scholarly journals N-terminal additions to the WE14 peptide of chromogranin A create strong autoantigen agonists in type 1 diabetes

2015 ◽  
Vol 112 (43) ◽  
pp. 13318-13323 ◽  
Author(s):  
Niyun Jin ◽  
Yang Wang ◽  
Frances Crawford ◽  
Janice White ◽  
Philippa Marrack ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Lymph Nodes ◽  
Chromogranin A ◽  
Cell Clones ◽  
T Cell Stimulation ◽  
N Terminus ◽  
Pancreatic Lymph Nodes

Chromogranin A (ChgA) is an autoantigen for CD4+ T cells in the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D). The natural ChgA-processed peptide, WE14, is a weak agonist for the prototypical T cell, BDC-2.5, and other ChgA-specific T-cell clones. Mimotope peptides with much higher activity share a C-terminal motif, WXRM(D/E), that is predicted to lie in the p5 to p9 position in the mouse MHC class II, IAg7 binding groove. This motif is also present in WE14 (WSRMD), but at its N terminus. Therefore, to place the WE14 motif into the same position as seen in the mimotopes, we added the amino acids RLGL to its N terminus. Like the other mimotopes, RLGL-WE14, is much more potent than WE14 in T-cell stimulation and activates a diverse population of CD4+ T cells, which also respond to WE14 as well as islets from WT, but not ChgA−/− mice. The crystal structure of the IAg7–RLGL–WE14 complex confirmed the predicted placement of the peptide within the IAg7 groove. Fluorescent IAg7–RLGL–WE14 tetramers bind to ChgA-specific T-cell clones and easily detect ChgA-specific T cells in the pancreas and pancreatic lymph nodes of NOD mice. The prediction that many different N-terminal amino acid extensions to the WXRM(D/E) motif are sufficient to greatly improve T-cell stimulation leads us to propose that such a posttranslational modification may occur uniquely in the pancreas or pancreatic lymph nodes, perhaps via the mechanism of transpeptidation. This modification could account for the escape of these T cells from thymic negative selection.

scholarly journals Reduced Follicular Regulatory T Cells in Spleen and Pancreatic Lymph Nodes of Patients With Type 1 Diabetes

Diabetes ◽  
2021 ◽  
pp. db210091
Author(s):  
Andrea Vecchione ◽  
Tatiana Jofra ◽  
Jolanda Gerosa ◽  
Kimberly Shankwitz ◽  
Roberta Di Fonte ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Regulatory T Cells ◽  
Lymph Nodes ◽  
Pancreatic Lymph Nodes

scholarly journals Administration of Human Derived Upper gut Commensal Prevotella histicola delays the onset of type 1 diabetes in NOD mice

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Eric Marietta ◽  
Irina Horwath ◽  
Stephanie Meyer ◽  
Shahryar Khaleghi-Rostamkolaei ◽  
Eric Norman ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Regulatory T Cells ◽  
Lymph Nodes ◽  
Nod Mice ◽  
Histopathological Analysis ◽  
Microbial Composition ◽  
Time Points ◽  
Pancreatic Lymph Nodes

Abstract Background Type 1 diabetes (T1D) is an autoimmune disease that is increasing in prevalence worldwide. One of the contributing factors to the pathogenesis of T1D is the composition of the intestinal microbiota, as has been demonstrated. in T1D patients, with some studies demonstrating a deficiency in their levels of Prevotella. We have isolated a strain of Prevotella histicola from a duodenal biopsy that has anti-inflammatory properties, and in addition, alters the development of autoimmune diseases in mouse models. Therefore, our hypothesis is that the oral administration of P. histicola might delay the development of T1D in the non-obese diabetic (NOD) mice. To assess this, we used the following materials and methods. Female NOD mice (ages 5–8 weeks) were administered every other day P. histicola that was cultured in-house. Blood glucose levels were measured every other week. Mice were sacrificed at various time points for histopathological analysis of the pancreas. Modulation of immune response by the commensal was tested by analyzing regulatory T-cells and NKp46+ cells using flow cytometry and intestinal cytokine mRNA transcript levels using quantitative RT-PCR. For microbial composition, 16 s rRNA gene analysis was conducted on stool samples collected at various time points. Results Administration of P. histicola in NOD mice delayed the onset of T1D. Beta diversity in the fecal microbiomes demonstrated that the microbial composition of the mice administered P. histicola was different from those that were not treated. Treatment with P. histicola led to a significant increase in regulatory T cells with a concomitant decrease in NKp46+ cells in the pancreatic lymph nodes as compared to the untreated group after 5 weeks of treatment. Conclusions These observations suggest that P. histicola treatment delayed onset of diabetes by increasing the levels of regulatory T cells in the pancreatic lymph nodes. This preliminary work supports the rationale that enteral exposure to a non pathogenic commensal P. histicola be tested as a future therapy for T1D.

scholarly journals Optimization of a Method to Detect Autoantigen-Specific T-Cell Responses in Type 1 Diabetes

2020 ◽  
Vol 11 ◽  
Author(s):  
Yassmin Musthaffa ◽  
Hendrik J. Nel ◽  
Nishta Ramnoruth ◽  
Swati Patel ◽  
Emma E. Hamilton-Williams ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
T Cell Responses ◽  
Critical Issue ◽  
Critical Elements ◽  
Cell Responses ◽  
T Cell Stimulation ◽  
Promising Therapeutic Approach

The development of tolerizing therapies aiming to inactivate autoreactive effector T-cells is a promising therapeutic approach to control undesired autoimmune responses in human diseases such as Type 1 Diabetes (T1D). A critical issue is a lack of sensitive and reproducible methods to analyze antigen-specific T-cell responses, despite various attempts. We refined a proliferation assay using the fluorescent dye 5,6-carboxylfluorescein diacetate succinimidyl ester (CFSE) to detect responding T-cells, highlighting the fundamental issues to be taken into consideration to monitor antigen-specific responses in patients with T1D. The critical elements that maximize detection of antigen-specific responses in T1D are reduction of blood storage time, standardization of gating parameters, titration of CFSE concentration, selecting the optimal CFSE staining duration and the duration of T-cell stimulation, and freezing in medium containing human serum. Optimization of these elements enables robust, reproducible application to longitudinal cohort studies or clinical trial samples in which antigen-specific T-cell responses are relevant, and adaptation to other autoimmune diseases.

scholarly journals Abnormal Cannabidiol protects pancreatic beta cells in mouse models of experimental Type 1 diabetes

2020 ◽  
Author(s):  
Isabel Gonzalez-Mariscal ◽  
Macarena Pozo Morales ◽  
Silvana Yanina Romero-Zerbo ◽  
Vanesa Espinosa-Jimenez ◽  
Alejandro Escamilla ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Lymph Nodes ◽  
Beta Cell ◽  
Mouse Models ◽  
Nod Mice ◽  
List Type ◽  
Pancreatic Lymph Nodes ◽  
Islet Inflammation

ABSTRACTBackground and PurposeThe atypical cannabinoid Abn-CBD was reported to improve the inflammatory status in preclinical models of several pathologies including autoimmune diseases. However, its potential for autoimmune diabetes, i.e. type 1 diabetes (T1D), is unknown.Experimental ApproachWe used two mouse models of T1D, streptozotocin (STZ)-injected and non-obese diabetic (NOD) mice. Eight-to-ten-week-old male C57Bl6/J mice were pre-treated with Abn-CBD (1mg/kg of body weight) or vehicle for 1 week, following STZ treatment, and euthanized 1 week later. Six-week-old female NOD mice were treated with Abn-CBD (0.1-1mg/kg) or vehicle for 12 weeks and then euthanized. Blood, pancreas, pancreatic lymph nodes and circulating T cells were collected and processed for analysis. Glycemia was also monitored.Key ResultsAbn-CBD decreased circulating proinflammatory cytokines, ameliorated islet inflammation and the autoimmune attack, showing a 2-fold decrease in CD8+ T cells infiltration and reduced Th1/Th2 ratio in pancreatic lymph nodes of STZ-injected mice. Mechanistically, Abn-CBD reduced intra-islet phospho-NF-κB and TXNIP. Concomitant reduction of islet cell apoptosis and intra-islet fibrosis were observed in Abn-CBD pre-treated mice compared to vehicle. In NOD mice, Abn-CBD reduced the expression of Ifng, Il21, Tnfa and Il10 while increased Il4 in circulating CD4+ T cells compared to vehicle, reducing the severity of insulitis and improving glucose tolerance.Conclusion and ImplicationsAltogether, we found that Abn-CBD reduces intra-islet inflammation and delays the progression of insulitis in mouse models of T1D, preserving healthy functional islets. Hence, Abn-CBD and related compounds emerge as new candidates to develop pharmacological strategies to treat early stages of T1D.WHAT IS ALREADY KNOWN-Phytocannabinoids such as cannabidiol (CBD) have anti-inflammatory and glucose-lowering properties-The CBD derivative Abn-CBD ameliorates inflammation in various diseases and modulates beta cell functionWHAT THIS STUDY ADDS-Abn-CBD reduces systemic and pancreatic inflammation in mice models of type 1 diabetes-Abn-CBD prevents beta cell damage and loss during type 1 diabetes onsetCLINICAL SIGNIFICANCE-Synthetic cannabinoids emerge as potential treatment for type 1 diabetes

scholarly journals Proinsulin C-peptide is an autoantigen in people with type 1 diabetes

2018 ◽  
Vol 115 (42) ◽  
pp. 10732-10737 ◽  
Author(s):  
Michelle So ◽  
Colleen M. Elso ◽  
Eleonora Tresoldi ◽  
Miha Pakusch ◽  
Vimukthi Pathiraja ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Full Length ◽  
C Peptide ◽  
T Cell Clones ◽  
Recent Onset ◽  
Cell Clones ◽  
Hla Dq2

Type 1 diabetes (T1D) is an autoimmune disease in which insulin-producing beta cells, found within the islets of Langerhans in the pancreas, are destroyed by islet-infiltrating T cells. Identifying the antigenic targets of beta-cell reactive T cells is critical to gain insight into the pathogenesis of T1D and develop antigen-specific immunotherapies. Several lines of evidence indicate that insulin is an important target of T cells in T1D. Because many human islet-infiltrating CD4+ T cells recognize C-peptide–derived epitopes, we hypothesized that full-length C-peptide (PI33–63), the peptide excised from proinsulin as it is converted to insulin, is a target of CD4+ T cells in people with T1D. CD4+ T cell responses to full-length C-peptide were detected in the blood of: 14 of 23 (>60%) people with recent-onset T1D, 2 of 15 (>13%) people with long-standing T1D, and 1 of 13 (<8%) HLA-matched people without T1D. C-peptide–specific CD4+ T cell clones, isolated from six people with T1D, recognized epitopes from the entire 31 amino acids of C-peptide. Eighty-six percent (19 of 22) of the C-peptide–specific clones were restricted by HLA-DQ8, HLA-DQ2, HLA-DQ8trans, or HLA-DQ2trans, HLA alleles strongly associated with risk of T1D. We also found that full-length C-peptide was a much more potent agonist of some CD4+ T cell clones than an 18mer peptide encompassing the cognate epitope. Collectively, our findings indicate that proinsulin C-peptide is a key target of autoreactive CD4+ T cells in T1D. Hence, full-length C-peptide is a promising candidate for antigen-specific immunotherapy in T1D.

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.

scholarly journals Increased islet antigen–specific regulatory and effector CD4+ T cells in healthy individuals with the type 1 diabetes–protective haplotype

2020 ◽  
Vol 5 (44) ◽  
pp. eaax8767 ◽  
Author(s):  
Xiaomin Wen ◽  
Junbao Yang ◽  
Eddie James ◽  
I-Ting Chow ◽  
Helena Reijonen ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Regulatory T Cells ◽  
Interleukin 4 ◽  
Specific Class ◽  
Protective Haplotype ◽  
Specific Effector ◽  
Islet Antigen

The DRB1*15:01-DQB1*06:02 (DR1501-DQ6) haplotype is linked to dominant protection from type 1 diabetes, but the cellular mechanism for this association is unclear. To address this question, we identified multiple DR1501- and DQ6-restricted glutamate decarboxylase 65 (GAD65) and islet-specific glucose-6-phosphatase catalytic subunit–related protein (IGRP)–specific T cell epitopes. Three of the DR1501/DQ6-restricted epitopes identified were previously reported to be restricted by DRB1*04:01/DRB1*03:01/DQB1*03:02. We also used specific class II tetramer reagents to assess T cell frequencies. Our results indicated that GAD65- and IGRP-specific effector and CD25+CD127−FOXP3+ regulatory CD4+ T cells were present at higher frequencies in individuals with the protective haplotype than those with susceptible or neutral haplotypes. We further confirmed higher frequencies of islet antigen–specific effector and regulatory CD4+ T cells in DR1501-DQ6 individuals through a CD154/CD137 up-regulation assay. DR1501-restricted effector T cells were capable of producing interferon-γ (IFN-γ) and interleukin-4 (IL-4) but were more likely to produce IL-10 compared with effectors from individuals with susceptible haplotypes. To evaluate their capacity for antigen-specific regulatory activity, we cloned GAD65 and IGRP epitope–specific regulatory T cells. We showed that these regulatory T cells suppressed DR1501-restricted GAD65- and IGRP-specific effectors and DQB1*03:02-restricted GAD65-specific effectors in an antigen-specific fashion. In total, these results suggest that the protective DR1501-DQ6 haplotype confers protection through increased frequencies of islet-specific IL-10–producing T effectors and CD25+CD127−FOXP3+ regulatory T cells.

scholarly journals Self-reactive human CD4 T cell clones form unusual immunological synapses

2012 ◽  
Vol 209 (2) ◽  
pp. 335-352 ◽  
Author(s):  
David A. Schubert ◽  
Susana Gordo ◽  
Joseph J. Sabatino ◽  
Santosh Vardhana ◽  
Etienne Gagnon ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
T Cell Clones ◽  
Cell Clones ◽  
Immunological Synapses ◽  
High Degree ◽  
Self Antigen

Recognition of self–peptide-MHC (pMHC) complexes by CD4 T cells plays an important role in the pathogenesis of many autoimmune diseases. We analyzed formation of immunological synapses (IS) in self-reactive T cell clones from patients with multiple sclerosis and type 1 diabetes. All self-reactive T cells contained a large number of phosphorylated T cell receptor (TCR) microclusters, indicative of active TCR signaling. However, they showed little or no visible pMHC accumulation or transport of TCR–pMHC complexes into a central supramolecular activation cluster (cSMAC). In contrast, influenza-specific T cells accumulated large quantities of pMHC complexes in microclusters and a cSMAC, even when presented with 100-fold lower pMHC densities. The self-reactive T cells also maintained a high degree of motility, again in sharp contrast to virus-specific T cells. 2D affinity measurements of three of these self-reactive T cell clones demonstrated a normal off-rate but a slow on-rate of TCR binding to pMHC. These unusual IS features may facilitate escape from negative selection by self-reactive T cells encountering very small amounts of self-antigen in the thymus. However, these same features may enable acquisition of effector functions by self-reactive T cells encountering large amounts of self-antigen in the target organ of the autoimmune disease.

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