Selective delivery of beta cell antigen to dendritic cells in vivo leads to deletion and tolerance of autoreactive CD8+ T cells in NOD mice

Type 1 diabetes (T1D) is an autoimmune disease resulting from defects in central and peripheral tolerance and characterized by T cell-mediated destruction of islet beta cells. Cytotoxic CD8(+) T cells, reactive to beta cell antigens, are required for T1D development in the NOD mouse model of the disease, and CD8(+) T cells specific for beta cell antigens can be detected in the peripheral blood of T1D patients. It has been evident that in nonautoimmune-prone mice, dendritic cells (DCs) present model antigens in a tolerogenic manner in the steady state, e.g., in the absence of infection, and cause T cells to proliferate initially but then to be deleted or rendered unresponsive. However, this fundamental concept has not been evaluated in the setting of a spontaneous autoimmune disease. To do so, we delivered a mimotope peptide, recognized by the diabetogenic CD8(+) T cell clone AI4, to DCs in NOD mice via the endocytic receptor DEC-205. Proliferation of transferred antigen-specific T cells was initially observed, but this was followed by deletion. Tolerance was achieved because rechallenge of mice with the mimotope peptide in adjuvant did not induce an immune response. Thus, targeting of DCs with beta cell antigens leads to deletion of autoreactive CD8(+) T cells even in the context of ongoing autoimmunity in NOD mice with known tolerance defects. Our results provide support for the development of DC targeting of self antigens for treatment of chronic T cell-mediated autoimmune diseases.     

A multiplicity of protein antigens in subcellular fractions of rat insulinoma tissue are able to stimulate T cells obtained from non-obese diabetic mice

Summary Type 1 (insulin-dependent) diabetes mellitus is a T-cell mediated autoimmune disease with a number of different proteins being implicated as target autoantigens. A 38 kDa protein residing in the insulin secretory granule of insulinoma tissue is recognized by T-cell clones from a newly-diagnosed Type 1 diabetic patient. We have investigated the capacity of normal rat pancreatic beta-cell extracts and various subcellular fractions of transplantable RIN tissue to induce proliferation of T cells from non-obese diabetic (NOD) mice and H-2 identical NON · NOD-H-2^g7 control mice. Normal rat islet beta-cell protein fractions induced intense, dose-dependent proliferation of NOD splenic T cells, but only marginal proliferative responses of NON · NOD-H-2^g7 splenic T cells. To further localize the target antigens, four different subcellular fractions from RIN tissue were used as a source of antigen; here in particular the cytosolic proteins showed dose-dependent activation capacity with splenic T cells in NOD animals. These activities were absent in control mice. There was no proliferation after incubation with microsome preparations from other rat endocrine tissues. Purified carboxypeptidase H did not have any stimulatory activity on NOD T cells. Fractionation of the RIN cytosolic proteins showed a large number of different fractions eliciting proliferative activity. These results demonstrate that NOD T cells respond to a large number of potential islet beta-cell target antigens and it will be necessary to utilize NOD T-cell clones to identify the number and nature of these antigens.     

Th1细胞在NOD小鼠糖尿病早期的应用

目的评价Th1细胞对NOD小鼠糖尿病早期变化的作用。方法选择4 w、8 w和16 w的雌性NOD小鼠,采用流式细胞术测定脾Th1细胞,采用免疫组化法检测胰腺内Th1细胞。结果随年龄增加,雌性NOD小鼠脾和胰腺内Th1细胞逐渐增加。结论 Th1细胞参与NOD小鼠糖尿病早期的病理过程。     

Antidiabetogenic MHC class II promotes the differentiation of MHC-promiscuous autoreactive T cells into FOXP3+ regulatory T cells

Polymorphisms in MHC class II molecules, in particular around β-chain position-57 (β57), afford susceptibility/resistance to multiple autoimmune diseases, including type 1 diabetes, through obscure mechanisms. Here, we show that the antidiabetogenic MHC class II molecule I-A^b affords diabetes resistance by promoting the differentiation of MHC-promiscuous autoreactive CD4⁺ T cells into disease-suppressing natural regulatory T cells, in a β56–67-regulated manner. We compared the tolerogenic and antidiabetogenic properties of CD11c promoter-driven transgenes encoding I-A^b or a form of I-A^b carrying residues 56–67 of I-Aβ^g7 (I-A^b-g7) in wild-type nonobese diabetic (NOD) mice, as well as NOD mice coexpressing a diabetogenic and I-A^g7–restricted, but MHC-promiscuous T-cell receptor (4.1). Both I-A transgenes protected NOD and 4.1-NOD mice from diabetes. However, whereas I-A^b induced 4.1-CD4⁺ thymocyte deletion and 4.1-CD4⁺Foxp3⁺ regulatory T-cell development, I-A^b-g7 promoted 4.1-CD4⁺Foxp3⁺ Treg development without inducing clonal deletion. Furthermore, non–T-cell receptor transgenic NOD.CD11cP-I-A^b and NOD.CD11cP-IA^b-g7 mice both exported regulatory T cells with superior antidiabetogenic properties than wild-type NOD mice. We propose that I-A^b, and possibly other protective MHC class II molecules, afford disease resistance by engaging a naturally occurring constellation of MHC-promiscuous autoreactive T-cell clonotypes, promoting their deviation into autoregulatory T cells.     

T lymphocyte response against pancreatic beta cell antigens in fulminant Type 1 diabetes

Aims/hypothesis Fulminant Type 1 diabetes is a novel subtype of Type 1 diabetes that involves the abrupt onset of insulin-deficient hyperglycaemia. This subtype appears to be non-autoimmune because of the absence of diabetes-related autoantibodies in the serum, and of insulitis in pancreatic biopsy specimens. The pathogenesis of the disease is still unknown. In this study, we investigated whether T cell autoimmune responses are involved in fulminant Type 1 diabetes.Methods Cellular immune responses to beta cell autoantigens were studied by enzyme-linked immunospot (ELISPOT) assay in 13 fulminant Type 1 diabetic patients and 49 autoantibody-positive autoimmune Type 1 diabetic patients. Results were compared with those of 18 Type 2 diabetic patients, six secondary diabetic patients (diabetes due to chronic pancreatitis) and 35 healthy controls.Results Nine of 13 (69.2%) GAD-reactive Th1 cells, and three of 12 (25%) insulin-B9-23-reactive Th1 cells were identified in fulminant Type 1 diabetic patients by ELISPOT, as in autoantibody-positive Type 1 diabetic patients. Four fulminant Type 1 diabetic patients possessed the highly diabetes-resistant allele DR2, three of whom had GAD-reactive Th1 cells in the periphery.Conclusions/interpretation Peripheral immune reaction was observed in 69.2% of fulminant Type 1 diabetic patients, indicating that autoreactive T cells might contribute, at least in part, to the development of fulminant Type 1 diabetes.Abbreviations ELISPOT enzyme-linked immunospot - IA-2 tyrosine phosphatase-like protein - ICA islet cell antibodies - mAb monoclonal antibody - PBMC peripheral blood mononuclear cells - PHA phytohaemagglutinin - PPD purified protein derivative     

Cell-mediated cytotoxic islet cell surface antibodies to human pancreatic beta cells

Summary Sera containing islet cell surface antibodies show a complement-dependent cytotoxic reaction against islet cells, but it has not yet been clarified whether islet cell surface antibodies exhibit cell-mediated cytotoxicity to these cells. By ⁵¹Cr release assay we investigated whether islet cell surface antibodies showed a cytotoxic reaction to human pancreatic B cells (JHPI-1 clone) in the presence of normal human lymphocytes. The sera from 14 islet cell surface antibody-positive, 16 islet cell surface antibody-negative Type 1 (insulin-dependent) diabetic patients and 18 islet cell surface antibody-negative healthy subjects were studied. Four sera containing islet cell surface antibodies showed specific cytotoxicity above the mean +3SD value of healthy subjects, and the mean specific cytotoxicity of islet cell surface antibody-positive sera differed significantly from that of both islet cell surface antibody-negative groups. These results suggest that this cell-mediated cytotoxic mechanism may play an important role in the pathogenesis of Type 1 diabetes.     

Turning human epidermis into pancreatic endoderm

OBJECTIVE: Human embryonic stem (hES) cells can be differentiated into pancreatic endoderm structures in vitro. The study was performed to determine whether induced pluripotent stem (iPS) cells can be differentiated into similar structures with comparable efficiency. METHODS: We compared the ability of hES cells and iPS cells derived from human epidermal keratinocytes to progressively differentiate into pancreatic endoderm. Human foreskin keratinocytes were reprogrammed to pluripotency by transduction with retroviruses encoding Oct4, Sox2, and Klf4. The resulting keratinocyte-derived iPS (KiPS) cell lines and a hES cell line were subjected to a modified pancreatic endoderm differentiation protocol. Cells and embryoid-body structures derived from both hES and KiPS cells were compared at different stages of development for expression of stem cell and differentiation markers, including Sox2, Oct4, Mixl1, Brachyury, Gsc, FoxA2, Sox17, Hnf4α, Hnf1β, Nkx2.2, Nkx6.1, Hex, Isl1, Pdx1, and Slc2A, via Taqman real-time PCR, flow-cytometry, and/or immunocytochemistry. RESULTS: hES cells and KiPS cells expressed similar levels of the stem cell factors Sox2 and Oct4. Upon differentiation, both cell types underwent remarkably similar changes in gene expression. They acquired the definitive endoderm markers Sox17 and FoxA2. Most Sox17⁺ and FoxA2⁺ cells co-expressed Hnf4α and Hnf1β, found in the primitive gut tube, a pancreas precursor. Most FoxA2⁺ cells were also Pdx1⁺, and many expressed Nkx2.2, Nkx6.1, and Isl1. CONCLUSIONS: Keratinocyte-derived iPS cells can be differentiated into pancreatic endoderm, and the efficiency of this process is comparable to that seen for hES cells. Thus keratinocytes have the potential to serve as a source of patient-specific pancreatic endoderm for transplantation.     

Fresh human islet transplantation to replace pancreatic endocrine function in type 1 diabetic patients

The aim of this study was to evaluate the feasibility of islet allografts in patients with type 1 diabetes melititus. Six patients received human islets from either one or two donors via the portal vein, after (n=4) or simultaneously with (n=2) a kidney graft. The patients with functioning kidney grafts (nos. 1–4) were already on triple immunosuppressive therapy (cyclosporine A, azathioprine, prednisone). Prednisone was increased to 60 mg/day for 15 days after the islet transplant in patient 1. Patient 2–4 and the patients who underwent a simultaneous kidney-islets graft (nos. 5, 6) also received antilymphocyte globulin. Intravenous insulin was given for the first 15 days to maintain blood glucose concentrations within the normal range. Patient 1 rejected the islets within 15 days of islet transplantation. In patient 2, a 25% reduction in insulin requirement was observed and 12 months after transplantation post-prandial serum C-peptide was 1.5 ng/ml. In patient 3, the insulin requirement decreased from 40 to 8 units/day with a post-prandial serum C-peptide of 4.1 ng/ml 12 months after islet transplantation. In patient 4 the post-prandial secretion of C-peptide increased to 6.4 ng/ml. Six months after the islet infusion, insulin therapy was discontinued and HbA_1c, 24-h metabolic profile and oral glucose tolerance test remained within the normal range. He had remained off insulin for 5 months until recently, when foot gangrene paralleled a worsening of post-prandial glycaemic control. Twelve months after transplantation he is receiving 8 units insulin/day. Patients 5 and 6 received a simultaneous kidney and islet graft and 6 months after transplantation their post-prandial C-peptide secretion peaks were 2.5 and 1.9 ng/ml respectively. Their daily insulin requirement was not significantly modified. In conclusion, these results show that an adequate number of human islets injected intraportally in type 1 diabetic patients can replace the pancreatic endocrine function and can lead to insulin independence.     

Incretin-based therapy and pancreatic beta cells

Type 2 diabetes (T2D) is a complex, progressive disease with life-threatening complications and one of the most serious public-health problems worldwide. The two main mechanisms of T2D pathogenesis are pancreatic beta cell dysfunction and insulin resistance. It is now recognized that pancreatic beta cell dysfunction is a necessary factor for T2D development. Traditional therapies for controlling blood glucose are suboptimal as they fail to meet target goals for many patients. Glucagon-like peptide-1 receptor agonists (GLP1RA) and dipeptidyl peptidase-4 inhibitors (DPP4I) are an attractive class of therapy because they reduce blood glucose by targeting the incretin hormone system and, in particular, have the potential to positively affect pancreatic beta cell biology. This review outlines our current understanding of pancreatic beta cell incretin system dysfunction in T2D and summarizes recent evidence of the effect of incretin-based therapies on beta cell function and mass. Incretin-based therapies have shown strong evidence for beneficial effects on beta cell function and mass in animal studies. In humans, incretin-based therapies are effective glucose-lowering agents, but further study is still required to evaluate their long-term effects on beta cell function and safety as well as beta cell mass expansion.     

调节性T细胞在1型糖尿病和胰岛移植中的作用

调节性T细胞是一种免疫抑制性细胞,在维持免疫耐受中起重要作用.研究相继发现了多种调节性T细胞的表面标记和调节性T细胞的作用机制.调节性T细胞的数量和(或)功能缺陷与1型糖尿病的发生、发展密切相关.输注调节性T细胞可以预防和治疗1型糖尿病,延长移植胰岛的存活时间和改善移植物功能.目前,关于调节性T细胞治疗的临床试验研究已经开展,如果后续实验能证实调节性T细胞体内输注治疗的安全性及有效性,调节性T细胞免疫治疗将成为治疗1型糖尿病和预防胰岛移植后免疫排斥的有效方法.     

CXCL1和CXCL2在ARDS小鼠肺组织表达的变化规律及评价

目的 观察ARDS小鼠模型肺组织内中性粒细胞趋化因子CXCL1和CXCL2的表达量及随时间的变化规律,探究其在小鼠肺组织损伤过程中的作用.方法 42只雄性C57BL/6小鼠随机分为对照组和脂多糖(LPS)刺激15 min、30 min、6h、24 h、3d、7d组,每组6只.HE染色观察小鼠肺组织形态结构改变,并计算肺损伤评分;RT-PCR法检测小鼠肺组织中CXCL1和CXCL2的mRNA表达水平;酶联免疫吸附试验法检测小鼠BALF中CXCL1和CXCL2浓度的变化,并计算中性粒细胞数目.结果 与对照组相比,LPS刺激组小鼠(ARDS小鼠)肺泡及间质组织正常结构破坏,炎症浸润明显,肺损伤评分升高,3d时达最高值;ARDS小鼠肺组织中CXCL1和CXCL2 mRNA表达水平显著升高,分别在LPS滴注后30 min和6h时达峰值;同时ARDS小鼠BALF中CXCL1和CXCL2浓度也明显升高,变化趋势与肺组织中CXCL1和CXCL2 mRNA水平变化相一致;且BALF内中性粒细胞数目显著增加,在LPS滴注6h时达峰值.结论 LPS诱导产生的ARDS小鼠模型中的中性粒细胞数目及CXCL1、CXCL2等趋化因子的表达量均随着时间表现出类似的“驼峰样”改变,提示中性粒细胞趋化因子在ARDS炎症性损伤的形成及发展中扮演着重要角色.     

Long-term follow-up after transplantation of insulin-producing pancreatic islets into patients with Type 1 (insulin-dependent) diabetes mellitus

Summary Purified human islets and a kidney from the same donor were transplanted into four patients with Type 1 (insulin-dependent) diabetes mellitus. Two of the patients received additional islets that were isolated from multiple donors, cryopreserved, and stored in a tissue bank. The islets were embolized into the liver via the portal vein. Immunosuppression was induced with antilymphocyte globulin and maintained with azathioprine, prednisone and cyclosporine. In the first two patients, fasting serum C-peptide rose to levels of 0.5–2.0 ng/ml during the first 4–8 weeks and mixed meal feeding elicited increases to 2–3 ng/ml. C-peptide secretion persisted for 8 months, but at progressively lower levels and insulin therapy could not be withdrawn. In the next two patients who received cryopreserved islets in addition to fresh islets, serum C-peptide levels (fasting/post-meal) rose to 4–7 ng/ml and serum glucose was more stable, allowing withdrawal of insulin therapy after 69 days in one patient, and reduced insulin doses in the other. The insulin-independent patient has maintained normal fasting glucose, glycosylated haemoglobin, and oral glucose tolerance at 1 year following cessation of daily insulin therapy. Episodes of renal graft rejection occurred in three patients, including the insulin-independent patient. High-dose steroid therapy reversed the rejection in all instances, with apparent preservation of C-peptide secretion. These data show that transplantation of purified freshly-prepared and cryopreserved islets into Type 1 diabetic patients results in prolonged insulin secretion, and that sufficient function could be provided in one patient to sustain euglycaemia in the absence of insulin therapy at 1 year of follow-up.     

Inhibition of insulin-specific autoreactive T-cells by sulphatide which is variably expressed in beta cells

Abstract Aims/hypothesis. Sulphatide and insulin are present in the secretory granules and at the surface of beta cells in islets of Langerhans. Insulin autoantibodies and T-cell reactivity against insulin exist during the development of Type I (insulin-dependent) diabetes during which active beta cells may be more vulnerable than passive. Our aims were to examine the presence of sulphatide in active and passive beta cells and to clarify whether sulphatide influences the direct autoimmunity against insulin. Methods. We incubated rat islets in 2.8, 11.0 or 20.0 mmol/l glucose for 24 h and did an electron microscopic evaluation after labelling with a specific anti-sulphatide monoclonal antibody. The reactivity of an insulin-specific T-cell clone isolated from a patient with Type I diabetes, was examined using insulin or insulin B-chain (B11–27) peptide incubated together with sulphatide. Results. We detected lower amounts of sulphatide per insulin secretory granule in active compared with passive beta cells (p = 0.003). The presence of sulphatide in vitro at doses of 43–8.3 μmol/l resulted in greatly reduced proliferation (median 3.4 % of control value, p = 0.0004) of the insulin-specific T-cell clone. No inhibition was found using the precursor of sulphatide, galactosylceramide, or GM1. Sulphatide did not reduce non-aspecific proliferation (induced by phorbol myristate acetate plus anti-CD3) or specific proliferation induced by insulin peptide. Conclusion/interpretation. These results imply that sulphatide possibly affect processing of the insulin molecule. Sulphatide which has been reported to interfere with phagosome-lysosome fusion, conceivably interacts with insulin. We hypothesize a (patho)physiological role of sulphatide, variably expressed in beta cells, by reducing the antigenicity of insulin. [Diabetologia (1999) 42: 1212–1218] Received: 25 March 1999 and in revised form:1 June 1999     

The prevalence of enteroviral capsid protein vp1 immunostaining in pancreatic islets in human type 1 diabetes

Aims/hypothesis  Evidence that the beta cells of human patients with type 1 diabetes can be infected with enterovirus is accumulating, but it remains unclear whether such infections occur at high frequency and are important in the disease process. We have now assessed the prevalence of enteroviral capsid protein vp1 (vp1) staining in a large cohort of autopsy pancreases of recent-onset type 1 diabetic patients and a range of controls. Methods  Serial sections of paraffin-embedded pancreatic autopsy samples from 72 recent-onset type 1 diabetes patients and up to 161 controls were immunostained for insulin, glucagon, vp1, double-stranded RNA activated protein kinase R (PKR) and MHC class I. Results  vp1-immunopositive cells were detected in multiple islets of 44 out of 72 young recent-onset type 1 diabetic patients, compared with a total of only three islets in three out of 50 neonatal and paediatric normal controls. vp1 staining was restricted to insulin-containing beta cells. Among the control pancreases, vp1 immunopositivity was also observed in some islets from ten out of 25 type 2 diabetic patients. A strong correlation was established between islet cell vp1 positivity and PKR production in insulin-containing islets of both type 1 and type 2 diabetic patients, consistent with a persistent viral infection of the islets. Conclusions/interpretation  Immunoreactive vp1 is commonly found in the islets of recent-onset type 1 diabetes patients, but only rarely in normal paediatric controls. vp1 immunostaining was also observed in some islets of type 2 diabetes patients, suggesting that the phenomenon is not restricted to type 1 diabetes patients. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Cross-sectional associations of C-reactive protein with vascular risk factors and vascular complications in the DCCT/EDIC cohort

OBJECTIVE: To determine the relationships between C-reactive protein (CRP) levels and features of Type 1 diabetes. RESEARCH DESIGN AND METHODS: Serum CRP was measured by nephelometry in a cross-sectional study of the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) cohort (n=983) and nondiabetic subjects (n=71). RESULTS: CRP levels [geometric mean (95% CI)] were higher in diabetic than in control subjects, 1.6 (1.5-1.7) vs. 1.2 (1.1-1.5) mg/l, P=.019. CRP was higher in diabetic women (n=438) than in men (n=545) [2.0 (1.8-2.3) vs. 1.3 (1.2-1.5), P<.001]. Diabetic subjects formerly in the DCCT intensive treatment group had higher CRP levels than those who were randomized to the conventional treatment group [1.8 (1.6-1.9), n=479 vs. 1.5 (1.3-1.6), n=456, P=.010], attributable to greater BMI in the prior intensive group. In diabetes, CRP correlated with HbA(1c) (r=0.13, P<.0001) and with insulin resistance traits: BMI (r=0.34, P<.0001), waist-to-hip ratio (WHR; males: r=0.35, P<.0001; females: r=0.22, P<.0001), diastolic blood pressure (r=0.07, P=.025), triglycerides (r=0.19, P<.0001), apoB (r=0.22, P<.0001), LDL particle concentration (r=0.26, P<.0001), and LDL particle size (r=-0.22, P<.0001). CRP was not associated with complications. Significant independent predictors of CRP in diabetes were gender, BMI, WHR, concurrent HbA(1c), and oral contraceptive pill use. CONCLUSIONS: CRP was elevated relative to nondiabetic subjects, and in diabetes was higher in females. Elevated CRP in Type 1 diabetes was associated with poor glycemic control, larger body habitus, and other factors that comprise the insulin resistance syndrome. Nevertheless, CRP levels were not associated with complications. Longitudinal studies are warranted.     

姜黄素对NOD糖尿病小鼠Th1细胞和CD4^+Treg细胞的作用

目的研究姜黄素对Th1细胞和CD4^+Treg细胞的作用,探讨姜黄素对非肥胖糖尿病(NOD)小鼠的治疗作用。方法将10周龄雌性NOD小鼠分为对照组和姜黄素组,分别用溶剂或姜黄素灌胃。第14周时测血糖。第20周时,流式细胞术分析外周血Th1细胞和CD4^+Treg细胞,分析胸腺CD4^+ CD8^-T细胞、CD8+CD4^-T细胞及CD4^+Treg细胞;分选脾CD4^+Treg细胞用于检测其抑制功能。结果姜黄素组血糖正常比例高于对照组。姜黄素组Th1细胞比例显著低于对照组(P<0.05),CD4^+Treg细胞比例与对照组差异无统计学意义(P>0.05),CD4^+Treg/Th1显著高于对照组(P<0.05)。姜黄素组胸腺CD4^+CD8^-T细胞、CD8^+CD4^-T细胞及CD4^+Treg细胞比例与对照组差异无统计学意义(P>0.05),胸腺总细胞数显著高于对照组(P<0.05)。姜黄素组CD4^+Treg细胞的抑制功能明显高于对照组(P<0.05)。结论姜黄素降低NOD小鼠外周Th1细胞、增加CD4^+Treg细胞抑制功能、缓解胸腺退化,延缓了NOD小鼠的高血糖症状。     

Glycosylation of human fibrinogen in vivo

Summary Fibrinogen was purified from plasma from 22 nondiabetic and 26 poorly controlled Type 1 (insulin-dependent) diabetic subjects. In non-diabetic subjects, 0.95±0.17 mol glucose was bound per mol fibrinogen, whereas in the diabetic subjects 1.33±0.21 mol glucose was bound per mol fibrinogen (mean ± SD, p<0.001). Comparison of the amount of bound glucose, when estimated by two different methods, suggested that lysine is the site of glycosylation. It is currently unknown whether this increased glycosylation of fibrinogen alters its function.