Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
1.
J Immunol ; 203(1): 48-57, 2019 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-31109955

RESUMEN

CD4 T cells play a critical role in promoting the development of autoimmunity in type 1 diabetes. The diabetogenic CD4 T cell clone BDC-2.5, originally isolated from a NOD mouse, has been widely used to study the contribution of autoreactive CD4 T cells and relevant Ags to autoimmune diabetes. Recent work from our laboratory has shown that the Ag for BDC-2.5 T cells is a hybrid insulin peptide (2.5HIP) consisting of an insulin C-peptide fragment fused to a peptide from chromogranin A (ChgA) and that endogenous 2.5HIP-reactive T cells are major contributors to autoimmune pathology in NOD mice. The objective of this study was to determine if poly(lactide-co-glycolide) (PLG) nanoparticles (NPs) loaded with the 2.5HIP Ag (2.5HIP-coupled PLG NPs) can tolerize BDC-2.5 T cells. Infusion of 2.5HIP-coupled PLG NPs was found to prevent diabetes in an adoptive transfer model by impairing the ability of BDC-2.5 T cells to produce proinflammatory cytokines through induction of anergy, leading to an increase in the ratio of Foxp3+ regulatory T cells to IFN-γ+ effector T cells. To our knowledge, this work is the first to use a hybrid insulin peptide, or any neoepitope, to re-educate diabetogenic T cells and may have significant implications for the development of an Ag-specific therapy for type 1 diabetes patients.


Asunto(s)
Cromogranina A/metabolismo , Diabetes Mellitus Tipo 1/terapia , Inmunoterapia/métodos , Insulina/metabolismo , Nanopartículas/uso terapéutico , Péptidos/metabolismo , Proteínas Recombinantes de Fusión/uso terapéutico , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T Reguladores/inmunología , Animales , Animales Modificados Genéticamente , Células Cultivadas , Cromogranina A/genética , Diabetes Mellitus Tipo 1/inmunología , Modelos Animales de Enfermedad , Factores de Transcripción Forkhead/metabolismo , Humanos , Tolerancia Inmunológica , Insulina/genética , Interferón gamma/metabolismo , Ratones , Ratones Endogámicos NOD , Nanopartículas/metabolismo , Péptidos/genética , Receptores de Antígenos de Linfocitos T/genética , Proteínas Recombinantes de Fusión/genética
2.
J Immunol ; 196(1): 39-43, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26608914

RESUMEN

T cells reactive to ß cell Ags are critical players in the development of autoimmune type 1 diabetes. Using a panel of diabetogenic CD4 T cell clones derived from the NOD mouse, we recently identified the ß cell secretory granule protein, chromogranin A (ChgA), as a new autoantigen in type 1 diabetes. CD4 T cells reactive to ChgA are pathogenic and rapidly transfer diabetes into young NOD recipients. We report in this article that NOD.ChgA(-/-) mice do not develop diabetes and show little evidence of autoimmunity in the pancreatic islets. Using tetramer analysis, we demonstrate that ChgA-reactive T cells are present in these mice but remain naive. In contrast, in NOD.ChgA(+/+) mice, a majority of the ChgA-reactive T cells are Ag experienced. Our results suggest that the presence of ChgA and subsequent activation of ChgA-reactive T cells are essential for the initiation and development of autoimmune diabetes in NOD mice.


Asunto(s)
Autoantígenos/inmunología , Linfocitos T CD4-Positivos/inmunología , Cromogranina A/genética , Diabetes Mellitus Tipo 1/genética , Traslado Adoptivo , Animales , Autoinmunidad/inmunología , Linfocitos B/inmunología , Linfocitos T CD4-Positivos/trasplante , Linfocitos T CD8-positivos/inmunología , Células Cultivadas , Cromogranina A/inmunología , Diabetes Mellitus Tipo 1/inmunología , Citometría de Flujo , Islotes Pancreáticos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones Noqueados , Repeticiones de Microsatélite/genética
3.
J Autoimmun ; 78: 11-18, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-27802879

RESUMEN

BDC-6.9, a diabetogenic CD4 T cell clone isolated from a non-obese diabetic (NOD) mouse, responds to pancreatic islet cells from NOD but not BALB/c mice. We recently reported that a hybrid insulin peptide (HIP), 6.9HIP, formed by linkage of an insulin C-peptide fragment and a fragment of islet amyloid polypeptide (IAPP), is the antigen for BDC-6.9. We report here that the core 12-mer peptide from 6.9HIP, centered on the hybrid peptide junction, is also highly antigenic for BDC-6.9. In agreement with the observation that BALB/c islet cells fail to stimulate the T cell clone, a single amino acid difference in the BALB/c IAPP sequence renders the BALB/c version of the HIP only weakly antigenic. Mutant peptide analysis indicates that each parent molecule-insulin C-peptide and IAPP-donates residues critical for antigenicity. Through mass spectrometric analysis, we determine the distribution of naturally occurring 6.9HIP across chromatographic fractions of proteins from pancreatic beta cells. This distribution closely matches the profile of the T cell response to the fractions, confirming that 6.9HIP is the endogenous islet antigen for the clone. Using a new MHC II tetramer reagent, 6.9HIP-tet, we show that T cells specific for the 6.9HIP peptide are prevalent in the pancreas of diabetic NOD mice. Further study of HIPs and HIP-reactive T cells could yield valuable insight into key factors driving progression to diabetes and thereby inform efforts to prevent or reverse this disease.


Asunto(s)
Autoantígenos/inmunología , Linfocitos T CD4-Positivos/inmunología , Epítopos de Linfocito T/inmunología , Insulina/inmunología , Polipéptido Amiloide de los Islotes Pancreáticos/inmunología , Secuencia de Aminoácidos , Animales , Autoantígenos/química , Péptido C/química , Péptido C/inmunología , Linfocitos T CD4-Positivos/metabolismo , Células Cultivadas , Epítopos de Linfocito T/química , Insulina/química , Polipéptido Amiloide de los Islotes Pancreáticos/química , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Ratones Noqueados
4.
J Immunol ; 191(8): 3990-4, 2013 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-24043895

RESUMEN

We previously reported a peptide KS20 from islet amyloid polypeptide (IAPP) to be the target Ag for a highly diabetogenic CD4 T cell clone BDC-5.2.9. To track IAPP-reactive T cells in NOD mice and determine how they contribute to the pathogenesis of type 1 diabetes, we designed a new I-Ag7 tetramer with high affinity for BDC-5.2.9 that contains the peptide KS20. We found that significant numbers of KS20 tetramer(+) CD4 T cells can be detected in the pancreas of prediabetic and diabetic NOD mice. To verify pathogenicity of IAPP-reactive cells, we sorted KS20 tetramer(+) cells and cloned them from uncloned T cell lines isolated from spleen and lymph nodes of diabetic mice. We isolated a new KS20-reactive Th1 CD4 T cell clone that rapidly transfers diabetes. Our results suggest that IAPP triggers a broad autoimmune response by CD4 T cells in NOD mice.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Diabetes Mellitus Experimental/inmunología , Diabetes Mellitus Tipo 1/inmunología , Polipéptido Amiloide de los Islotes Pancreáticos/inmunología , Estado Prediabético/inmunología , Traslado Adoptivo , Animales , Autoantígenos/inmunología , Autoinmunidad/inmunología , Células Cultivadas , Antígenos de Histocompatibilidad Clase II/inmunología , Ganglios Linfáticos/citología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Páncreas/inmunología , Bazo/citología
5.
J Autoimmun ; 50: 38-41, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24239002

RESUMEN

Chromogranin A (ChgA) is a beta cell secretory granule protein and a peptide of ChgA, WE14, was recently identified as a ligand for diabetogenic CD4 T cell clones derived from the NOD mouse. In this study we compared responses of human CD4 T cells from recent onset type 1 diabetic (T1D) and control subjects to WE14 and to an enzymatically modified version of this peptide. T cell responders to antigens were detected in PBMCs from study subjects by an indirect CD4 ELISPOT assay for IFN-γ. T1D patients (n = 27) were recent onset patients within one year of diagnosis, typed for HLA-DQ8. Controls (n = 31) were either 1st degree relatives with no antibodies or from the HLA-matched general population cohort of DAISY/TEDDY. A second cohort of patients (n = 11) and control subjects (n = 11) was tested at lower peptide concentrations. We found that WE14 is recognized by T cells from diabetic subjects vs. controls in a dose dependent manner. Treatment of WE14 with transglutaminase increased reactivity to the peptide in some patients. This work suggests that ChgA is an important target antigen in human T1D subjects and that post-translational modification may play a role in its reactivity and relationship to disease.


Asunto(s)
Antígenos CD4/inmunología , Cromogranina A/inmunología , Diabetes Mellitus Tipo 1/genética , Péptidos/inmunología , Adolescente , Adulto , Autoantígenos/genética , Autoantígenos/inmunología , Antígenos CD4/genética , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Niño , Cromogranina A/genética , Cromogranina A/farmacología , Diabetes Mellitus Tipo 1/inmunología , Femenino , Expresión Génica , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/inmunología , Prueba de Histocompatibilidad , Humanos , Masculino , Péptidos/genética , Péptidos/farmacología , Cultivo Primario de Células , Transglutaminasas/metabolismo , Transglutaminasas/farmacología
6.
Diabetes ; 73(5): 743-750, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38295386

RESUMEN

Hybrid insulin peptides (HIPs) formed through covalent cross-linking of proinsulin fragments to secretory granule peptides are detectable within murine and human islets. The 2.5HIP (C-peptide-chromogranin A [CgA] HIP), recognized by the diabetogenic BDC-2.5 clone, is a major autoantigen in the nonobese diabetic mouse. However, the relevance of this epitope in human disease is currently unclear. A recent study probed T-cell reactivity toward HIPs in patients with type 1 diabetes, documenting responses in one-third of the patients and isolating several HIP-reactive T-cell clones. In this study, we isolated a novel T-cell clone and showed that it responds vigorously to the human equivalent of the 2.5HIP (designated HIP9). Although the responding patient carried the risk-associated DRB1*04:01/DQ8 haplotype, the response was restricted by DRB1*11:03 (DR11). HLA class II tetramer staining revealed higher frequencies of HIP9-reactive T cells in individuals with diabetes than in control participants. Furthermore, in DR11+ participants carrying the DRB4 allele, HIP9-reactive T-cell frequencies were higher than observed frequencies for the immunodominant proinsulin 9-28 epitope. Finally, there was a negative correlation between HIP9-reactive T-cell frequency and age at diagnosis. These results provide direct evidence that this C-peptide-CgA HIP is relevant in human type 1 diabetes and suggest a mechanism by which nonrisk HLA haplotypes may contribute to the development of ß-cell autoimmunity.


Asunto(s)
Diabetes Mellitus Tipo 1 , Insulina , Humanos , Animales , Ratones , Linfocitos T , Proinsulina , Péptido C , Cromogranina A , Péptidos , Insulina Regular Humana , Epítopos , Fragmentos de Péptidos
7.
Eur J Immunol ; 42(3): 672-80, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22488364

RESUMEN

We have investigated the role of CD40 signaling in islet-reactive, diabetogenic CD4(+) Th1 T-cell clones. Using multispectral flow cytometry, we showed that CD40 and CD154 are co-expressed and form complexes on the surface of activated T cells. We also demonstrate that activated Tcells can transactivate CD4(+) CD40(+) T cells through the CD40-CD154 pathway. To investigate the role of CD40 signaling on Th1 cells, we used the diabetogenic clone BDC-5.2.9 retrovirally transduced with a truncated form of the CD40 molecule to produce a CD40 dominant-negative T-cell clone. Upon challenge with antigen in vitro, the production of IFN-γ by BDC-5.2.9 CD40DN was greatly reduced and, in vivo, the dominant-negative variant was unable to induce diabetes. Transduction with the CD40DN vector was also effective in preventing transfer of disease by primary NOD CD4(+) T cells. Ex vivo analysis of pancreatic infiltrates after transfer of BDC-5.2.9 CD40DN cells revealed an overall reduction of cell numbers and cytokine production by both T cells and macrophages. These data indicate that CD40 is an important signaling molecule on autoreactive CD4(+) T cells and contributes to their pathogenic effector function.


Asunto(s)
Autoinmunidad/inmunología , Antígenos CD40/inmunología , Ligando de CD40/inmunología , Diabetes Mellitus Tipo 2/inmunología , Traslado Adoptivo/métodos , Animales , Linfocitos T CD4-Positivos/inmunología , Células Clonales , Citometría de Flujo , Activación de Linfocitos , Ratones , Ratones Endogámicos NOD , Ratones SCID , Microscopía Fluorescente , Transducción de Señal , Organismos Libres de Patógenos Específicos , Transducción Genética
8.
Front Immunol ; 13: 926650, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36032090

RESUMEN

Insulin is considered to be a key antigenic target of T cells in Type 1 Diabetes (T1D) and autoimmune diabetes in the NOD mouse with particular focus on the B-chain amino acid sequence B:9-23 as the primary epitope. Our lab previously discovered that hybrid insulin peptides (HIPs), comprised of insulin C-peptide fragments fused to other ß-cell granule peptides, are ligands for several pathogenic CD4 T cell clones derived from NOD mice and for autoreactive CD4 T cells from T1D patients. A subset of CD4 T cell clones from our panel react to insulin and B:9-23 but only at high concentrations of antigen. We hypothesized that HIPs might also be formed from insulin B-chain sequences covalently bound to other endogenously cleaved ß-cell proteins. We report here on the identification of a B-chain HIP, termed the 6.3HIP, containing a fragment of B:9-23 joined to an endogenously processed peptide of ProSAAS, as a strong neo-epitope for the insulin-reactive CD4 T cell clone BDC-6.3. Using an I-Ag7 tetramer loaded with the 6.3HIP, we demonstrate that T cells reactive to this B-chain HIP can be readily detected in NOD mouse islet infiltrates. This work suggests that some portion of autoreactive T cells stimulated by insulin B:9-23 may be responding to B-chain HIPs as peptide ligands.


Asunto(s)
Diabetes Mellitus Tipo 1 , Animales , Linfocitos T CD4-Positivos , Epítopos , Ratones , Ratones Endogámicos NOD , Fragmentos de Péptidos , Péptidos
9.
Diabetes ; 71(3): 483-496, 2022 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-35007324

RESUMEN

The induction of antigen (Ag)-specific tolerance and replacement of islet ß-cells are major ongoing goals for the treatment of type 1 diabetes (T1D). Our group previously showed that a hybrid insulin peptide (2.5HIP) is a critical autoantigen for diabetogenic CD4+ T cells in the NOD mouse model. In this study, we investigated whether induction of Ag-specific tolerance using 2.5HIP-coupled tolerogenic nanoparticles (NPs) could protect diabetic NOD mice from disease recurrence upon syngeneic islet transplantation. Islet graft survival was significantly prolonged in mice treated with 2.5HIP NPs, but not NPs containing the insulin B chain peptide 9-23. Protection in 2.5HIP NP-treated mice was attributed both to the simultaneous induction of anergy in 2.5HIP-specific effector T cells and the expansion of Foxp3+ regulatory T cells specific for the same Ag. Notably, our results indicate that effector function of graft-infiltrating CD4+ and CD8+ T cells specific for other ß-cell epitopes was significantly impaired, suggesting a novel mechanism of therapeutically induced linked suppression. This work establishes that tolerance induction with an HIP can delay recurrent autoimmunity in NOD mice, which could inform the development of an Ag-specific therapy for T1D.


Asunto(s)
Diabetes Mellitus Tipo 1/terapia , Supervivencia de Injerto/efectos de los fármacos , Insulina/administración & dosificación , Trasplante de Islotes Pancreáticos/métodos , Fragmentos de Péptidos/administración & dosificación , Animales , Autoantígenos/inmunología , Autoinmunidad/inmunología , Linfocitos T CD4-Positivos/inmunología , Diabetes Mellitus Tipo 1/prevención & control , Femenino , Islotes Pancreáticos/inmunología , Ratones , Ratones Endogámicos NOD , Nanopartículas/administración & dosificación , Recurrencia
10.
Diabetes ; 71(12): 2793-2803, 2022 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-36041196

RESUMEN

Hybrid insulin peptides (HIPs) form in pancreatic ß-cells through the formation of peptide bonds between proinsulin fragments and other peptides. HIPs have been identified in pancreatic islets by mass spectrometry and are targeted by CD4 T cells in patients with type 1 diabetes (T1D) as well as by pathogenic CD4 T-cell clones in nonobese diabetic (NOD) mice. The mechanism of HIP formation is currently poorly understood; however, it is well established that proteases can drive the formation of new peptide bonds in a side reaction during peptide bond hydrolysis. Here, we used a proteomic strategy on enriched insulin granules and identified cathepsin D (CatD) as the primary protease driving the specific formation of HIPs targeted by disease-relevant CD4 T cells in T1D. We also established that NOD islets deficient in cathepsin L (CatL), another protease implicated in the formation of disease-relevant HIPs, contain elevated levels of HIPs, indicating a role for CatL in the proteolytic degradation of HIPs. In summary, our data suggest that CatD may be a therapeutic target in efforts to prevent or slow the autoimmune destruction of ß-cells mediated by HIP-reactive CD4 T cells in T1D.


Asunto(s)
Diabetes Mellitus Tipo 1 , Ratones , Animales , Diabetes Mellitus Tipo 1/metabolismo , Insulina , Catepsina D , Proteómica , Ratones Endogámicos NOD , Péptidos , Linfocitos T CD4-Positivos , Insulina Regular Humana
11.
Diabetes ; 70(12): 2860-2870, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34497137

RESUMEN

Recognition of ß-cell antigens by autoreactive T cells is a critical step in the initiation of autoimmune type1 diabetes. A complete protection from diabetes development in NOD mice harboring a point mutation in the insulin B-chain 9-23 epitope points to a dominant role of insulin in diabetogenesis. Generation of NOD mice lacking the chromogranin A protein (NOD.ChgA-/-) completely nullified the autoreactivity of the BDC2.5 T cell and conferred protection from diabetes onset. These results raised the issue concerning the dominant antigen that drives the autoimmune process. Here we revisited the NOD.ChgA-/- mice and found that their lack of diabetes development may not be solely explained by the absence of chromogranin A reactivity. NOD.ChgA-/- mice displayed reduced presentation of insulin peptides in the islets and periphery, which corresponded to impaired T-cell priming. Diabetes development in these mice was restored by antibody treatment targeting regulatory T cells or inhibiting transforming growth factor-ß and programmed death-1 pathways. Therefore, the global deficiency of chromogranin A impairs recognition of the major diabetogenic antigen insulin, leading to broadly impaired autoimmune responses controlled by multiple regulatory mechanisms.


Asunto(s)
Autoinmunidad/genética , Cromogranina A/genética , Diabetes Mellitus Tipo 1/genética , Animales , Presentación de Antígeno/genética , Autoantígenos/inmunología , Autoantígenos/metabolismo , Citoprotección/genética , Citoprotección/inmunología , Diabetes Mellitus Tipo 1/prevención & control , Epítopos de Linfocito T/inmunología , Femenino , Islotes Pancreáticos/inmunología , Islotes Pancreáticos/metabolismo , Ratones , Ratones Endogámicos NOD , Ratones Noqueados
12.
Diabetes ; 70(6): 1334-1346, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33468513

RESUMEN

Antigen-specific immunotherapy (ASIT) offers a targeted treatment of autoimmune diseases that selectively inhibits autoreactive lymphocytes, but there remains an unmet need for approaches that address the limited clinical efficacy of ASIT. Soluble antigen arrays (SAgAs) deliver antigenic peptides or proteins in multivalent form, attached to a hyaluronic acid backbone using either hydrolysable linkers (hSAgAs) or stable click chemistry linkers (cSAgAs). They were evaluated for the ability to block spontaneous development of disease in a nonobese diabetic mouse model of type 1 diabetes (T1D). Two peptides, a hybrid insulin peptide and a mimotope, efficiently prevented the onset of T1D when delivered in combination as SAgAs, but not individually. Relative to free peptides administered at equimolar dose, SAgAs (particularly cSAgAs) enabled a more effective engagement of antigen-specific T cells with greater persistence and induction of tolerance markers, such as CD73, interleukin-10, programmed death-1, and KLRG-1. Anaphylaxis caused by free peptides was attenuated using hSAgA and obviated using cSAgA platforms. Despite similarities, the two peptides elicited largely nonoverlapping and possibly complementary responses among endogenous T cells in treated mice. Thus, SAgAs offer a novel and promising ASIT platform superior to free peptides in inducing tolerance while mitigating risks of anaphylaxis for the treatment of T1D.


Asunto(s)
Diabetes Mellitus Tipo 1/terapia , Péptidos/farmacocinética , Análisis por Matrices de Proteínas , Animales , Autoantígenos/inmunología , Química Clic , Diabetes Mellitus Experimental/inmunología , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 1/inmunología , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Femenino , Inmunoterapia/instrumentación , Inmunoterapia/métodos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones Transgénicos , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/farmacocinética , Péptidos/administración & dosificación , Inducción de Remisión/métodos , Solubilidad , Resultado del Tratamiento
13.
Front Immunol ; 12: 668680, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34113344

RESUMEN

Hybrid Insulin Peptides (HIPs), which consist of insulin fragments fused to other peptides from ß-cell secretory granule proteins, are CD4 T cell autoantigens in type 1 diabetes (T1D). We have studied HIPs and HIP-reactive CD4 T cells extensively in the context of the non-obese diabetic (NOD) mouse model of autoimmune diabetes and have shown that CD4 T cells specific for HIPs are major contributors to disease pathogenesis. Additionally, in the human context, HIP-reactive CD4 T cells can be found in the islets and peripheral blood of T1D patients. Here, we performed an in-depth characterization of the CD4 T cell response to a C-peptide/C-peptide HIP (HIP11) in human T1D. We identified the TCR expressed by the previously-reported HIP11-reactive CD4 T cell clone E2, which was isolated from the peripheral blood of a T1D patient, and determined that it recognizes HIP11 in the context of HLA-DQ2. We also identified a HIP11-specific TCR directly in the islets of a T1D donor and demonstrated that this TCR recognizes a different minimal epitope of HIP11 presented by HLA-DQ8. We generated and tested an HLA-DQ2 tetramer loaded with HIP11 that will enable direct ex vivo interrogation of CD4 T cell responses to HIP11 in human patients and control subjects. Using mass spectrometric analysis, we confirmed that HIP11 is present in human islets. This work represents an important step in characterizing the role of CD4 T cell responses to HIPs in human T1D.


Asunto(s)
Autoantígenos/inmunología , Péptido C/inmunología , Linfocitos T CD4-Positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Insulina/inmunología , Islotes Pancreáticos/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Autoantígenos/metabolismo , Péptido C/metabolismo , Linfocitos T CD4-Positivos/metabolismo , Diabetes Mellitus Tipo 1/sangre , Epítopos , Femenino , Antígenos HLA-DQ/inmunología , Humanos , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Células K562 , Masculino , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo
14.
Diabetes ; 69(7): 1492-1502, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32291282

RESUMEN

T cells isolated from the pancreatic infiltrates of nonobese diabetic mice have been shown to recognize epitopes formed by the covalent cross-linking of proinsulin and secretory granule peptides. Formation of such hybrid insulin peptides (HIPs) was confirmed through mass spectrometry, and responses to HIPs were observed among the islet-infiltrating T cells of pancreatic organ donors and in the peripheral blood of individuals with type 1 diabetes (T1D). However, questions remain about the prevalence of HIP-specific T cells in humans, the sequences they recognize, and their role in disease. We identified six novel HIPs that are recognized in the context of DRB1*04:01, discovered by using a library of theoretical HIP sequences derived from insulin fragments covalently linked to one another or to fragments of secretory granule proteins or other islet-derived proteins. We demonstrate that T cells that recognize these HIPs are detectable in the peripheral blood of subjects with T1D and exhibit an effector memory phenotype. HIP-reactive T-cell clones produced Th1-associated cytokines and proliferated in response to human islet preparations. These results support the relevance of HIPs in human disease, further establishing a novel posttranslational modification that may contribute to the loss of peripheral tolerance in T1D.


Asunto(s)
Cadenas HLA-DRB1/inmunología , Insulina/inmunología , Fragmentos de Péptidos/inmunología , Linfocitos T/inmunología , Linfocitos T CD4-Positivos/inmunología , Reacciones Cruzadas , Diabetes Mellitus Tipo 1/inmunología , Epítopos , Humanos , Insulina/química , Células Secretoras de Insulina/inmunología , Fragmentos de Péptidos/química
15.
Curr Opin Endocrinol Diabetes Obes ; 26(4): 195-200, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31166225

RESUMEN

PURPOSE OF REVIEW: The current review covers recent advances in our knowledge of the newest autoantigen neo-epitopes in type 1 diabetes (T1D): hybrid insulin peptides or HIPs. These ligands for autoreactive T cells are formed by peptide fusion, a novel posttranslational modification process that we first reported in 2016. RECENT FINDINGS: Two major HIPs in the nonobese diabetic mouse model, ligands for diabetogenic CD4 T-cell clones, have been incorporated into tetramers and used to track HIP-reactive T cells during progression of disease. HIPs have also been used in strategies for induction of antigen-specific tolerance and show promise for delaying or reversing disease in the nonobese diabetic mouse. Importantly, CD4 T cells reactive to various HIPs have been detected in the islets and peripheral blood mononuclear cell of T1D patients and newly developed human T-cell clones are being employed to gather more data on the phenotype and function of HIP-reactive T cells in patients. SUMMARY: These new hybrid insulin peptide epitopes may provide the basis for establishing autoreactive T cells as biomarkers of disease and as potential tolerogens for treatment of T1D.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Epítopos de Linfocito T/inmunología , Insulina/inmunología , Animales , Humanos , Ratones , Péptidos/inmunología
16.
Diabetes ; 68(9): 1830-1840, 2019 09.
Artículo en Inglés | MEDLINE | ID: mdl-31175101

RESUMEN

We recently established that hybrid insulin peptides (HIPs) are present in human islets and that T cells reactive to HIPs are found in the residual islets of organ donors with type 1 diabetes (T1D). Here, we investigate whether HIP-reactive T cells are indicative of ongoing autoimmunity in patients with T1D. We used interferon-γ enzyme-linked immune absorbent spot analyses on peripheral blood mononuclear cells (PBMCs) to determine whether patients with new-onset T1D or control subjects displayed T-cell reactivity to a panel of 16 HIPs. We observed that nearly one-half of the patients responded to one or more HIPs. Responses to four HIPs were significantly elevated in patients with T1D but not in control subjects. To characterize the T cells reactive to HIPs, we used a carboxyfluorescein succinimidyl ester-based assay to clone T cells from PBMCs. We isolated six nonredundant, antigen-specific T-cell clones, most of which reacting to their target HIPs in the low nanomolar range. One T-cell clone was isolated from the same patient on two different blood draws, indicating persistence of this T-cell clone in the peripheral blood. This work suggests that HIPs are important target antigens in human subjects with T1D and may play a critical role in disease.


Asunto(s)
Autoantígenos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Insulina/inmunología , Linfocitos T/inmunología , Adolescente , Adulto , Autoinmunidad/inmunología , Niño , Femenino , Humanos , Islotes Pancreáticos/inmunología , Leucocitos Mononucleares/inmunología , Masculino , Adulto Joven
17.
Nat Metab ; 1(5): 509-518, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31423480

RESUMEN

Type 1 diabetes (T1D) is characterized by pancreatic islet infiltration by autoreactive immune cells and a near-total loss of ß-cells1. Restoration of insulin-producing ß-cells coupled with immunomodulation to suppress the autoimmune attack has emerged as a potential approach to counter T1D2-4. Here we report that enhancing ß-cell mass early in life, in two models of female NOD mice, results in immunomodulation of T-cells, reduced islet infiltration and lower ß-cell apoptosis, that together protect them from developing T1D. The animals displayed altered ß-cell antigens, and islet transplantation studies showed prolonged graft survival in the NOD-LIRKO model. Adoptive transfer of splenocytes from the NOD-LIRKOs prevented development of diabetes in pre-diabetic NOD mice. A significant increase in the splenic CD4+CD25+FoxP3+ regulatory T-cell (Treg) population was observed to underlie the protected phenotype since Treg depletion rendered NOD-LIRKO mice diabetic. The increase in Tregs coupled with activation of TGF-ß/SMAD3 signaling pathway in pathogenic T-cells favored reduced ability to kill ß-cells. These data support a previously unidentified observation that initiating ß-cell proliferation, alone, prior to islet infiltration by immune cells alters the identity of ß-cells, decreases pathologic self-reactivity of effector cells and increases Tregs to prevent progression of T1D.


Asunto(s)
Proliferación Celular , Diabetes Mellitus Tipo 1/patología , Sistema Inmunológico/inmunología , Células Secretoras de Insulina/patología , Animales , Diabetes Mellitus Tipo 1/inmunología , Diabetes Mellitus Tipo 1/metabolismo , Progresión de la Enfermedad , Humanos , Ratones
18.
Diabetes ; 67(9): 1836-1846, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29976617

RESUMEN

We recently established that hybrid insulin peptides (HIPs), formed in islet ß-cells by fusion of insulin C-peptide fragments to peptides of chromogranin A or islet amyloid polypeptide, are ligands for diabetogenic CD4 T-cell clones. The goal of this study was to investigate whether HIP-reactive T cells were indicative of ongoing autoimmunity. MHC class II tetramers were used to investigate the presence, phenotype, and function of HIP-reactive and insulin-reactive T cells in NOD mice. Insulin-reactive T cells encounter their antigen early in disease, but they express FoxP3 and therefore may contribute to immune regulation. In contrast, HIP-reactive T cells are proinflammatory and highly diabetogenic in an adoptive transfer model. Because the frequency of antigen-experienced HIP-reactive T cells increases over progression of disease, they may serve as biomarkers of autoimmune diabetes.


Asunto(s)
Autoantígenos/metabolismo , Péptido C/metabolismo , Linfocitos T CD4-Positivos/metabolismo , Cromogranina A/metabolismo , Diabetes Mellitus Tipo 1/inmunología , Polipéptido Amiloide de los Islotes Pancreáticos/metabolismo , Recombinación Genética , Animales , Autoantígenos/química , Autoantígenos/genética , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/metabolismo , Enfermedades Autoinmunes/patología , Enfermedades Autoinmunes/fisiopatología , Autoinmunidad , Biomarcadores/sangre , Péptido C/química , Péptido C/genética , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Células Cultivadas , Cromogranina A/química , Cromogranina A/genética , Células Clonales , Cruzamientos Genéticos , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/patología , Diabetes Mellitus Tipo 1/fisiopatología , Progresión de la Enfermedad , Femenino , Polipéptido Amiloide de los Islotes Pancreáticos/química , Polipéptido Amiloide de los Islotes Pancreáticos/genética , Activación de Linfocitos , Ratones Endogámicos NOD , Ratones Noqueados , Ratones SCID , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/metabolismo , Organismos Libres de Patógenos Específicos
19.
Science ; 351(6274): 711-4, 2016 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-26912858

RESUMEN

T cell-mediated destruction of insulin-producing ß cells in the pancreas causes type 1 diabetes (T1D). CD4 T cell responses play a central role in ß cell destruction, but the identity of the epitopes recognized by pathogenic CD4 T cells remains unknown. We found that diabetes-inducing CD4 T cell clones isolated from nonobese diabetic mice recognize epitopes formed by covalent cross-linking of proinsulin peptides to other peptides present in ß cell secretory granules. These hybrid insulin peptides (HIPs) are antigenic for CD4 T cells and can be detected by mass spectrometry in ß cells. CD4 T cells from the residual pancreatic islets of two organ donors who had T1D also recognize HIPs. Autoreactive T cells targeting hybrid peptides may explain how immune tolerance is broken in T1D.


Asunto(s)
Péptido C/inmunología , Linfocitos T CD4-Positivos/inmunología , Diabetes Mellitus Experimental/inmunología , Diabetes Mellitus Tipo 1/inmunología , Epítopos/inmunología , Células Secretoras de Insulina/inmunología , Secuencia de Aminoácidos , Animales , Péptido C/química , Células Clonales , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Tipo 1/patología , Tolerancia Inmunológica , Células Secretoras de Insulina/patología , Ratones , Ratones Endogámicos NOD , Datos de Secuencia Molecular , Péptidos/química , Péptidos/inmunología
20.
Immunol Res ; 55(1-3): 167-72, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22971988

RESUMEN

Autoreactive CD4 T cells play a central role in the development of type 1 diabetes. The BDC panel of diabetogenic T cell clones was originally isolated from non-obese diabetic mice and has been used to study the role of autoreactive CD4 T cells and T cell autoantigens in the development of diabetes. Recent studies by our group have led to the identification of two new target antigens for clones of this panel. This review describes the proteomic strategy used for antigen identification, the antigens identified, and the potential contribution of post-translational modification to autoantigen generation. In addition, we compare peptide epitopes for the T cell clones and discuss their potential applications in investigating the role of T cell autoantigens in the pathogenesis and regulation of disease.


Asunto(s)
Autoantígenos/inmunología , Linfocitos T CD4-Positivos/inmunología , Diabetes Mellitus Tipo 1/inmunología , Animales , Humanos , Proteómica
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA