIPs are formed by the fusion of two unrelated peptides there are an enormous number of potential HIPs which makes it technically challenging to identify them. Here we review the discovery of HIPs, how they form and discuss approaches to identifying new HIPs relevant to the immune pathogenesis of human type 1 diabetes.

scholarly journals Using the T Cell Receptor as a Biomarker in Type 1 Diabetes

2021 ◽  
Vol 12 ◽  
Author(s):  
Maki Nakayama ◽  
Aaron W. Michels
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Current Knowledge ◽  
Autoimmune Diabetes ◽  
Cell Activity ◽  
Cell Receptor ◽  
Antigen Specificity ◽  
Unique Markers

T cell receptors (TCRs) are unique markers that define antigen specificity for a given T cell. With the evolution of sequencing and computational analysis technologies, TCRs are now prime candidates for the development of next-generation non-cell based T cell biomarkers, which provide a surrogate measure to assess the presence of antigen-specific T cells. Type 1 diabetes (T1D), the immune-mediated form of diabetes, is a prototypical organ specific autoimmune disease in which T cells play a pivotal role in targeting pancreatic insulin-producing beta cells. While the disease is now predictable by measuring autoantibodies in the peripheral blood directed to beta cell proteins, there is an urgent need to develop T cell markers that recapitulate T cell activity in the pancreas and can be a measure of disease activity. This review focuses on the potential and challenges of developing TCR biomarkers for T1D. We summarize current knowledge about TCR repertoires and clonotypes specific for T1D and discuss challenges that are unique for autoimmune diabetes. Ultimately, the integration of large TCR datasets produced from individuals with and without T1D along with computational ‘big data’ analysis will facilitate the development of TCRs as potentially powerful biomarkers in the development of T1D.

scholarly journals Identification of Candidate Tolerogenic CD8+T Cell Epitopes for Therapy of Type 1 Diabetes in the NOD Mouse Model

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Cailin Yu ◽  
Jeremy C. Burns ◽  
William H. Robinson ◽  
Paul J. Utz ◽  
Peggy P. Ho ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Nod Mice ◽  
Cell Protein ◽  
T Cell Epitopes ◽  
Predictive Algorithms ◽  
Murine Homolog ◽  
Human Type 1 Diabetes

Type 1 diabetes is an autoimmune disease in which insulin-producing pancreatic isletβcells are the target of self-reactive B and T cells. T cells reactive with epitopes derived from insulin and/or IGRP are critical for the initiation and maintenance of disease, but T cells reactive with other islet antigens likely have an essential role in disease progression. We sought to identify candidate CD8+T cell epitopes that are pathogenic in type 1 diabetes. Proteins that elicit autoantibodies in human type 1 diabetes were analyzed by predictive algorithms for candidate epitopes. Using several different tolerizing regimes using synthetic peptides, two new predicted tolerogenic CD8+T cell epitopes were identified in the murine homolog of the major human islet autoantigen zinc transporter ZnT8 (aa 158–166 and 282–290) and one in a non-βcell protein, dopamineβ-hydroxylase (aa 233–241). Tolerizing vaccination of NOD mice with a cDNA plasmid expressing full-length proinsulin prevented diabetes, whereas plasmids encoding ZnT8 and DβH did not. However, tolerizing vaccination of NOD mice with the proinsulin plasmid in combination with plasmids expressing ZnT8 and DβH decreased insulitis and enhanced prevention of disease compared to vaccination with the plasmid encoding proinsulin alone.

scholarly journals Differentiating MHC-dependent and -independent mechanisms of lymph node stromal cell regulation of proinsulin-specific CD8+ T-cells in type 1 diabetes

2020 ◽  
Author(s):  
Ada Admin ◽  
Terri C. Thayer ◽  
Joanne Davies ◽  
James A. Pearson ◽  
Stephanie J. Hanna ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Lymph Node ◽  
T Cell ◽  
Cell Receptor ◽  
Peripheral Tolerance ◽  
Beta Cell Destruction ◽  
Nonobese Diabetic ◽  
Autoreactive Cells

Lymph node stromal cells (LNSC) are essential for providing and maintaining peripheral self-tolerance of potentially autoreactive cells. In type 1 diabetes, proinsulin-specific CD8<sup>+</sup>T-cells, escaping central and peripheral tolerance, contribute to beta-cell destruction. Using G9Cα<sup>-/-</sup>CD8<sup>+</sup>T-cells specific for proinsulin, we studied the mechanisms by which LNSC regulate low-avidity autoreactive cells in the nonobese diabetic (NOD) mouse model of type 1 diabetes. Whereas MHC-matched NOD-LNSC significantly reduced G9Cα<sup>-/-</sup>CD8<sup>+</sup>T-cell cytotoxicity and DC-induced proliferation, they failed to sufficiently regulate T-cells stimulated by anti-CD3/CD28. In contrast, non-MHC matched, control C57BL/6 mouse LNSC suppressed T-cell receptor engagement by anti-CD3/CD28 via MHC-independent mechanisms. This C57BL/6-LNSC suppression was maintained even after removal of the LNSC, demonstrating a direct effect of LNSC on T-cells, modifying antigen sensitivity and effector function. Thus, our results suggest that a loss of NOD-LNSC MHC-independent suppressive mechanisms may contribute to diabetes development.

scholarly journals NKG2D signaling within the pancreatic islets reduces NOD diabetes and increases protective central memory CD8+ T cell numbers

2020 ◽  
Author(s):  
Ada Admin ◽  
Andrew P. Trembath ◽  
Kelsey L. Krausz ◽  
Neekun Sharma ◽  
Ivan C. Gerling ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Autoimmune Diabetes ◽  
Central Memory ◽  
Anatomical Location

NKG2D is implicated in autoimmune diabetes. However, the role of this receptor in diabetes pathogenesis is unclear owing to conflicting results with studies involving global inhibition of NKG2D signaling. We found that NKG2D and its ligands are present in human pancreata, with expression of NKG2D and its ligands increased in the islets of patients with type 1 diabetes. To directly assess the role of NKG2D in the pancreas, we generated NOD mice that express an NKG2D ligand in b-islet cells. Diabetes was reduced in these mice. The reduction corresponded with a decrease in the effector to central memory CD8<sup>+</sup> T cell ratio. Further, NKG2D signaling during in vitro activation of both mouse and human CD8+ T cells resulted in an increased number of central memory CD8<sup>+</sup> T cells and diabetes protection by central memory CD8<sup>+</sup> T cells in vivo. Taken together, these studies demonstrate that there is a protective role for central memory CD8<sup>+</sup> T cells in autoimmune diabetes and that this protection is enhanced with NKG2D signaling. These findings stress the importance of anatomical location when determining the role NKG2D signaling plays, as well as when developing therapeutic strategies targeting this pathway, in type 1 diabetes development.

scholarly journals A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune type 1 diabetes

2018 ◽  
Vol 10 (422) ◽  
pp. eaag1782 ◽  
Author(s):  
Isabelle Serr ◽  
Martin G. Scherm ◽  
Adam M. Zahm ◽  
Jonathan Schug ◽  
Victoria K. Flynn ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Early Stage ◽  
Tolerance Induction ◽  
Islet Autoimmunity ◽  
Activated T Cells

Molecular checkpoints that trigger the onset of islet autoimmunity or progression to human type 1 diabetes (T1D) are incompletely understood. Using T cells from children at an early stage of islet autoimmunity without clinical T1D, we find that a microRNA181a (miRNA181a)–mediated increase in signal strength of stimulation and costimulation links nuclear factor of activated T cells 5 (NFAT5) with impaired tolerance induction and autoimmune activation. We show that enhancing miRNA181a activity increases NFAT5 expression while inhibiting FOXP3+ regulatory T cell (Treg) induction in vitro. Accordingly, Treg induction is improved using T cells from NFAT5 knockout (NFAT5ko) animals, whereas altering miRNA181a activity does not affect Treg induction in NFAT5ko T cells. Moreover, high costimulatory signals result in phosphoinositide 3-kinase (PI3K)–mediated NFAT5, which interferes with FoxP3+ Treg induction. Blocking miRNA181a or NFAT5 increases Treg induction in murine and humanized models and reduces murine islet autoimmunity in vivo. These findings suggest targeting miRNA181a and/or NFAT5 signaling for the development of innovative personalized medicines to limit islet autoimmunity.

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