Anti-CD3 clinical trials in type 1 diabetes mellitus

Anti-CD3 monoclonal antibodies in treatment of type 1 diabetes: a systematic review and meta-analysis

PURPOSE

This meta-analysis aimed to assess the efficacy and safety of anti-CD3 monoclonal antibodies (mAbs) for type 1 diabetes.

METHODS

We searched PubMed, Embase and Cochrane until 23 February 2023 for randomized controlled trials that compared anti-CD3 mAbs with placebo in type 1 diabetes. The primary outcome was the area under the curve (AUC) of C-peptide, daily insulin dose or HbA1c.

RESULTS

Totally 12 trials that included 1870 participants were eligible for inclusion in the review. Compared with the control group, anti-CD3 mAbs increased AUC of C-peptide at 1 year (P = 0.0005, MD 0.14, 95% CI [0.06, 0.22], I2 = 94%), and 2 years (P = 0.0003, MD 0.20, 95% CI [0.09, 0.30], I2 = 88%). The use of anti-CD3 mAbs decreased insulin use at 1 year (P = 0.001, MD -0.09, 95% CI [-0.15, -0.04], I2 = 90%), and 2 years (P < 0.00001, MD -0.18, 95% CI [-0.25, -0.12], I2 = 86%). But there was no statistically significant effect on HbA1c levels. Vomiting, nausea, rash, pyrexia and headache were reported more frequently with anti-CD3 mAbs than with placebo. However, incidence of total adverse events and serious adverse events was similar when comparing anti-CD3 mAbs with placebo.

CONCLUSIONS

Our results suggest that anti-CD3 mAbs were a potential therapy for improving AUC of C-peptide and insulin use in type 1 diabetes.

Nanotargeted Delivery of Immune Therapeutics in Type 1 Diabetes

Immune therapeutics holds great promise in the treatment of type 1 diabetes (T1D). Nonetheless, their progress is hampered by limited efficacy, equipoise, or issues of safety. To address this, a novel and specific nanodelivery platform for T1D that targets high endothelial venules (HEVs) presented in the pancreatic lymph nodes (PLNs) and pancreas is developed. Data indicate that the pancreata of nonobese diabetic (NOD) mice and patients with T1D are unique in their expression of newly formed HEVs. Anti-CD3 mAb is encapsulated in poly(lactic-co-glycolic acid)-poly(ethylene glycol) nanoparticles (NPs), the surfaces of which are conjugated with MECA79 mAb that recognizes HEVs. Targeted delivery of these NPs improves accumulation of anti-CD3 mAb in both the PLNs and pancreata of NOD mice. Treatment of hyperglycemic NOD mice with MECA79-anti-CD3-NPs results in significant reversal of T1D compared to those that are untreated, treated with empty NPs, or provided free anti-CD3. This effect is associated with a significant reduction of T effector cell populations in the PLNs and a decreased production of pro-inflammatory cytokine in the mice treated with MECA79-anti-CD3-NPs. In summary, HEV-targeted therapeutics may be used as a means by which immune therapeutics can be delivered to PLNs and pancreata to suppress autoimmune diabetes effectively.

Immune cell infiltration in the pancreas of type 1, type 2 and type 3c diabetes

The different types of diabetes differ in disease pathogenesis but share the impairment or loss of β-cell function leading to chronic hyperglycaemia. While immune cells are present throughout the whole pancreas in normality, their number and activation is increased in diabetes. Different patterns and composition of inflammation could be observed in type 1, type 2 and type 3c diabetes. Immune cells, pancreatic stellate cells and fibrosis were present in the islet microenvironment and could add to β-cell dysfunction and therefore development and progression of diabetes. First studies investigating the use of anti-inflammatory drugs demonstrate their ability to rescue remaining β-cell function and their potential benefit in diabetes treatment. This article provides an overview of immune cell infiltrates in different types of diabetes, highlights the knowledge of their impact on β-cell function and introduces the potential of immunomodulatory strategies.

Teplizumab: type 1 diabetes mellitus preventable?

Type 1 diabetes mellitus (T1DM) is an autoimmune condition driven by T lymphocytes that specifically declines the function of beta cells of pancreas. Immunological treatments aim to stop this decline in β-cell function thus preventing TIDM. Although TIDM occur at any age, it is one of the most common chronic disorders in children. T1DM accounts for 5 to 10% of all cases of diabetes amounting 21-42 million affected persons. Teplizumab is a novel drug recently approved by the US FDA for the treatment of T1DM. This drug reduces abnormal glucose tolerance who are at high risk for developing T1DM and have antibodies suggesting an immunological attack on their pancreas. A 14-day infusion of the drug prevents T cells' attack of the insulin-producing cells of the pancreas. Adverse events due to teplizumab reported so far mild and of limited duration. This review gives an overview of the preclinical and clinical research on teplizumab for their role in new-onset T1DM.

CAR Treg: A new approach in the treatment of autoimmune diseases

Regulatory T cells (Tregs) have the role of regulating self-tolerance, and suppressing immune responses. Defects in Treg function and number can lead to in loss of tolerance or autoimmune disease. To treat or control autoimmune diseases, one of the options is to develop immune tolerance for Tregs cell therapy, which includes promotion and activation. Recently, cell-based treatment as a promising approach to increase cells function and number has been developed. Cell therapy by chimeric T antigen receptor (CAR-T) cells has shown significant efficacy in the treatment of leukemia, which has led researchers to use CAR-T cells in other diseases like autoimmune diseases. Here, we describe the existing treatments for autoimmune diseases and the available treatments based on Treg, their benefits and restrictions for implementation in clinical trials. We also discussed potential solutions to overcome these limitations. It seems novel designs of CARs to be new hope for autoimmune diseases and expected to be a potential cure option in a wide array of disease in the future. Therefore, it is very important to address this issue and increase information about it.

Coreceptor therapy has distinct short- and long-term tolerogenic effects intrinsic to autoreactive effector T cells

Immunotherapies are needed in the clinic that effectively suppress beta cell autoimmunity and reestablish long-term self-tolerance in type 1 diabetes. We previously demonstrated that nondepleting αCD4 and αCD8α antibodies establish rapid and indefinite remission in recent-onset diabetic NOD mice. Diabetes reversal by coreceptor therapy (CoRT) is induced by suppression of pathogenic effector T cells (Teff) and the selective egress of T cells from the pancreatic lymph nodes and islets that remain free of infiltration long-term. Here, we defined CoRT-induced events regulating early Teff function and pancreatic residency, and long-term tolerance. TCR-driven gene expression controlling autoreactive Teff expansion and proinflammatory activity was suppressed by CoRT, and islet T cell egress was sphingosine-1 phosphate-dependent. In both murine and human T cells, CoRT upregulated the Foxo1 transcriptional axis, which in turn was required for suppression and efficient pancreatic egress of Teff. Interestingly, long-term tolerance induced in late-preclinical NOD mice was marked by reseeding of the pancreas by a reduced CD8+ Teff pool exhibiting an exhausted phenotype. Notably, PD-1 blockade, which rescues exhausted Teff, resulted in diabetes onset in protected animals. These findings demonstrate that CoRT has distinct intrinsic effects on Teff that impact events early in induction and later in maintenance of self-tolerance.

NOD Mice-Good Model for T1D but Not Without Limitations

The nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D) was discovered by coincidence in the 1980s and has since been widely used in the investigation of T1D and diabetic complications. The current in vivo study was originally designed to prospectively assess whether hyperglycemia onset is associated with physical destruction or functional impairment of beta cells under inflammatory insult during T1D progression in diabetes-prone female NOD mice. Prediabetic 16- to 20-wk-old NOD mice were transplanted with green fluorescent protein (GFP)-expressing reporter islets in the anterior chamber of the eye (ACE) that were monitored longitudinally, in addition to glycemia, with and without immune modulation using anti-CD3 monoclonal antibody therapy. However, there was an early and vigorous immune reaction against the GFP-expressing beta cells that lead to their premature destruction independent of autoimmune T1D development in progressor mice that eventually became hyperglycemic. This immune reaction also occurred in nonprogressor NOD recipients. These findings showed a previously unknown reaction of NOD mice to GFP that prevented achieving the original goals of this study but highlighted a new feature of the NOD mice that should be considered when designing experiments using this model in T1D research.

Intestinal Microbiota in Common Chronic Inflammatory Disorders Affecting Children

The incidence and prevalence rate of chronic inflammatory disorders is on the rise in the pediatric population. Recent research indicates the crucial role of interactions between the altered intestinal microbiome and the immune system in the pathogenesis of several chronic inflammatory disorders in children, such as inflammatory bowel disease (IBD) and autoimmune diseases, such as type 1 diabetes mellitus (T1DM) and celiac disease (CeD). Here, we review recent knowledge concerning the pathogenic mechanisms underlying these disorders, and summarize the facts suggesting that the initiation and progression of IBD, T1DM, and CeD can be partially attributed to disturbances in the patterns of composition and abundance of the gut microbiota. The standard available therapies for chronic inflammatory disorders in children largely aim to treat symptoms. Although constant efforts are being made to maximize the quality of life for children in the long-term, sustained improvements are still difficult to achieve. Additional challenges are the changing physiology associated with growth and development of children, a population that is particularly susceptible to medication-related adverse effects. In this review, we explore new promising therapeutic approaches aimed at modulation of either gut microbiota or the activity of the immune system to induce a long-lasting remission of chronic inflammatory disorders. Recent preclinical studies and clinical trials have evaluated new approaches, for instance the adoptive transfer of immune cells, with genetically engineered regulatory T cells expressing antigen-specific chimeric antigen receptors. These approaches have revolutionized cancer treatments and have the potential for the protection of high-risk children from developing autoimmune diseases and effective management of inflammatory disorders. The review also focuses on the findings of studies that indicate that the responses to a variety of immunotherapies can be enhanced by strategic manipulation of gut microbiota, thus emphasizing on the importance of proper interaction between the gut microbiota and immune system for sustained health benefits and improvement of the quality of life of pediatric patients.

Progress in the pathogenesis of thyroid-associated ophthalmopathy and new drug development

Thyroid-associated ophthalmopathy (TAO) is the most common extrathyroidal manifestation of toxic diffuse goiter (Graves' disease), also known as Graves' ophthalmopathy/orbitopathy. As an organ-specific autoimmune disease, the pathogenesis of TAO is still unclear. In recent years, great progress has been made in revealing the mechanism of TAO. Various biological and immunosuppressive agents have emerged in an endless stream, showing encouraging results. Strengthening the basic research, establishing ideal animal models, deeply understanding the pathogenesis, and developing novel targeted drugs are of great significance to guide the clinical diagnosis and management of TAO and improve the prognosis of patients.

Beta cell-specific CD8+ T cells maintain stem cell memory-associated epigenetic programs during type 1 diabetes

The pool of beta cell-specific CD8⁺ T-cells in type 1 diabetes (T1D) sustains an autoreactive potential despite having access to a constant source of antigen. To investigate the long-lived nature of these cells, we established a DNA methylation-based T cell “multipotency index” and found that beta cell-specific CD8⁺ T-cells retained a stem-like epigenetic multipotency score. Single cell ATAC-seq analysis confirmed the co-existence of naive and effector-associated epigenetic programs in individual beta cell-specific CD8⁺ T-cells. Assessment of beta cell-specific CD8⁺ T-cell anatomical distribution and the establishment of stem-associated epigenetic programs revealed that self-reactive CD8⁺ T-cells isolated from murine lymphoid tissue retained developmentally plastic phenotypic and epigenetic profiles relative to the same cells isolated from the pancreas. Collectively, these data provide new insight into the longevity of beta cell-specific CD8⁺ T cell responses, and document the utility of this novel methylation-based multipotency index for investigating human and mouse CD8⁺ T-cell differentiation.

Thyroid eye disease: current and potential medical management

INTRODUCTION

Thyroid eye disease (TED) is the most frequent extra-thyroid manifestation of Graves' disease and it is more frequent in middle age and in female gender. Nowadays, the causal mechanisms of this disease are not completely understood, but the current available studies suggest that the main causative factor is the thyroid stimulating hormone receptor.

MATERIALS AND METHODS

To collect reports on TED medical management, a thorough literature search was performed in PubMed database. An additional search was made in Google Scholar to complete the collected items.

RESULTS

Among the indentified risk factors, tobacco habit is the most relevant. The main criteria to choose a suitable treatment are the activity and severity of the disease. Support measures can be used to improve the patient's symptoms in any phase of the disease. There is a large number of drugs proposed to manage TED, although with different reported rates of success.

CONCLUSIONS

Currently, the drugs of choice are corticosteroids in moderate-to-severe and in sight-threatening forms. The main problem of corticosteroids is their spectrum of side effects. Therefore, other alternatives are being suggested for medical management of this disease. The efficacy of these alternatives remains unclear.

[Monoclonal antibodies in cardiovascular diseases and metabolic disorders today]

The use of monoclonal antibodies in cardiovascular diseases and metabolic disorders is still in its infancy. Recent development of anti-PCSK9 monoclonal antibodies for the treatment of dyslipidemia and of patients in secondary prevention is a breakthrough in the field. Anti- PCSK9 antibodies significantly improved LDL cholesterol reduction in patients with familial hypercholesterolemia. These antibodies have also demonstrated a significant reduction of clinical events in patients with previously established atherosclerotic disease such as myocardial infarction, ischemia stroke or peripheral artery disease. Other targets are under investigation such as inflammatory cells and cytokines to reduce atherosclerosis or myocardial lesions following myocardial infarction.

Chemokines as Drivers of the Autoimmune Destruction in Type 1 Diabetes: Opportunity for Therapeutic Intervention in Consideration of an Optimal Treatment Schedule

Type 1 diabetes (T1D) is mainly precipitated by the destruction of insulin-producing β-cells in the pancreatic islets of Langerhans by autoaggressive T cells. The etiology of the disease is still not clear, but besides genetic predisposition the exposure to environmental triggers seems to play a major role. Virus infection of islets has been demonstrated in biopsies of T1D patients, but there is still no firm proof that such an infection indeed results in islet-specific autoimmunity. However, virus infection results in a local inflammation with expression of inflammatory factors, such as cytokines and chemokines that attract and activate immune cells, including potential autoreactive T cells. Many chemokines have been found to be elevated in the serum and expressed by islet cells of T1D patients. In mouse models, it has been demonstrated that β-cells express chemokines involved in the initial recruitment of immune cells to the islets. The bulk load of chemokines is however released by the infiltrating immune cells that also express multiple chemokine receptors. The result is a mutual attraction of antigen-presenting cells and effector immune cells in the local islet microenvironment. Although there is a considerable redundancy within the chemokine ligand-receptor network, a few chemokines, such as CXCL10, seem to play a key role in the T1D pathogenesis. Studies with neutralizing antibodies and investigations in chemokine-deficient mice demonstrated that interfering with certain chemokine ligand-receptor axes might also ameliorate human T1D. However, one important aspect of such a treatment is the time of administration. Blockade of the recruitment of immune cells to the site of autoimmune destruction might not be effective when the disease process is already ongoing. By that time, autoaggressive cells have already arrived in the islet microenvironment and a blockade of migration might even hold them in place leading to accelerated destruction. Thus, an anti-chemokine therapy makes most sense in situations where the cells have not yet migrated to the islets. Such situations include treatment of patients at risk already carrying islet-antigen autoantibodies but are not yet diabetic, islet transplantation recipients, and patients that have undergone a T cell reset as occurring after anti-CD3 antibody treatment.

Immunological Aspects of Graves' Ophthalmopathy

The body's autoimmune process is involved in the development of Graves' disease (GD), which is manifested by an overactive thyroid gland. In some patients, autoreactive inflammatory reactions contribute to the development of symptoms such as thyroid ophthalmopathy, and the subsequent signs and symptoms are derived from the expansion of orbital adipose tissue and edema of extraocular muscles within the orbit. The autoimmune process, production of antibodies against self-antigens such as TSH receptor (TSHR) and IGF-1 receptor (IGF-1R), inflammatory infiltration, and accumulation of glycosaminoglycans (GAG) lead to edematous-infiltrative changes in periocular tissues. As a consequence, edema exophthalmos develops. Orbital fibroblasts seem to play a crucial role in orbital inflammation, tissue expansion, remodeling, and fibrosis because of their proliferative activity as well as their capacity to differentiate into adipocytes and myofibroblasts and production of GAG. In this paper, based on the available medical literature, the immunological mechanism of GO pathogenesis has been summarized. Particular attention was paid to the role of orbital fibroblasts and putative autoantigens. A deeper understanding of the pathomechanism of the disease and the involvement of immunological processes may give rise to the introduction of new, effective, and safe methods of treatment or monitoring of the disease activity.

Stimulator of interferon genes agonists attenuate type I diabetes progression in NOD mice

Reagents that activate the signaling adaptor stimulator of interferon genes (STING) suppress experimentally induced autoimmunity in murine models of multiple sclerosis and arthritis. In this study, we evaluated STING agonists as potential reagents to inhibit spontaneous autoimmune type I diabetes (T1D) onset in non-obese diabetic (NOD) female mice. Treatments with DNA nanoparticles (DNPs), which activate STING when cargo DNA is sensed, delayed T1D onset and reduced T1D incidence when administered before T1D onset. DNP treatment elevated indoleamine 2,3 dioxygenase (IDO) activity, which regulates T-cell immunity, in spleen, pancreatic lymph nodes and pancreas of NOD mice. Therapeutic responses to DNPs were partially reversed by inhibiting IDO and DNP treatment synergized with insulin therapy to further delay T1D onset and reduce T1D incidence. Treating pre-diabetic NOD mice with cyclic guanyl-adenyl dinucleotide (cGAMP) to activate STING directly delayed T1D onset and stimulated interferon-αβ (IFN-αβ), while treatment with cyclic diguanyl nucleotide (cdiGMP) did not delay T1D onset or induce IFN-αβ in NOD mice. DNA sequence analyses revealed that NOD mice possess a STING polymorphism that may explain differential responses to cGAMP and cdiGMP. In summary, STING agonists attenuate T1D progression and DNPs enhance therapeutic responses to insulin therapy.

Anti-CD3 Antibody for the Prevention of Type 1 Diabetes: A Story of Perseverance

Type 1 diabetes (T1D) is an autoimmune disease characterized by an insulin deficiency. Ever since the discovery of insulin almost 100 years ago, patients with T1D have relied on multiple daily insulin injections to survive an otherwise deadly disease. Despite decades of research and clinical trials, no treatment exists yet to prevent or cure T1D. A recent prevention trial using the anti-CD3 antibody teplizumab in individuals at a high risk of developing T1D has provided the first piece of evidence that a safe and transient intervention may be able to delay disease. In this Perspective, we review the 40-year long history of anti-CD3 and discuss how this antibody became a candidate for the treatment of autoimmune diabetes. The path that leads to its use in this latest clinical trial for T1D has been winding and strewn with setbacks. The molecular actions of the anti-CD3 antibody that target T lymphocytes are well-understood, but its systemic effect on immune function has proven more difficult to unravel. Moreover, preclinical data suggested that the utility of anti-CD3 for the prevention of T1D may be limited. However, the latest clinical data are encouraging and exemplify how a basic discovery can, decades later and with much perseverance, become a promising therapeutic candidate.

Gene expression profile of human T cells following a single stimulation of peripheral blood mononuclear cells with anti-CD3 antibodies

Background

Anti-CD3 immunotherapy was initially approved for clinical use for renal transplantation rejection prevention. Subsequently, new generations of anti-CD3 antibodies have entered clinical trials for a broader spectrum of therapeutic applications, including cancer and autoimmune diseases. Despite their extensive use, little is known about the exact mechanism of these molecules, except that they are able to activate T cells, inducing an overall immunoregulatory and tolerogenic behavior. To better understand the effects of anti-CD3 antibodies on human T cells, PBMCs were stimulated, and then, we performed RNA-seq assays of enriched T cells to assess changes in their gene expression profiles. In this study, three different anti-CD3 antibodies were used for the stimulation: two recombinant antibody fragments, namely, a humanized and a chimeric FvFc molecule, and the prototype mouse mAb OKT3.

Results

Gene Ontology categories and individual immunoregulatory markers were compared, suggesting a similarity in modulated gene sets, mainly those for immunoregulatory and inflammatory terms. Upregulation of interleukin receptors, such as IL2RA, IL1R, IL12RB2, IL18R1, IL21R and IL23R, and of inhibitory molecules, such as FOXP3, CTLA4, TNFRSF18, LAG3 and PDCD1, were also observed, suggesting an inhibitory and exhausted phenotype.

Conclusions

We used a deep transcriptome sequencing method for comparing three anti-CD3 antibodies in terms of Gene Ontology enrichment and immunological marker expression. The present data showed that both recombinant antibodies induced a compatible expression profile, suggesting that they might be candidates for a closer evaluation with respect to their therapeutic value. Moreover, the proposed methodology is amenable to be more generally applied for molecular comparison of cell receptor dependent antibody therapy.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5967-8) contains supplementary material, which is available to authorized users.

High Thymic Output of Effector CD4+ Cells May Lead to a Treg : T Effector Imbalance in the Periphery in NOD Mice

Regulatory T cells (Tregs) play a critical role in controlling autoreactive T cells, and quantitative and/or qualitative deficiencies in Tregs are associated with autoimmune diseases, including type 1 diabetes (T1D), in both humans and mice. Both the incidence of T1D and percentages of peripheral Tregs in NOD mice vary considerably between animal facilities. In our animal facility, the incidence of T1D in NOD mice is high at 90-100% and the percentages of peripheral CD4⁺Foxp3⁺ cells in ~9-10-week-old female NOD mice are decreased compared to control (B6) mice shortly before high glucose is first detected (~12 weeks). These data suggest that there is an imbalance between Tregs and potentially pathogenic effector T cells at this age that could have significant impact on disease progression to overt diabetes. The goal of the current study was to investigate mechanisms that play a role in peripheral Treg : T effector cell balance in NOD mice, including differences in persistence/survival, peripheral homeostatic proliferation, and thymic production and output of CD4⁺ T cells. We found no differences in persistence/survival or homeostatic proliferation of either Tregs or effector T cells between NOD and B6 mice. Furthermore, although the percentages and absolute numbers of CD4⁺Foxp3⁺ cells in thymus were not decreased in NOD compared to B6 mice, the percentage of CD4⁺ recent thymic emigrants (RTE) that were Foxp3⁺ was significantly lower in 9-week-old NOD mice. Interestingly, the thymic output of CD4⁺Foxp3⁺ cells was not lower in NOD mice, whereas the thymic output of CD4⁺Foxp3⁻ cells was significantly higher in NOD mice at that age compared to B6 mice. These data suggest that the higher thymic output of CD4⁺Foxp3⁻ T cells contributes, at least in part, to the lower percentages of peripheral CD4⁺Foxp3⁺ Tregs in NOD mice and an imbalance between Tregs and T effector cells that may contribute to the development of full-blown diabetes.

In vivo imaging of type 1 diabetes immunopathology using eye-transplanted islets in NOD mice

AIMS/HYPOTHESIS

Autoimmune attack against the insulin-producing beta cells in the pancreatic islets results in type 1 diabetes. However, despite considerable research, details of the type 1 diabetes immunopathology in situ are not fully understood mainly because of difficult access to the pancreatic islets in vivo.

METHODS

Here, we used direct non-invasive confocal imaging of islets transplanted in the anterior chamber of the eye (ACE) to investigate the anti-islet autoimmunity in NOD mice before, during and after diabetes onset. ACE-transplanted islets allowed longitudinal studies of the autoimmune attack against islets and revealed the infiltration kinetics and in situ motility dynamics of fluorescence-labelled autoreactive T cells during diabetes development. Ex vivo immunostaining was also used to compare immune cell infiltrations into islet grafts in the eye and kidney as well as in pancreatic islets of the same diabetic NOD mice.

RESULTS

We found similar immune infiltration in native pancreatic and ACE-transplanted islets, which established the ACE-transplanted islets as reliable reporters of the autoimmune response. Longitudinal studies in ACE-transplanted islets identified in vivo hallmarks of islet inflammation that concurred with early immune infiltration of the islets and preceded their collapse and hyperglycaemia onset. A model incorporating data on ACE-transplanted islet degranulation and swelling allowed early prediction of the autoimmune attack in the pancreas and prompted treatments to intercept type 1 diabetes.

CONCLUSIONS/INTERPRETATION

The current findings highlight the value of ACE-transplanted islets in studying early type 1 diabetes pathogenesis in vivo and underscore the need for timely intervention to halt disease progression.

Immunotherapy with oral administration of humanized anti-CD3 monoclonal antibody: a novel gut-immune system-based therapy for metaflammation and NASH

The immune system plays a role in the pathogenesis of non-alcoholic steatohepatitis (NASH) underlying hepatocyte injury and fibrosis progression at all disease stages. Oral administration of anti-CD3 monoclonal antibody (mAb) has been shown in preclinical studies to be an effective method for systemic immune modulation and alleviates immune-mediated disorders without T cell depletion. In the present review, we summarize the concept of the oral administration of humanized anti-CD3 mAb in patients with NASH and discuss the potential of this treatment to address the current requirements of treatments for NASH. Recently published preclinical and clinical data on oral administration of anti CD3 are discussed. Human trials have shown that the oral administration of anti-CD3 in healthy volunteers, patients with chronic hepatitis C virus (HCV) infection and patients with NASH and type 2 diabetes is safe and well tolerated, as well as biologically active. Oral anti-CD3 induces regulatory T cells, suppresses the chronic inflammatory state associated with NASH and exerts a beneficial effect on clinically relevant parameters. Foralumab is a fully human anti-CD3 mAb that has recently been shown to exert a potent anti-inflammatory effect in humanized mice. It is being developed for treatment of NASH and primary biliary cholangitis (PBC). Oral administration of anti CD3 may provide an effective therapy for patients with NASH.

Regulatory T cells engineered with a novel insulin-specific chimeric antigen receptor as a candidate immunotherapy for type 1 diabetes

Adoptive immunotherapy with ex vivo expanded, polyspecific regulatory T cells (Tregs) is a promising treatment for graft-versus-host disease. Animal transplantation models used by us and others have demonstrated that the adoptive transfer of allospecific Tregs offers greater protection from graft rejection than that of polyclonal Tregs. This finding is in contrast to those of autoimmune models, where adoptive transfer of polyspecific Tregs had very limited effects, while antigen-specific Tregs were promising. However, antigen-specific Tregs in autoimmunity cannot be isolated in sufficient numbers. Chimeric antigen receptors (CARs) can modify T cells and redirect their specificity toward needed antigens and are currently clinically used in leukemia patients. A major benefit of CAR technology is its "off-the-shelf" usability in a translational setting in contrast to major histocompatibility complex (MHC)-restricted T cell receptors. We used CAR technology to redirect T cell specificity toward insulin and redirect T effector cells (Teffs) to Tregs by Foxp3 transduction. Our data demonstrate that our converted, insulin-specific CAR Tregs (cTregs) were functional stable, suppressive and long-lived in vivo. This is a proof of concept for both redirection of T cell specificity and conversion of Teffs to cTregs.

Low-Dose Anti-Thymocyte Globulin Preserves C-Peptide, Reduces HbA1c, and Increases Regulatory to Conventional T-Cell Ratios in New-Onset Type 1 Diabetes: Two-Year Clinical Trial Data

A three-arm, randomized, double-masked, placebo-controlled phase 2b trial performed by the Type 1 Diabetes TrialNet Study Group previously demonstrated that low-dose anti-thymocyte globulin (ATG) (2.5 mg/kg) preserved β-cell function and reduced HbA_1c for 1 year in new-onset type 1 diabetes. Subjects (N = 89) were randomized to 1) ATG and pegylated granulocyte colony-stimulating factor (GCSF), 2) ATG alone, or 3) placebo. Herein, we report 2-year area under the curve (AUC) C-peptide and HbA_1c, prespecified secondary end points, and potential immunologic correlates. The 2-year mean mixed-meal tolerance test-stimulated AUC C-peptide, analyzed by ANCOVA adjusting for baseline C-peptide, age, and sex (n = 82) with significance defined as one-sided P < 0.025, was significantly higher in subjects treated with ATG versus placebo (P = 0.00005) but not ATG/GCSF versus placebo (P = 0.032). HbA_1c was significantly reduced at 2 years in subjects treated with ATG (P = 0.011) and ATG/GCSF (P = 0.022) versus placebo. Flow cytometry analyses demonstrated reduced circulating CD4:CD8 ratio, increased regulatory T-cell:conventional CD4 T-cell ratios, and increased PD-1⁺CD4⁺ T cells following low-dose ATG and ATG/GCSF. Low-dose ATG partially preserved β-cell function and reduced HbA_1c 2 years after therapy in new-onset type 1 diabetes. Future studies should determine whether low-dose ATG might prevent or delay the onset of type 1 diabetes.

The Role of Inflammation in Diabetes: Current Concepts and Future Perspectives

Diabetes is a complex metabolic disorder affecting the glucose status of the human body. Chronic hyperglycaemia related to diabetes is associated with end organ failure. The clinical relationship between diabetes and atherosclerotic cardiovascular disease is well established. This makes therapeutic approaches that simultaneously target diabetes and atherosclerotic disease an attractive area for research. The majority of people with diabetes fall into two broad pathogenetic categories, type 1 or type 2 diabetes. The role of obesity, adipose tissue, gut microbiota and pancreatic beta cell function in diabetes are under intensive scrutiny with several clinical trials to have been completed while more are in development. The emerging role of inflammation in both type 1 and type 2 diabetes (T1D and T1D) pathophysiology and associated metabolic disorders, has generated increasing interest in targeting inflammation to improve prevention and control of the disease. After an extensive review of the possible mechanisms that drive the metabolic pattern in T1D and T2D and the inflammatory pathways that are involved, it becomes ever clearer that future research should focus on a model of combined suppression for various inflammatory response pathways.

Targeting Type 1 Diabetes: Selective Approaches for New Therapies

The clinical onset of type 1 diabetes is characterized by the destruction of the insulin-producing β cells of the pancreas and is caused by autoantigen-induced inflammation (insulitis) of the islets of Langerhans. The current standard of care for type 1 diabetes mellitus patients allows for management of the disease with exogenous insulin, but patients eventually succumb to many chronic complications such as limb amputation, blindness, and kidney failure. New therapeutic approaches now on the horizon are looking beyond glycemic management and are evaluating new strategies from protecting and regenerating endogenous islets to treating the underlying autoimmunity through selective modulation of key immune cell populations. Currently, there are no effective treatments for the autoimmunity that causes the disease, and strategies that aim to delay or prevent the onset of the disease will play an important role in the future of diabetes research. In this review, we summarize many of the key efforts underway that utilize molecular approaches to selectively modulate this disease and look at new therapeutic paradigms that can transform clinical treatment.

The challenge of modulating β-cell autoimmunity in type 1 diabetes

With the conceptual advance about four decades ago that type 1 diabetes represents an autoimmune disease, hope arose that immune-based therapies would soon emerge to prevent and reverse the disorder. However, despite dozens of clinical trials seeking to achieve these goals, the promise remains unfulfilled, at least in a pragmatic form. With the benefit of hindsight, several important reasons are likely to account for this disappointing outcome, including failure to appreciate disease heterogeneity, inappropriate use of rodent models of disease, inadequacies in addressing the immunological and metabolic contributions to the disease, suboptimal trial designs, and lack of a clear understanding of the pathogenesis of type 1 diabetes. In this Series paper, we convey how recent knowledge gains in these areas, combined with efforts related to disease staging and emerging mechanistic data from clinical trials, provide cautious optimism that immune-based approaches to prevent the loss of β cells in type 1 diabetes will emerge into clinical practice.

CD19+IgM+ cells demonstrate enhanced therapeutic efficacy in type 1 diabetes mellitus

We describe a protective effect on autoimmune diabetes and reduced destructive insulitis in NOD.scid recipients following splenocyte injections from diabetic NOD donors and sorted CD19+ cells compared with NOD.scid recipients receiving splenocytes alone. This protective effect was age specific (only CD19+ cells from young NOD donors exerted this effect; P < 0.001). We found that the CD19+IgM+ cell is the primary subpopulation of B cells that delayed transfer of diabetes mediated by diabetogenic T cells from NOD mice (P = 0.002). Removal of IgM+ cells from the CD19+ pool did not result in protection. Notably, protection conferred by CD19+IgM+ cotransfers were not dependent on the presence of Tregs, as their depletion did not affect their ability to delay onset of diabetes. Blockade of IL-10 with neutralizing antibodies at the time of CD19+ cell cotransfers also abrogated the therapeutic effect, suggesting that IL-10 secretion was an important component of protection. These results were strengthened by ex vivo incubation of CD19+ cells with IL-5, resulting in enhanced proliferation and IL-10 production and equivalently delayed diabetes progression (P = 0.0005). The potential to expand CD19+IgM+ cells, especially in response to IL-5 stimulation or by pharmacologic agents, may be a new therapeutic option for type 1 diabetes.

Factors affecting Salmonella-based combination immunotherapy for prevention of type 1 diabetes in non-obese diabetic mice

We previously reported the development of an oral vaccine for diabetes based on live attenuated Salmonella-expressing preproinsulin (PPI) as the autoantigen. When combined with host cell-expressed TGFβ, the vaccine prevented the onset of diabetes in non-obese diabetic (NOD) mice. Herein, we investigated factors that could affect vaccine efficacy including vaccination number, optimization of the autoantigen codon sequence, Salmonella SPI2-TTSS promoter/effector combinations, concurrent short-course low-dose anti-CD3. We also evaluated autoantigen GAD65 and cytokine IL10 treatment upon vaccine efficacy. T-cells we employed to elucidate the mechanism of the vaccine action. Our results showed that GAD65+TGFβ or PPI+TGFβ+IL10 prevented the onset of diabetes in the NOD mice and maintained glucose tolerance. However, increasing the number of vaccine doses, codon-optimization of the autoantigen(s) or use of other Salmonella promoter/effector combinations had no in vivo effect. Interestingly, two doses of vaccine (PPI+TGFβ+IL10) combined with a sub-therapeutic dose of anti-CD3 prevented diabetes and decreased hyperglycemia in mice. The combined therapy also increased splenic Tregs and local Tregs in pancreatic lymph nodes (PLN) and increased regulatory (IL10 and IL2) but reduced inflammatory (IFNγ and TNFα) cytokines. Together, these results indicate that the combination of low vaccine dose number, less vaccine autoantigen expression and short-course low-dose anti-CD3 can increase regulatory mechanisms and suppress autoimmunity.

Therapeutic tolerance in autoimmune disease

Experimental immune tolerance induction, enabling tissues to be transplanted across animal strains, was first demonstrated in the 1950s. Therapeutic tolerance induction, whereby immune tolerance is used to treat or prevent transplant rejection, and as a treatment for autoimmunity, followed in the 1980s. Clinical translation has been slow but the pace of change is accelerating. Numerous strategies are now being tested clinically, ranging from monoclonal antibodies against T-cells, to peptide therapies, cellular therapies and microbiome manipulation. Furthermore, technology has advanced to the stage where we can start to monitor serological and cellular autoreactivity as biomarkers of response. In terms of autoimmunity, recognition of the prolonged phase of preclinical autoimmunity in several conditions, is leading to debate around treatment of at risk individuals, and trials in patients with prodromal clinical symptoms, such as seropositive arthralgia. Additionally, potent immunomodulatory drugs are achieving a substantial track record of safety. Putting these various factors together suggests that we can soon expect to see more trials of tolerogenic strategies in pre-clinical disease, with intensive immune monitoring to guide therapy.

Therapies to Suppress β Cell Autoimmunity in Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease that is generally considered to be T cell-driven. Accordingly, most strategies of immunotherapy for T1D prevention and treatment in the clinic have targeted the T cell compartment. To date, however, immunotherapy has had only limited clinical success. Although certain immunotherapies have promoted a protective effect, efficacy is often short-term and acquired immunity may be impacted. This has led to the consideration of combining different approaches with the goal of achieving a synergistic therapeutic response. In this review, we will discuss the status of various T1D therapeutic strategies tested in the clinic, as well as possible combinatorial approaches to restore β cell tolerance.

Molecular Mechanisms of T Cells Activation by Dendritic Cells in Autoimmune Diseases

The interaction between T cell and dendritic cells (DCs) that leads to T cell activation affects the progression of the immune response including autoimmune diseases. Antigen presentation on immune cell surface, formation of an immunological synapse (IS), and specific identification of complex by T cells including two activating signals are necessary steps that lead to T cell activation. The formation of stimulatory IS involves the inclusion of costimulatory molecules, such as ICAM-1/LFA-1 and CD28/B7-1, and so on. Some fusion proteins and monoclonal antibodies targeting costimulatory molecules have been developed and approved to treat autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), type I diabetes (T1D), inflammatory bowel disease (IBD), and psoriasis. These biological agents, including CTLA-4- and LFA-3-Ig, anti-CD3 monoclonal antibody, could prevent the successful engagement of DCs by T cell with significant efficacy and safety profile. In this article, we reviewed the molecular mechanisms of T cell activation during the interaction between T cells and DCs, and summarized some biological agents that target costimulatory molecules involved in the regulation of T cell activation.

Monitoring T-Cell Responses in Translational Studies: Optimization of Dye-Based Proliferation Assay for Evaluation of Antigen-Specific Responses

Adoptive therapy with regulatory T cells or tolerance-inducing antigen (Ag)-presenting cells is innovative and promising therapeutic approach to control undesired and harmful activation of the immune system, as observed in autoimmune diseases, solid organ and bone marrow transplantation. One of the critical issues to elucidate the mechanisms responsible for success or failure of these therapies and define the specificity of the therapy is the evaluation of the Ag-specific T-cell responses. Several efforts have been made to develop suitable and reproducible assays. Here, we focus on dye-based proliferation assays. We highlight with practical examples the fundamental issues to take into consideration for implementation of an effective and sensitive dye-based proliferation assay to monitor Ag-specific responses in patients. The most critical points were used to design a road map to set up and analyze the optimal assay to assess Ag-specific T-cell responses in patients undergoing different treatments. This is the first step to optimize monitoring of tolerance induction, allowing comparison of outcomes of different clinical studies. The road map can also be applied to other therapeutic interventions, not limited to tolerance induction therapies, in which Ag-specific T-cell responses are relevant such as vaccination approaches and cancer immunotherapy.

Avidity and Bystander Suppressive Capacity of Human Regulatory T Cells Expressing De Novo Autoreactive T-Cell Receptors in Type 1 Diabetes

The ability to alter antigen specificity by T-cell receptor (TCR) or chimeric antigen receptor (CAR) gene transfer has facilitated personalized cellular immune therapies in cancer. Inversely, this approach can be harnessed in autoimmune settings to attenuate inflammation by redirecting the specificity of regulatory T cells (Tregs). Herein, we demonstrate efficient protocols for lentiviral gene transfer of TCRs that recognize type 1 diabetes-related autoantigens with the goal of tissue-targeted induction of antigen-specific tolerance to halt β-cell destruction. We generated human Tregs expressing a high-affinity GAD_555–567-reactive TCR (clone R164), as well as the lower affinity clone 4.13 specific for the same peptide. We demonstrated that de novo Treg avatars potently suppress antigen-specific and bystander responder T-cell (Tresp) proliferation in vitro in a process that requires Treg activation (P < 0.001 versus unactivated Tregs). When Tresp were also glutamic acid decarboxylase (GAD)-reactive, the high-affinity R164 Tregs exhibited increased suppression (P < 0.01) with lower Tresp-division index (P < 0.01) than the lower affinity 4.13 Tregs. These data demonstrate the feasibility of rapid expansion of antigen-specific Tregs for applications in attenuating β-cell autoimmunity and emphasize further opportunities for engineering cellular specificities, affinities, and phenotypes to tailor Treg activity in adoptive cell therapies for the treatment of type 1 diabetes.

T Cell Receptor Profiling in Type 1 Diabetes

PURPOSE OF REVIEW

The genetic susceptibility and dominant protection for type 1 diabetes (T1D) associated with human leukocyte antigen (HLA) haplotypes, along with minor risk variants, have long been thought to shape the T cell receptor (TCR) repertoire and eventual phenotype of autoreactive T cells that mediate β-cell destruction. While autoantibodies provide robust markers of disease progression, early studies tracking autoreactive T cells largely failed to achieve clinical utility.

RECENT FINDINGS

Advances in acquisition of pancreata and islets from T1D organ donors have facilitated studies of T cells isolated from the target tissues. Immunosequencing of TCR α/β-chain complementarity determining regions, along with transcriptional profiling, offers the potential to transform biomarker discovery. Herein, we review recent studies characterizing the autoreactive TCR signature in T1D, emerging technologies, and the challenges and opportunities associated with tracking TCR molecular profiles during the natural history of T1D.

Are Regulatory T Cells Defective in Type 1 Diabetes and Can We Fix Them?

Regulatory T cells (Tregs) are critical regulators of peripheral immune tolerance. Treg insufficiency can lead to autoimmune disorders, including type 1 diabetes (T1D). Increasing evidence in mouse models of T1D, as well as other autoimmune disorders, suggests that there are defects in Treg-mediated suppression. Indeed, whereas Treg frequency in the peripheral blood of T1D patients is unaltered, their suppressive abilities are diminished compared with Tregs in healthy controls. Although expression of the transcription factor Foxp3 is a prerequisite for Treg development and function, there are many additional factors that can alter their stability, survival, and function. Much has been learned in other model systems, such as tumors, about the mechanism and pathways that control Treg stability and function. This review poses the question of whether we can use these findings to develop new therapeutic approaches that might boost Treg stability, survival, and/or function in T1D and possibly other autoimmune disorders.

Oral treatment with foralumab, a fully human anti-CD3 monoclonal antibody, prevents skin xenograft rejection in humanized mice

Oral administration of biologics may be a feasible approach for immune therapy that improves drug safety and potentiates mechanisms of tolerance at mucosal barriers. We tested the ability of a fully human non-FcR binding anti-CD3 mAb, foralumab, to prevent skin xenograft rejection in mice with human immune systems. At an intragastric dose of 15μg, the drug could transit through the small bowel. Serum absorption and binding of lymphoid cells was seen and proliferative responses of splenic CD8+ T cells to mitogen were reduced. Five consecutive daily doses, then weekly dosing led to indefinite graft acceptance without depletion of peripheral T cells. Proliferative and cytokine responses to activation of splenocytes with PHA were reduced. The serum levels of IL-10 but not TNF were increased 6days after application of the skin graft. Oral treatment with anti-CD3 mAb may represent a feasible approach for immune modulation.

Use of short interfering RNA delivered by cationic liposomes to enable efficient down-regulation of PTPN22 gene in human T lymphocytes

Type 1 diabetes and thyroid disease are T cell-dependent autoimmune endocrinopathies. The standard substitutive administration of the deficient hormones does not halt the autoimmune process; therefore, development of immunotherapies aiming to preserve the residual hormonal cells, is of crucial importance. PTPN22 C1858T mutation encoding for the R620W lymphoid tyrosine phosphatase variant, plays a potential pathophysiological role in autoimmunity. The PTPN22 encoded protein Lyp is a negative regulator of T cell antigen receptor signaling; R620W variant, leading to a gain of function with paradoxical reduced T cell activation, may represent a valid therapeutic target. We aimed to develop novel wild type PTPN22 short interfering RNA duplexes (siRNA) and optimize their delivery into Jurkat T cells and PBMC by using liposomal carriers. Conformational stability, size and polydispersion of siRNA in lipoplexes was measured by CD spectroscopy and DLS. Lipoplexes internalization and toxicity evaluation was assessed by confocal microscopy and flow cytometry analysis. Their effect on Lyp expression was evaluated by means of Western Blot and confocal microscopy. Functional assays through engagement of TCR signaling were established to evaluate biological consequences of down-modulation. Both Jurkat T cells and PBMC were efficiently transfected by stable custom lipoplexes. Jurkat T cell morphology and proliferation was not affected. Lipoplexes incorporation was visualized in CD3+ but also in CD3- peripheral blood immunotypes without signs of toxicity, damage or apoptosis. Efficacy in affecting Lyp protein expression was demonstrated in both transfected Jurkat T cells and PBMC. Moreover, impairment of Lyp inhibitory activity was revealed by increase of IL-2 secretion in culture supernatants of PBMC following anti-CD3/CD28 T cell receptor-driven stimulation. The results of our study open the pathway to future trials for the treatment of autoimmune diseases based on the selective inhibition of variant PTPN22 allele using lipoplexes of siRNA antisense oligomers.

The Proteasome Inhibitor Bortezomib Controls Indoleamine 2,3-Dioxygenase 1 Breakdown and Restores Immune Regulation in Autoimmune Diabetes

Bortezomib (BTZ) is a first-in-class proteasome inhibitor approved for the therapy of multiple myeloma that also displays unique regulatory activities on immune cells. The enzyme indoleamine 2,3-dioxygenase 1 (IDO1) is a tryptophan metabolizing enzyme exerting potent immunoregulatory effects when expressed in dendritic cells (DCs), the most potent antigen-presenting cells capable of promoting either immunity or tolerance. We previously demonstrated that, in inflammatory conditions, IDO1 is subjected to proteasomal degradation in DCs, turning these cells from immunoregulatory to immunostimulatory. In non-obese diabetic (NOD) mice, an experimental model of autoimmune diabetes, we also identified an IDO1 defect such that the DCs do not develop tolerance toward pancreatic islet autoantigens. We found that BTZ rescues IDO1 protein expression in vitro in a particular subset of DCs, i.e., plasmacytoid DCs (pDCs) from NOD mice. When administered in vivo to prediabetic mice, the drug prevented diabetes onset through IDO1- and pDC-dependent mechanisms. Although the drug showed no therapeutic activity when administered alone to overtly diabetic mice, its combination with otherwise suboptimal dosages of autoimmune-preventive anti-CD3 antibody resulted in disease reversal in 70% diabetic mice, a therapeutic effect similar to that afforded by full-dosage anti-CD3. Thus, our data indicate a potential for BTZ in the immunotherapy of autoimmune diabetes and further underline the importance of IDO1-mediated immune regulation in such disease.

Advances in treatment of active, moderate-to-severe Graves' ophthalmopathy

Graves' ophthalmopathy is defined as autoimmune inflammation of extraocular muscles and orbital fat or connective tissue, usually in patients with Graves' disease. About one in 20 patients with Graves' hyperthyroidism has moderate-to-severe Graves' ophthalmopathy. Corticosteroids have been the mainstay of treatment, but new evidence about immune mechanisms has provided a basis to explore other drug classes. Intravenous methylprednisolone pulses are more effective and better tolerated than oral prednisone in the treatment of active, moderate-to-severe Graves' ophthalmopathy. Rituximab has also been suggested as a possible replacement for intravenous corticosteroids. Two randomised controlled trials of rituximab reached seemingly contradictory conclusions-rituximab was not better with respect to the primary outcome (clinical activity score) than placebo in one trial (which, however, was confounded by rather long Graves' ophthalmopathy duration), but was slightly better than intravenous methylprednisolone pulses in the other (disease flare-ups occurred only in the latter group). On the basis of evidence published so far, rituximab cannot replace intravenous methylprednisolone pulses, but could have a role in corticosteroid-resistant cases. Open-label studies of tumour-necrosis-factor-α blockade had limited efficacy, but other studies showed that interleukin-6 receptor antibodies were effective. Results of randomised controlled trials investigating the efficacy of the IGF-1 receptor antibody teprotumumab and the interleukin-6 receptor antibody tocilizumab are expected shortly. Approaches that target the causal mechanism of Graves' ophthalmopathy (antibodies or antagonists that block thyroid-stimulating-hormone receptors) also look promising.

Isogenic Cellular Systems Model the Impact of Genetic Risk Variants in the Pathogenesis of Type 1 Diabetes

At least 57 independent loci within the human genome confer varying degrees of risk for the development of type 1 diabetes (T1D). The majority of these variants are thought to contribute to overall genetic risk by modulating host innate and adaptive immune responses, ultimately resulting in a loss of immunological tolerance to β cell antigens. Early efforts to link specific risk variants with functional alterations in host immune responses have employed animal models or genotype-selected individuals from clinical bioresource banks. While some notable genotype:phenotype associations have been described, there remains an urgent need to accelerate the discovery of causal variants and elucidate the molecular mechanisms by which susceptible alleles alter immune functions. One significant limitation has been the inability to study human T1D risk loci on an isogenic background. The advent of induced pluripotent stem cells (iPSCs) and genome-editing technologies have made it possible to address a number of these outstanding questions. Specifically, the ability to drive multiple cell fates from iPSC under isogenic conditions now facilitates the analysis of causal variants in multiple cellular lineages. Bioinformatic analyses have revealed that T1D risk genes cluster within a limited number of immune signaling pathways, yet the relevant immune cell subsets and cellular activation states in which candidate risk genes impact cellular activities remain largely unknown. In this review, we summarize the functional impact of several candidate risk variants on host immunity in T1D and present an isogenic disease-in-a-dish model system for interrogating risk variants, with the goal of expediting precision therapeutics in T1D.

Mucosal administration of CD3-specific monoclonal antibody inhibits diabetes in NOD mice and in a preclinical mouse model transgenic for the CD3 epsilon chain

CD3-specific monoclonal antibody (mAb) treats autoimmune disease in animal models and has shown promise in clinical trials of type 1 diabetes. Whereas intravenous administration of CD3-specific mAb acts primarily by transient depletion of activated effector T cells, oral CD3-specific mAb acts primarily by the induction Tregs. We investigated whether oral CD3-specific mAb inhibits disease in non obese diabetic (NOD) mice that spontaneously develop autoimmune diabetes, closely resembling human type 1 diabetes. We found that oral CD3-specific mAb treatment delayed onset and reduced incidence of diabetes in NOD mice, inducing changes in both effector and regulatory T cell compartments. The therapeutic effect was associated with decreased T cell proliferation, decreased IFNγ and IL-17 production, and increased TGF-β and IL-10 production in vitro. In vivo transfer experiments demonstrated that oral CD3-specific mAb decreased diabetogenicity of effector T cells and increased the function of regulatory T cells. Oral OKT3, a monoclonal antibody specific for human CD3 had equivalent effects in transgenic NOD mice expressing the human CD3 epsilon chain which serves as a preclinical model for testing human CD3-specific mAb. These results suggest that oral CD3-specific mAb has the potential for treating autoimmune diabetes in humans.

IL-10-dependent Tr1 cells attenuate astrocyte activation and ameliorate chronic central nervous system inflammation

See Winger and Zamvil (doi: 10.1093/brain/aww121 ) for a scientific commentary on this article.

The innate immune system plays a central role in the chronic central nervous system inflammation that drives neurological disability in progressive forms of multiple sclerosis, for which there are no effective treatments. The mucosal immune system is a unique tolerogenic organ that provides a physiological approach for the induction of regulatory T cells. Here we report that nasal administration of CD3-specific antibody ameliorates disease in a progressive animal model of multiple sclerosis. This effect is IL-10-dependent and is mediated by the induction of regulatory T cells that share a similar transcriptional profile to Tr1 regulatory cells and that suppress the astrocyte inflammatory transcriptional program. Treatment results in an attenuated inflammatory milieu in the central nervous system, decreased microglia activation, reduced recruitment of peripheral monocytes, stabilization of the blood–brain barrier and less neurodegeneration. These findings suggest a new therapeutic approach for the treatment of progressive forms of multiple sclerosis and potentially other types of chronic central nervous system inflammation.

Obstacles and opportunities for targeting the effector T cell response in type 1 diabetes

Autoreactive lymphocytes display a programmed set of characteristic effector functions and phenotypic markers that, in combination with antigen-specific profiling, provide a detailed picture of the adaptive immune response in Type 1 diabetes (T1D). The CD4+ T cell effector compartment (referred to as "Teff" in this article) has been extensively analyzed, particularly because the HLA genes most strongly associated with T1D are MHC class II alleles that form restriction elements for CD4+ T cell recognition. This "guilt by association" can now be revisited in terms of specific immune mechanisms and specific forms of T cell recognition that are displayed by Teff found in subjects with T1D. In this review, we describe properties of Teff that correlate with T1D, and discuss several characteristics that advance our understanding of disease persistence and progression. Focusing on functional disease-associated immunological pathways within these Teff suggests a rationale for next-generation clinical trials with targeted interventions. Indeed, immune modulation therapies in T1D that do not address these properties of Teff are unlikely to achieve durable clinical response.

Inducing and Administering Tregs to Treat Human Disease

Regulatory T cells (Tregs) control unwanted immune responses, including those that mediate tolerance to self as well as to foreign antigens. Their mechanisms of action include direct and indirect effects on effector T cells and important functions in tissue repair and homeostasis. Tregs express a number of cell surface markers and transcriptional factors that have been instrumental in defining their origins and potentially their function. A number of immune therapies, such as rapamycin, IL-2, and anti-T cell antibodies, are able to induce Tregs and are being tested for their efficacy in diverse clinical settings with exciting preliminary results. However, a balance exists with the use of some, such as IL-2, that may have effects on unwanted populations as well as promoting expansion and survival of Tregs requiring careful selection of dose for clinical use. The use of cell surface markers has enabled investigators to isolate and expand ex vivo Tregs more than 500-fold routinely. Clinical trials have begun, administering these expanded Tregs to patients as a means of suppressing autoimmune and alloimmune responses and potentially inducing immune tolerance. Studies in the future are likely to build on these initial technical achievements and use combinations of agents to improve the survival and functional capacity of Tregs.

Th17 cytokines differentiate obesity from obesity-associated type 2 diabetes and promote TNFα production

OBJECTIVE

T cell inflammation plays pivotal roles in obesity-associated type 2 diabetes (T2DM). The identification of dominant sources of T cell inflammation in humans remains a significant gap in understanding disease pathogenesis. It was hypothesized that cytokine profiles from circulating T cells identify T cell subsets and T cell cytokines that define T2DM-associated inflammation.

METHODS

Multiplex analyses were used to quantify T cell-associated cytokines in αCD3/αCD28-stimulated PBMCs, or B cell-depleted PBMCs, from subjects with T2DM or BMI-matched controls. Cytokine measurements were subjected to multivariate (principal component and partial least squares) analyses. Flow cytometry detected intracellular TNFα in multiple immune cell subsets in the presence/absence of antibodies that neutralize T cell cytokines.

RESULTS

T cell cytokines were generally higher in T2DM samples, but Th17 cytokines are specifically important for classifying individuals correctly as T2DM. Multivariate analyses indicated that B cells support Th17 inflammation in T2DM but not control samples, while monocytes supported Th17 inflammation regardless of T2DM status. Partial least squares regression analysis indicated that both Th17 and Th1 cytokines impact %HbA1c.

CONCLUSIONS

Among various T cell subsets, Th17 cells are major contributors to inflammation and hyperglycemia and are uniquely supported by B cells in obesity-associated T2DM.

Anti-CD3/Anti-CXCL10 Antibody Combination Therapy Induces a Persistent Remission of Type 1 Diabetes in Two Mouse Models

Anti-CD3 therapy of type 1 diabetes results in a temporary halt of its pathogenesis but does not constitute a permanent cure. One problem is the reinfiltration of islets of Langerhans with regenerated, autoaggressive lymphocytes. We aimed at blocking such a reentry by neutralizing the key chemokine CXCL10. Combination therapy of diabetic RIP-LCMV and NOD mice with anti-CD3 and anti-CXCL10 antibodies caused a substantial remission of diabetes and was superior to monotherapy with anti-CD3 or anti-CXCL10 alone. The combination therapy prevented islet-specific T cells from reentering the islets of Langerhans and thereby blocked the autodestructive process. In addition, the local immune balance in the pancreas was shifted toward a regulatory phenotype. A sequential temporal inactivation of T cells and blockade of T-cell migration might constitute a novel therapy for patients with type 1 diabetes.

Targeting memory T cells in type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease that leads to progressive destruction of pancreatic beta cells. Compared to healthy controls, a characteristic feature of patients with T1D is the presence of self-reactive T cells with a memory phenotype. These autoreactive memory T cells in both the CD4(+) and CD8(+) compartments are likely to be long-lived, strongly responsive to antigenic stimulation with less dependence on costimulation for activation and clonal expansion, and comparatively resistant to suppression by regulatory T cells (Tregs) or downregulation by immune-modulating agents. Persistence of autoreactive memory T cells likely contributes to the difficulty in preventing disease progression in new-onset T1D and maintaining allogeneic islet transplants by regular immunosuppressive regimens. The majority of immune interventions that have demonstrated some success in preserving beta cell function in the new-onset period have been shown to deplete or modulate memory T cells. Based on these and other considerations, preservation of residual beta cells early after diagnosis or restoration of beta cell mass by use of stem cell or transplantation technology will require a successful strategy to control the autoreactive memory T cell compartment, which could include depletion, inhibition of homeostatic cytokines, induction of hyporesponsiveness, or a combination of these approaches.