CD3-specific antibodies: a portal to the treatment of autoimmunity

Non-Invasive Multiphoton Imaging of Islets Transplanted Into the Pinna of the NOD Mouse Ear Reveals the Immediate Effect of Anti-CD3 Treatment in Autoimmune Diabetes

We present a novel and readily accessible method facilitating cellular time-resolved imaging of transplanted pancreatic islets. Grafting of islets to the mouse ear pinna allows non-invasive, in vivo longitudinal imaging of events in the islets and enables improved acquisition of experimental data and use of fewer experimental animals than is possible using invasive techniques, as the same mouse can be assessed for the presence of islet infiltrating cells before and after immune intervention. We have applied this method to investigating therapeutic protection of beta cells through the well-established use of anti-CD3 injection, and have acquired unprecedented data on the nature and rapidity of the effect on the islet infiltrating T cells. We demonstrate that infusion of anti-CD3 antibody leads to immediate effects on islet infiltrating T cells in islet grafts in the pinna of the ear, and causes them to increase their speed and displacement within 20 min of infusion. This technique overcomes several technical challenges associated with intravital imaging of pancreatic immune responses and facilitates routine study of beta islet cell development, differentiation, and function in health and disease.

PKM2-dependent metabolic reprogramming in CD4+ T cells is crucial for hyperhomocysteinemia-accelerated atherosclerosis

Inflammation mediated by activated T cells plays an important role in the initiation and progression of hyperhomocysteinemia (HHcy)-accelerated atherosclerosis in ApoE^-/- mice. Homocysteine (Hcy) activates T cells to secrete proinflammatory cytokines, especially interferon (IFN)-γ; however, the precise mechanisms remain unclear. Metabolic reprogramming is critical for T cell inflammatory activation and effector functions. Our previous study demonstrated that Hcy regulates T cell mitochondrial reprogramming by enhancing endoplasmic reticulum (ER)-mitochondria coupling. In this study, we further explored the important role of glycolysis-mediated metabolic reprogramming in Hcy-activated CD4⁺ T cells. Mechanistically, Hcy-activated CD4⁺ T cell increased the protein expression and activity of pyruvate kinase muscle isozyme 2 (PKM2), the final rate-limiting enzyme in glycolysis, via the phosphatidylinositol 3-kinase/AKT/mechanistic target of rapamycin signaling pathway. Knockdown of PKM2 by small interfering RNA reduced Hcy-induced CD4⁺ T cell IFN-γ secretion. Furthermore, we generated T cell-specific PKM2 knockout mice by crossing LckCre transgenic mice with PKM2^fl/fl mice and observed that Hcy-induced glycolysis and oxidative phosphorylation were both diminished in PKM2-deficient CD4⁺ T cells with reduced glucose and lipid metabolites, and subsequently reduced IFN-γ secretion. T cell-depleted apolipoprotein E-deficient (ApoE^-/-) mice adoptively transferred with PKM2-deficient CD4⁺ T cells, compared to mice transferred with control cells, showed significantly decreased HHcy-accelerated early atherosclerotic lesion formation. In conclusion, this work indicates that the PKM2-dependent glycolytic-lipogenic axis, a novel mechanism of metabolic regulation, is crucial for HHcy-induced CD4⁺ T cell activation to accelerate early atherosclerosis in ApoE^-/- mice.

KEY MESSAGES

Metabolic reprogramming is crucial for Hcy-induced CD4⁺ T cell inflammatory activation. Hcy activates the glycolytic-lipogenic pathway in CD4⁺ T cells via PKM2. Targeting PKM2 attenuated HHcy-accelerated early atherosclerosis in ApoE^-/- mice in vivo.

Modulation of immune responses in lentiviral vector-mediated gene transfer

Lentiviral vectors (LV) are widely used vehicles for gene transfer and therapy in pre-clinical animal models and clinical trials with promising safety and efficacy results. However, host immune responses against vector- and/or transgene-derived antigens remain a major obstacle to the success and broad applicability of gene therapy. Here we review the innate and adaptive immunological barriers to successful gene therapy, both in the context of ex vivo and in vivo LV gene therapy, mostly concerning systemic LV delivery and discuss possible means to overcome them, including vector design and production and immune modulatory strategies.

Oral histone deacetylase inhibitor synergises with T cell targeted immunotherapy to preserve beta cell metabolic function and induce stable remission of new-onset autoimmune diabetes in NOD mice

AIM/HYPOTHESIS

Combination therapy targeting the major actors involved in the immune-mediated destruction of pancreatic beta cells appears to be an indispensable approach to treat type 1 diabetes effectively. We hypothesised that the combination of an orally active pan-histone deacetylase inhibitor (HDACi: givinostat) with subtherapeutic doses of CD3 antibodies may provide ideal synergy to treat ongoing autoimmunity.

METHODS

NOD mice transgenic for the human CD3ε (also known as CD3E) chain (NOD-huCD3ε) were treated for recent-onset diabetes with oral givinostat, subtherapeutic doses of humanised CD3 antibodies (otelixizumab, 50 μg/day, 5 days, i.v.) or a combination of both drugs. Disease remission, metabolic profiles and autoreactive T cell responses were analysed in treated mice.

RESULTS

We demonstrated that givinostat synergised with otelixizumab to induce durable remission of diabetes in 80% of recently diabetic NOD-huCD3ε mice. Remission was obtained in only 47% of mice treated with otelixizumab alone. Oral givinostat monotherapy did not reverse established diabetes but reduced the in situ production of inflammatory cytokines (IL-1β, IL-6, TNF-α). Importantly, the otelixizumab + givinostat combination strongly improved the metabolic status of NOD-huCD3ε mice; the mice recovered the capacity to appropriately produce insulin, control hyperglycaemia and sustain glucose tolerance. Finally, diabetes remission induced by the combination therapy was associated with a significant reduction of insulitis and autoantigen-specific CD8⁺ T cell responses.

CONCLUSIONS/INTERPRETATION

HDACi and low-dose CD3 antibodies synergised to abrogate in situ inflammation and thereby improved pancreatic beta cell survival and metabolic function leading to long-lasting diabetes remission. These results support the therapeutic potential of protocols combining these two drugs, both in clinical development, to restore self-tolerance and insulin independence in type 1 diabetes.

Construction of Human Immune and Naive scFv Libraries

Antibody phage display is the most commonly used in vitro selection technology for the generation of human recombinant antibodies and has yielded thousands of useful antibodies for research, diagnostics, and therapy. The prerequisite for successful generation of antibodies using phage display is the construction of high-quality antibody gene libraries. Here, we give the detailed methods for the construction of human immune and naive scFv gene libraries.

Revisiting the phenotypic and genetic profiling of anergic T cells mediating long-term transplant tolerance

PURPOSE OF REVIEW

Herein our focus will be to revisit peripheral tolerance mechanisms and in particular 'active' or 'dominant' tolerance as originally defined and mediated by regulatory CD4FoxP3 T lymphocytes (Treg) and also T-cell anergy that appears as a major mainstay to support long-term allograft survival.

RECENT FINDINGS

It is at the same time interesting and rewarding that the tool that recently guided our efforts along this path is the in-vivo use of CD3 antibody, the first monoclonal introduced in the clinic (Orthoclone OKT3) about 35 years ago to treat and prevent rejection of renal allografts. Beyond their immunosuppressive activity, whenever administered judiciously, CD3 antibodies promote robust allograft tolerance through selective purging of alloreactive effectors, resetting Treg-mediated active tolerance and promoting a unique subset of anergic CD8 T cells.

SUMMARY

The new findings discussed open up new perspectives from both a fundamental and a clinical point of view. In basic research, concrete molecular signaling paths are now spotted to finely dissect the conditions that lead to the establishment and maintenance of robust T-lymphocyte anergy mediating allograft tolerance. In the clinic, this may rapidly translate into novel biomarkers to be used in parallel to the ones already available, to better adapt posttransplant immunotherapy and monitor for long-term allograft acceptance.

Update on Dendritic Cell-Induced Immunological and Clinical Tolerance

Dendritic cells (DCs) as highly efficient antigen-presenting cells are at the interface of innate and adaptive immunity. As such, they are key mediators of immunity and antigen-specific immune tolerance. Due to their functional specialization, research efforts have focused on the characterization of DCs subsets involved in the initiation of immunogenic responses and in the maintenance of tissue homeostasis. Tolerogenic DCs (tolDCs)-based therapies have been designed as promising strategies to prevent and control autoimmune diseases as well as allograft rejection after solid organ transplantation (SOT). Despite successful experimental studies and ongoing phase I/II clinical trials using autologous tolDCs in patients with type 1 diabetes, rheumatoid arthritis, multiple sclerosis, and in SOT recipients, additional basic research will be required to determine the optimal DC subset(s) and conditioning regimens for tolDCs-based treatments in vivo. In this review, we discuss the characteristics of human DCs and recent advances in their classification, as well as the role of DCs in immune regulation and their susceptibility to in vitro or in vivo manipulation for the development of tolerogenic therapies, with a focus on the potential of tolDCs for the treatment of autoimmune diseases and the prevention of allograft rejection after SOT.

TH17 cells express ST2 and are controlled by the alarmin IL-33 in the small intestine

T_H17 cells are major drivers of inflammation and involved in several autoimmune diseases. Tissue inflammation is a beneficial host response to infection, but it can also contribute to autoimmunity. The crosstalk between a tissue and the immune system during an inflammatory response is key for preserving tissue integrity and restoring physiological processes. However, how the inflamed tissue regulates the magnitude of an immune response by controlling pro-inflammatory T cells is not well characterized so far. Here we show that T_H17 cells accumulating in the small intestine upon inflammation express the IL-33 receptor (ST2) and intestinal epithelial cells (IEC) are the main source of the alarmin interleukin-33 (IL-33). We show that pro-inflammatory T_H17 cells acquire a regulatory phenotype with immunosuppressive properties in response to IL-33. Absence of ST2 signaling promotes the secretion of pro-inflammatory cytokines by T_H17 cells and dampens the secretion of IL-10. Our results provide new insights into the mechanisms by which IEC, via IL-33/ST2 axis, may control pro-inflammatory T_H17 cells in the small intestine to sustain homeostasis.

IgG Fc engineering to modulate antibody effector functions

Therapeutic monoclonal antibodies are among the most effective biotherapeutics to date. An important aspect of antibodies is their ability to bind antigen while at the same time recruit immune effector functions. The majority of approved recombinant monoclonal antibody therapies are of the human IgG1 subclass, which can engage both humoral and cellular components of the immune system. The wealth of information generated about antibodies has afforded investigators the ability to molecularly engineer antibodies to modulate effector functions. Here, we review various antibody engineering efforts intended to improve efficacy and safety relative to the human IgG isotype. Further, we will discuss proposed mechanisms by which engineering approaches led to modified interactions with immune components and provide examples of clinical studies using next generation antibodies.

Intestinal type 1 regulatory T cells migrate to periphery to suppress diabetogenic T cells and prevent diabetes development

Growing insight into the pathogenesis of autoimmune diseases and numerous studies in preclinical models highlights the potential of regulatory T cells to restore tolerance. By using non-obese diabetic (NOD) BDC2.5 TCR-transgenic (Tg), and IL-10 and Foxp3 double-reporter mice, we demonstrate that alteration of gut microbiota during cohousing experiments or treatment with anti-CD3 mAb significantly increase intestinal IL-10-producing type 1 regulatory T (Tr1) cells and decrease diabetes incidence. These intestinal antigen-specific Tr1 cells have the ability to migrate to the periphery via a variety of chemokine receptors such as CCR4, CCR5, and CCR7 and to suppress proliferation of Th1 cells in the pancreas. The ability of Tr1 cells to cure diabetes in NOD mice required IL-10 signaling, as Tr1 cells could not suppress CD4⁺ T cells with a dominant-negative IL-10R. Taken together, our data show a key role of intestinal Tr1 cells in the control of effector T cells and development of diabetes. Therefore, modulating gut-associated lymphoid tissue to boost Tr1 cells may be important in type 1 diabetes management.

Discovery of stimulation-responsive immune enhancers with CRISPR activation

The majority of genetic variants associated with common human diseases map to enhancers, non-coding elements that shape cell-type-specific transcriptional programs and responses to extracellular cues. Systematic mapping of functional enhancers and their biological contexts is required to understand the mechanisms by which variation in non-coding genetic sequences contributes to disease. Functional enhancers can be mapped by genomic sequence disruption, but this approach is limited to the subset of enhancers that are necessary in the particular cellular context being studied. We hypothesized that recruitment of a strong transcriptional activator to an enhancer would be sufficient to drive target gene expression, even if that enhancer was not currently active in the assayed cells. Here we describe a discovery platform that can identify stimulus-responsive enhancers for a target gene independent of stimulus exposure. We used tiled CRISPR activation (CRISPRa) to synthetically recruit a transcriptional activator to sites across large genomic regions (more than 100 kilobases) surrounding two key autoimmunity risk loci, CD69 and IL2RA. We identified several CRISPRa-responsive elements with chromatin features of stimulus-responsive enhancers, including an IL2RA enhancer that harbours an autoimmunity risk variant. Using engineered mouse models, we found that sequence perturbation of the disease-associated Il2ra enhancer did not entirely block Il2ra expression, but rather delayed the timing of gene activation in response to specific extracellular signals. Enhancer deletion skewed polarization of naive T cells towards a pro-inflammatory T helper (TH17) cell state and away from a regulatory T cell state. This integrated approach identifies functional enhancers and reveals how non-coding variation associated with human immune dysfunction alters context-specific gene programs.

Human beta cell mass and function in diabetes: Recent advances in knowledge and technologies to understand disease pathogenesis

BACKGROUND

Plasma insulin levels are predominantly the product of the morphological mass of insulin producing beta cells in the pancreatic islets of Langerhans and the functional status of each of these beta cells. Thus, deficiency in either beta cell mass or function, or both, can lead to insufficient levels of insulin, resulting in hyperglycemia and diabetes. Nonetheless, the precise contribution of beta cell mass and function to the pathogenesis of diabetes as well as the underlying mechanisms are still unclear. In the past, this was largely due to the restricted number of technologies suitable for studying the scarcely accessible human beta cells. However, in recent years, a number of new platforms have been established to expand the available techniques and to facilitate deeper insight into the role of human beta cell mass and function as cause for diabetes and as potential treatment targets.

SCOPE OF REVIEW

This review discusses the current knowledge about contribution of human beta cell mass and function to different stages of type 1 and type 2 diabetes pathogenesis. Furthermore, it highlights standard and newly developed technological platforms for the study of human beta cell biology, which can be used to increase our understanding of beta cell mass and function in human glucose homeostasis.

MAJOR CONCLUSIONS

In contrast to early disease models, recent studies suggest that in type 1 and type 2 diabetes impairment of beta cell function is an early feature of disease pathogenesis while a substantial decrease in beta cell mass occurs more closely to clinical manifestation. This suggests that, in addition to beta cell mass replacement for late stage therapies, the development of novel strategies for protection and recovery of beta cell function could be most promising for successful diabetes treatment and prevention. The use of today's developing and wide range of technologies and platforms for the study of human beta cells will allow for a more detailed investigation of the underlying mechanisms and will facilitate development of treatment approaches to specifically target human beta cell mass and function.

Efficacy and safety of otelixizumab use in new-onset type 1 diabetes mellitus

INTRODUCTION

Type 1 diabetes (T1DM) is an immune-mediated disease induced by antigen-specific T cells infiltrating pancreatic beta cells leading to the progressive loss of endogenous insulin secretion.

AREAS COVERED

The identification of specific components of the autoimmune response favoured the implementation of several immunomodulatory therapies including antiCD3 monoclonal antibody (mAb) called otelixizumab. Otelixizumab is a chimeric monoclonal antibody that targets the ε-chain of the CD3T-lymphocyte surface receptor that has been developed with the aim of short therapeutic courses capable of inducing a remission of T1DM. Clinical trials have been carried out with otelixizumab to evaluate its safety and efficacy, but despite positive results of Phase I and II studies, the results of Phase III studies have been contradictory.

EXPERT OPINION

High doses of otelixizumab have shown beneficial effects on beta cell function whereas a lower dose, which was tested to avoid the adverse effects associated with higher doses, was not effective on beta cells preservation. We believe that otelixizumab is a drug of potential interest for treating new onset T1DM patients and its use in combination with other immunomodulatory agents should be considered as a solution to circumvent adverse effects while maintaining efficacy.

Potential targeting of B7-H4 for the treatment of cancer

Observations noting the presence of white blood cell infiltrates within tumors date back more than a century, however the cellular and molecular mechanisms regulating tumor immunity continue to be elucidated. The recent successful use of monoclonal antibodies to block immune regulatory pathways to enhance tumor-specific immune responses for the treatment of cancer has encouraged the identification of additional immune regulatory receptor/ligand pathways. Over the past several years, a growing body of data has identified B7-H4 (VTCN1/B7x/B7S1) as a potential therapeutic target for the treatment of cancer. The potential clinical significance of B7-H4 is supported by the high levels of B7-H4 expression found in numerous tumor tissues and correlation of the level of expression on tumor cells with adverse clinical and pathologic features, including tumor aggressiveness. The biological activity of B7-H4 has been associated with decreased inflammatory CD4⁺ T-cell responses and a correlation between B7-H4-expressing tumor-associated macrophages and FoxP3⁺ regulatory T cells (Tregs) within the tumor microenvironment. Since B7-H4 is expressed on tumor cells and tumor-associated macrophages in various cancer types, therapeutic blockade of B7-H4 could favorably alter the tumor microenvironment allowing for antigen-specific clearance tumor cells. The present review highlights the therapeutic potential of targeting B7-H4.

Potent and conditional redirected T cell killing of tumor cells using Half DVD-Ig

Novel biologics that redirect cytotoxic T lymphocytes (CTLs) to kill tumor cells bearing a tumor associated antigen hold great promise in the clinic. However, the ability to safely and potently target CD3 on CTL toward tumor associated antigens (TAA) expressed on tumor cells remains a challenge of both technology and biology. Herein we describe the use of a Half DVD-Ig format that can redirect CTL to kill tumor cells. Notably, Half DVD-Ig molecules that are monovalent for each specificity demonstrated reduced non-specific CTL activation and conditional CTL activation upon binding to TAA compared to intact tetravalent DVD-Ig molecules that are bivalent for each specificity, while maintaining good drug like properties and appropriate PK properties.

An allosteric site in the T-cell receptor Cβ domain plays a critical signalling role

The molecular mechanism through which the interaction of a clonotypic αβ T-cell receptor (TCR) with a peptide-loaded major histocompatibility complex (p/MHC) leads to T-cell activation is not yet fully understood. Here we exploit a high-affinity TCR (B4.2.3) to examine the structural changes that accompany binding to its p/MHC ligand (P18-I10/H2-Dd). In addition to conformational changes in complementarity-determining regions (CDRs) of the TCR seen in comparison of unliganded and bound X-ray structures, NMR characterization of the TCR β-chain dynamics reveals significant chemical shift effects in sites removed from the MHC-binding site. Remodelling of electrostatic interactions near the Cβ H3 helix at the membrane-proximal face of the TCR, a region implicated in interactions with the CD3 co-receptor, suggests a possible role for an allosteric mechanism in TCR signalling. The contribution of these TCR residues to signal transduction is supported by mutagenesis and T-cell functional assays.

Entire CD3ε, δ, and γ humanized mouse to evaluate human CD3-mediated therapeutics

T cell–mediated immunotherapy is an attractive strategy for treatment in various disease areas. In this therapeutic approach, the CD3 complex is one of the key molecules to modulate T cell functions; however, in many cases, we cannot evaluate the drug candidates in animal experiments because the therapeutics, usually monoclonal antibodies specific to human CD3, cannot react to mouse endogenous Cd3. Although immunodeficient mice transfused with human hematopoietic stem or precursor cells, known as humanized mice, are available for these studies, mice humanized in this manner are not completely immune competent. In this study we have succeeded in establishing a novel mouse strain in which all the three components of the Cd3 complex — Cd3ε, Cd3δ, and Cd3γ — are replaced by their human counterparts, CD3E, CD3D, and CD3G. Basic immunological assessments have confirmed that this strain of human CD3 EDG–replaced mice are entirely immune competent, and we have also demonstrated that a bispecific antibody that simultaneously binds to human CD3 and a tumor-associated antigen (e.g. ERBB2 or GPC3) can be evaluated in human CD3 EDG–replaced mice engrafted with tumors. Our mouse model provides a novel means to evaluate the in vivo efficacy of human CD3–mediated therapy.

The Induction and Maintenance of Transplant Tolerance Engages Both Regulatory and Anergic CD4+ T cells

Therapeutic tolerance to self-antigens or foreign antigens is thought to depend on constant vigilance by Foxp3⁺ regulatory T cells (Tregs). Previous work using a pancreatic islet allograft model and a short pulse of CD3 antibody therapy has shown that CD8⁺ T cells become anergic and use TGFβ and coinhibitory signaling as their contribution to the tolerance process. Here, we examine the role of CD4⁺ T cells in tolerization by CD3 antibodies. We show that both Foxp3⁺ Tregs and CD4⁺ T cell anergy play a role in the induction of tolerance and its maintenance. Foxp3⁺ Tregs resisted CD3 antibody-mediated depletion, unlike intragraft Th1 CD4⁺ lymphocytes coexpressing granzyme B and Tbx21, which were selectively eliminated. Tregs were mandatory for induction of tolerance as their depletion at the time of CD3 antibody therapy or for a short time thereafter, by an antibody to CD25 (PC61), led to graft rejection. Early treatment with CTLA-4 antibody gave the same outcome. In contrast, neither PC61 nor anti-CTLA-4 given late, at day 100 posttransplant, reversed tolerance once established. Ablation of Foxp3 T cells after diphtheria toxin injection in tolerant Foxp3^DTR recipient mice provided the same outcome. Alloreactive T cells had been rendered intrinsically unresponsive as total CD4⁺ or Treg-deprived CD4⁺ T cells from tolerant recipients were unable to mount donor-specific IFN-γ responses. In addition, intragraft Treg-deprived CD4⁺ T cells lacked proliferative capacities, expressed high levels of the inhibitory receptor PD-1, and exhibited a CD73^hiFR4^hi phenotype, thus reflecting a state of T cell anergy. We conclude that Tregs play a substantive and critical role in guiding the immune system toward tolerance of the allograft, when induced by CD3 antibody, but are less important for maintenance of the tolerant state, where T cell anergy appears sufficient.

Safety and General Considerations for the Use of Antibodies in Infectious Diseases

Monocolonal antibodies are valuable potential new tools for meeting unmet needs in treating infectious dieseases and to provide alternatives and supplements to antibiotics in these times of growing resistance. Especially when considering the ability to screen for antibodies reacting to very diverse target antigens and the ability to design and engineer them to work specifically to hit and overcome their strategies, like toxins and their hiding in specific cells to evade the immuneresponse and their special features enabling killing of the infectious agents and or the cells harbouring them. Antibodies are generally very safe and adverse effects of treatments with therapeutic antibodies are usually related to exaggeration of the intended pharmacology. In this chapter general safety considerations for the use of antibodies is reviewed and the general procedures for nonclinical testing to support their clinical development. Special considerations for anti-infective mAb treatments are provided including the special features that makes nonclinical safety programs for anti-infective mAbs much more simple and restricted. However at a cost since only limited information for clinical safety and modeling can be derived from such programs. Then strategies for optimally designing antibodies are discussed including the use of combination of antibodies. Finally ways to facilitate development of more than the currently only three approved mAb based treatments are discussed with a special focus on high costs and high price and how collaboration and new strategies for development in emerging markets can be a driver for this.

Antibody Binding to CD4 Induces Rac GTPase Activation and Alters T Cell Migration

The use of nondepleting Abs specific for CD4 and CD8 is an effective strategy to tolerize CD4+ and CD8+ T cells in a tissue-specific manner. We reported that coreceptor therapy reverses diabetes in new onset NOD mice. A striking feature of coreceptor-induced remission is the purging of T cells from the pancreatic lymph nodes (PLN) and islets of NOD mice. Evidence indicates that Abs binding to the coreceptors promotes T cell egress from these tissues. The present study examined how coreceptor therapy affects the migration of CD4+ T cells residing in the PLN of NOD mice. Anti-CD4 Ab treatment resulted in an increased frequency of PLN but not splenic CD4+ T cells that exhibited a polarized morphology consistent with a migratory phenotype. Furthermore, PLN CD4+ T cells isolated from anti-CD4 versus control Ab-treated animals displayed increased in vitro chemotaxis to chemoattractants such as sphingosine-1-phosphate and CXCL12. Notably, the latter was dependent on activation of the small Rho GTPases Rac1 and Rac2. Rac1 and Rac2 activation was increased in Ab-bound CD4+ T cells from the PLN but not the spleen, and knockdown of Rac expression blocked the heightened reactivity of Ab-bound PLN CD4+ T cells to CXCL12. Interestingly, Rac1 and Rac2 activation was independent of Rac guanine nucleotide exchange factors known to regulate T cell activity. Therefore, Ab binding to CD4 initiates a novel pathway that involves inflammation-dependent activation of Rac and establishment of altered T cell migratory properties.

Drug Repositioning in Inflammatory Bowel Disease Based on Genetic Information

BACKGROUND

Currently, 200 genetic risk loci have been identified for inflammatory bowel disease (IBD). Although these findings have significantly advanced our insight into IBD biology, there has been little progress in translating this knowledge toward clinical practice, like more cost-efficient drug development. Our aim was to use genetic knowledge to identify drugs that warrant further investigation in IBD treatment.

METHODS

We hypothesized that proteins encoded by IBD candidate genes are potential IBD drug targets because genetic information can increase successful drug identification. We identified drugs that target the proteins encoded by IBD candidate genes using the DrugBank. We included proteins that are in direct protein-protein interaction with proteins encoded by IBD risk genes. Promising potential IBD drugs were selected based on a manual literature search of all identified drugs (PubMed, ClinicalTrials.gov).

RESULTS

We have identified 113 drugs that could potentially be used in IBD treatment. Fourteen are known IBD drugs, 48 drugs have been, or are being investigated in IBD, 19 are being used or being investigated in other inflammatory disorders treatment, and 32 are investigational new drugs that have not yet been registered for clinical use.

CONCLUSIONS

We confirm that proteins encoded by IBD candidate genes are targeted by approved IBD therapies. Furthermore, we show that Food and Drug Administration-approved drugs could possibly be repositioned for IBD treatment. We also identify investigational new drugs that warrant further investigation for IBD treatment. Incorporating this process in IBD drug development will improve the utilization of genetic data and could lead to the improvement of IBD treatment.

Targeted suppression of autoreactive CD8+ T-cell activation using blocking anti-CD8 antibodies

CD8⁺ T-cells play a role in the pathogenesis of autoimmune diseases such as multiple sclerosis and type 1 diabetes. However, drugs that target the entire CD8⁺ T-cell population are not desirable because the associated lack of specificity can lead to unwanted consequences, most notably an enhanced susceptibility to infection. Here, we show that autoreactive CD8⁺ T-cells are highly dependent on CD8 for ligand-induced activation via the T-cell receptor (TCR). In contrast, pathogen-specific CD8⁺ T-cells are relatively CD8-independent. These generic differences relate to an intrinsic dichotomy that segregates self-derived and exogenous antigen-specific TCRs according to the monomeric interaction affinity with cognate peptide-major histocompatibility complex class I (pMHCI). As a consequence, “blocking” anti-CD8 antibodies can suppress autoreactive CD8⁺ T-cell activation in a relatively selective manner. These findings provide a rational basis for the development and in vivo assessment of novel therapeutic strategies that preferentially target disease-relevant autoimmune responses within the CD8⁺ T-cell compartment.

Research and development of therapeutic mAbs: An analysis based on pipeline projects

As the subject of active research and development (R&D) in recent decades, monoclonal antibodies have emerged among the major classes of therapeutic agents for treatment of many human diseases, especially cancers, infections, and immunological disorders. This article surveys the landscape of R&D projects of therapeutic monoclonal antibodies (mAbs), which are mostly used for disease immunotherapy, from a number of perspectives, including therapeutic indications, development phases, participants, and citation of related patents. The results of this research can be used as a reference resource for pharmaceutical researchers, investors, and policymakers in the field of therapeutic mAbs.

Therapeutic anti-CD3 monoclonal antibodies: from bench to bedside

The induction of tolerance is a major goal of immunotherapy. Investigations over the last 20 years have shown that anti-CD3 monoclonal antibodies (mAbs) effectively treat autoimmune disease in animal models and have also shown promise in clinical trials. Tolerance induction by anti-CD3 mAbs is related to the induction of Tregs that control pathogenic autoimmune responses. Here, we review preclinical and clinical studies in which intravenous or mucosal administration of anti-CD3 mAbs has been employed and provide an outlook on future developments to enhance the efficacy of this promising therapeutic approach.

Recombinant antibodies for diagnostics and therapy against pathogens and toxins generated by phage display

Antibodies are valuable molecules for the diagnostic and treatment of diseases caused by pathogens and toxins. Traditionally, these antibodies are generated by hybridoma technology. An alternative to hybridoma technology is the use of antibody phage display to generate recombinant antibodies. This in vitro technology circumvents the limitations of the immune system and allows—in theory—the generation of antibodies against all conceivable molecules. Phage display technology enables obtaining human antibodies from naïve antibody gene libraries when either patients are not available or immunization is not ethically feasible. On the other hand, if patients or immunized/infected animals are available, it is common to construct immune phage display libraries to select in vivo affinity‐matured antibodies. Because the phage packaged DNA sequence encoding the antibodies is directly available, the antibodies can be smoothly engineered according to the requirements of the final application. In this review, an overview of phage display derived recombinant antibodies against bacterial, viral, and eukaryotic pathogens as well as toxins for diagnostics and therapy is given.

Age-related Defects in Ocular and Nasal Mucosal Immune System and the Immunopathology of Dry Eye Disease

Dry eye disease (DED) is a prevalent public health concern that affects up to 30% of adults and is particularly chronic and severe in the elderly. Two interconnected mechanisms cause DED: (1) an age-related dysfunction of lacrimal and meibomian glands, which leads to decreased tear production and/or an increase in tear evaporation; and (2) an age-related uncontrolled inflammation of the surface of the eye triggered by yet-to-be-determined internal immunopathological mechanisms, independent of tear deficiency and evaporation. In this review we summarize current knowledge on animal models that mimic both the severity and chronicity of inflammatory DED and that have been reliably used to provide insights into the immunopathological mechanisms of DED, and we provide an overview of the opportunities and limitations of the rabbit model in investigating the role of both ocular and nasal mucosal immune systems in the immunopathology of inflammatory DED and in testing novel immunotherapies aimed at delaying or reversing the uncontrolled age-related inflammatory DED.

An introduction to biomaterial-based strategies for curbing autoimmunity

Recently, scientists have made significant progress in the development of immunotherapeutics that correct aberrant, autoimmune responses. Yet, concerns about the safety, efficacy, and wide scale applicability continue to hinder use of contemporary, immunology-based strategies. There is a clear need for therapies that finely control molecular and cellular elements of the immune system. Biomaterial engineers have taken up this challenge to develop therapeutics with selective spatial and temporal control of immune cells. In this review, we introduce the immunology of autoimmune disorders, survey the current therapeutic strategies for autoimmune diseases, and highlight the ongoing research efforts to engineer the immune system using biomaterials, for positive therapeutic outcomes in treatment of autoimmune disorders.

Generation of Recombinant Antibodies Against Toxins and Viruses by Phage Display for Diagnostics and Therapy

Antibody phage display is an in vitro technology to generate recombinant antibodies. In particular for pathogens like viruses or toxins, antibody phage display is an alternative to hybridoma technology, since it circumvents the limitations of the immune system. Phage display allows the generation of human antibodies from naive antibody gene libraries when either immunized patients are not available or immunization is not ethically feasible. This technology also allows the construction of immune libraries to select in vivo affinity matured antibodies if immunized patients or animals are available.In this review, we describe the generation of human and human-like antibodies from naive antibody gene libraries and antibodies from immune antibody gene libraries. Furthermore, we give an overview about phage display derived recombinant antibodies against viruses and toxins for diagnostics and therapy.

Immunoglobulin isotype knowledge and application to Fc engineering

Monoclonal antibody-based drugs continue to be one of the most rapidly growing classes of therapeutic molecules. At present, the majority of approved therapeutic antibodies are of the human IgG1 format, which can elicit immune effector functions (e.g., antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity). However, there is a wealth of functional diversity that is present in other isotypes and IgG subclasses that can be exploited to improve clinical safety and performance by increasing stability, reduction of adverse events, modulation of effector functions, and by the engagement of two antigens by a single antibody. This review presents an overview of the different antibody isotypes and subclasses and details how exchanging amino acids between different isotypes (i.e., 'cross-isotypes') can be exploited to generate novel therapeutic platforms.

Trimeprazine increases IRS2 in human islets and promotes pancreatic β cell growth and function in mice

The capacity of pancreatic β cells to maintain glucose homeostasis during chronic physiologic and immunologic stress is important for cellular and metabolic homeostasis. Insulin receptor substrate 2 (IRS2) is a regulated adapter protein that links the insulin and IGF1 receptors to downstream signaling cascades. Since strategies to maintain or increase IRS2 expression can promote β cell growth, function, and survival, we conducted a screen to find small molecules that can increase IRS2 mRNA in isolated human pancreatic islets. We identified 77 compounds, including 15 that contained a tricyclic core. To establish the efficacy of our approach, one of the tricyclic compounds, trimeprazine tartrate, was investigated in isolated human islets and in mouse models. Trimeprazine is a first-generation antihistamine that acts as a partial agonist against the histamine H1 receptor (H1R) and other GPCRs, some of which are expressed on human islets. Trimeprazine promoted CREB phosphorylation and increased the concentration of IRS2 in islets. IRS2 was required for trimeprazine to increase nuclear Pdx1, islet mass, β cell replication and function, and glucose tolerance in mice. Moreover, trimeprazine synergized with anti-CD3 Abs to reduce the progression of diabetes in NOD mice. Finally, it increased the function of human islet transplants in streptozotocin-induced (STZ-induced) diabetic mice. Thus, trimeprazine, its analogs, or possibly other compounds that increase IRS2 in islets and β cells without adverse systemic effects might provide mechanism-based strategies to prevent the progression of diabetes.

Regulatory T cells in atherosclerosis: critical immune regulatory function and therapeutic potential

Atherosclerosis is a chronic inflammatory disease that is mediated by innate and adaptive immune responses. The disease is characterized by sub-endothelial accumulation and modification of lipids in the artery wall triggering an inflammatory reaction which promotes lesion progression and eventual plaque rupture, thrombus formation, and the respective clinical sequelae such as myocardial infarction or stroke. During the past decade, T-cell-mediated immune responses, especially control of pro-inflammatory signals by regulatory T cells (Tregs), have increasingly attracted the interest of experimental and clinical researchers. By suppression of T cell proliferation and secretion of anti-inflammatory cytokines, such as interleukin-10 (IL-10) and transforming growth factor-β, Tregs exert their atheroprotective properties. Atherosclerosis-prone, hyperlipidemic mice harbor systemically less Tregs compared to wild-type mice, suggesting an imbalance of immune cells which affects local and systemic inflammatory and potentially metabolic processes leading to atherogenesis. Restoring or increasing Treg frequency and enhancing their suppressive capacity by various modulations may pose a promising approach for treating inflammatory conditions such as cardiovascular diseases. In this review, we briefly summarize the immunological basics of atherosclerosis and introduce the role and contribution of different subsets of T cells. We then discuss experimental data and current knowledge pertaining to Tregs in atherosclerosis and perspectives on manipulating the adaptive immune system to alleviate atherosclerosis and cardiovascular disease.

Dietary Fatty Acids Directly Impact Central Nervous System Autoimmunity via the Small Intestine

Growing empirical evidence suggests that nutrition and bacterial metabolites might impact the systemic immune response in the context of disease and autoimmunity. We report that long-chain fatty acids (LCFAs) enhanced differentiation and proliferation of T helper 1 (Th1) and/or Th17 cells and impaired their intestinal sequestration via p38-MAPK pathway. Alternatively, dietary short-chain FAs (SCFAs) expanded gut T regulatory (Treg) cells by suppression of the JNK1 and p38 pathway. We used experimental autoimmune encephalomyelitis (EAE) as a model of T cell-mediated autoimmunity to show that LCFAs consistently decreased SCFAs in the gut and exacerbated disease by expanding pathogenic Th1 and/or Th17 cell populations in the small intestine. Treatment with SCFAs ameliorated EAE and reduced axonal damage via long-lasting imprinting on lamina-propria-derived Treg cells. These data demonstrate a direct dietary impact on intestinal-specific, and subsequently central nervous system-specific, Th cell responses in autoimmunity, and thus might have therapeutic implications for autoimmune diseases such as multiple sclerosis.

Recent advances in understanding Type 1 Diabetes

Type 1 diabetes is a multifactorial disease in which genetic and environmental factors play a key role. The triggering event is still obscure, and so are many of the immune events that follow. In this brief review, we discuss the possible role of potential environmental factors and which triggers are believed to have a role in the disease. In addition, as the disease evolves, beta cells are lost and this occurs in a very heterogeneous fashion. Our knowledge of how beta cell mass declines and our view of the disease’s pathogenesis are also debated. We highlight the major hallmarks of disease, among which are MHC-I (major histocompatibility complex class I) expression and insulitis. The dependence versus independence of antigen for the immune infiltrate is also discussed, as both the influence from bystander T cells and the formation of neo-epitopes through post-translational modifications are thought to influence the course of the disease. As human studies are proliferating, our understanding of the disease’s pathogenesis will increase exponentially. This article aims to shed light on some of the burning questions in type 1 diabetes research.

Autoimmune Diabetes: An Overview of Experimental Models and Novel Therapeutics

Type 1 diabetes (T1D) results from a chronic and selective destruction of insulin-secreting β-cells within the islets of Langerhans of the pancreas by autoreactive CD4(+) and CD8(+) T lymphocytes. The use of animal models of T1D was instrumental for deciphering the steps of the autoimmune process leading to T1D. The non-obese diabetic (NOD) mouse and the bio-breeding (BB) rat spontaneously develop the disease similar to the human pathology in terms of the immune responses triggering autoimmune diabetes and of the genetic and environmental factors influencing disease susceptibility. The generation of genetically modified models allowed refining our understanding of the etiology and the pathogenesis of the disease. In the present review, we provide an overview of the experimental models generated and used to gain knowledge on the molecular and cellular mechanisms underlying the breakdown of self-tolerance in T1D and the progression of the autoimmune response. Immunotherapeutic interventions designed in these animal models and translated into the clinical arena in T1D patients will also be discussed.

Mechanisms of Oral Tolerance

Oral tolerance is an active process of local and systemic immune unresponsiveness to orally ingested antigens such as food. The gut immune system must balance responses to commensal bacteria (microbiome), innocuous antigens, and pathogens. Although it is clear that specialized populations of immune cells and lymph nodes create a unique environment in the gut, there remains evidence to suggest that systemic effector sites also are critical to establishing and maintaining oral tolerance.

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.

The case for an autoimmune aetiology of type 1 diabetes

Type 1 diabetes (T1D) develops when there are insufficient insulin-producing beta cells to maintain glucose homeostasis. The prevailing view has been that T1D is caused by immune-mediated destruction of the pancreatic beta cells. However, several recent papers have challenged the long-standing paradigm describing T1D as a tissue-specific autoimmune disease. These authors have highlighted the gaps in our knowledge and understanding of the aetiology of T1D in humans. Here we review the evidence and argue the case for the autoimmune basis of human T1D. In particular, recent analysis of human islet-infiltrating T cells brings important new evidence to this question. Further data in support of the autoimmune basis of T1D from many fields, including genetics, experimental therapies and immunology, is discussed. Finally, we highlight some of the persistent questions relating to the pathogenesis of human type 1 diabetes that remain to be answered.

Trials in the prevention of type 1 diabetes: current and future

A major thrust in type 1 diabetes research is stopping the destruction of beta cells that leads to type 1 diabetes. Research over the past 30 years has defined genetic factors and evidence of autoimmunity that have led to the development of robust prediction models in those at high risk for type 1 diabetes. The ability to identify those at risk and the development of new agents and of collaborative research networks has led to multiple trials aimed at preventing beta cell loss. Trials at all stages of beta cell loss have been conducted: primary prevention (prior to the development of autoimmunity); secondary prevention (after autoantibodies are found) and tertiary prevention (intervening after diagnosis to maintain remaining beta cells). Studies have shown mixed results; evidence of maintained insulin secretion after the time of diagnosis has been described in a number of studies, and primary and secondary prevention is proving to be elusive. Much has been learned from the increasing number of studies in the field in terms of network creation, study design and choice of intervention that will facilitate new avenues of investigation.

Biotherapies targeting T and B cells: from immune suppression to immune tolerance

The field of immunotherapy has undergone a major rejuvenation with the development of monoclonal antibodies and fusion proteins targeting specialized receptors of T and B lymphocytes or cytokines relevant for the differentiation of these cells. This review will focus on autoimmunity, probably the field that benefited most from these new biological therapies that very significantly impacted the modalities of patient's care. The aim is to present the agents which constitute major disease modifying drugs for the treatment of chronic invalidating autoimmune diseases. In doing so, we shall distinguish between agents that globally depress immune responses and those that may selectively target the harmful autoimmune response over long-term while preserving the capacity of the host to react normally to exogenous antigens, in other words, agents promoting 'operational tolerance'.

Apoptotic cell-linked immunoregulation: implications for promoting immune tolerance in transplantation

The induction of alloantigen-specific immune tolerance is the "Holy-Grail" in transplantation. Although it had been previously demonstrated that transient depletion of T cells through apoptosis could lead to long-term immune tolerance, the underlying mechanism responsible for this tolerance induction and maintenance was unknown. In this short article, a novel mechanism for long-term immune tolerance via transient T cell apoptosis will be discussed, based on our recent findings in a CD3-specific antibody treatment-induced immune tolerance mouse model. Transforming growth factor-β, which is produced by immature dendritic cells whilst they phagocytose apoptotic T cells and by macrophages, plays an important role in initiating long-term immune tolerance. A possible model of how allospecific-immune tolerance can be induced in order to prevent allograft rejection in transplantation will be also proposed.

Differential sensitivity of regulatory and effector T cells to cell death: a prerequisite for transplant tolerance

Despite significant progress achieved in transplantation, immunosuppressive therapies currently used to prevent graft rejection are still endowed with severe side effects impairing their efficiency over the long term. Thus, the development of graft-specific, non-toxic innovative therapeutic strategies has become a major challenge, the goal being to selectively target alloreactive effector T cells while sparing CD4⁺Foxp3⁺ regulatory T cells (Tregs) to promote operational tolerance. Various approaches, notably the one based on monoclonal antibodies or fusion proteins directed against the TCR/CD3 complex, TCR coreceptors, or costimulatory molecules, have been proposed to reduce the alloreactive T cell pool, which is an essential prerequisite to create a therapeutic window allowing Tregs to induce and maintain allograft tolerance. In this mini review, we focus on the differential sensitivity of Tregs and effector T cells to the depleting and inhibitory effect of these immunotherapies, with a particular emphasis on CD3-specific antibodies that beyond their immunosuppressive effect, also express potent tolerogenic capacities.

Type 1 diabetes and T regulatory cells

T-regulatory cells (Tregs) play a fundamental role in the creation and maintenance of peripheral tolerance. Deficits in the numbers and/or function of Tregs may be an underlying cause of human autoimmune diseases including type 1 Diabetes Mellitus (T1D), whereas an over-abundance of Tregs can hinder immunity against cancer or pathogens. The importance of Tregs in the control of autoimmunity is well established in a variety of experimental animal models. In mice, manipulating the numbers and/or function of Tregs can decrease pathology in a wide range of contexts, including autoimmunity and it is widely assumed that similar approaches will be possible in humans. T1D, the most prevalent human autoimmune disease, has been a focus of interventions either through direct and indirect in vivo proliferations or through adoptive transfer of the in vitro generated antigen specific and non specific Treg. Some challenges still need to be addressed, including a more specific phenotype marker for Tregs; the reproducibility of satisfactory animal results in human and the reconcile of discrepancies between in vitro and in vivo studies. In this article, we will highlight the role of Tregs in autoimmune disease in general with a special focus on T1D, highlighting progress made and challenges ahead in developing Treg-based therapies.

Oral Administration of OKT3 MAb to Patients with NASH, Promotes Regulatory T-cell Induction, and Alleviates Insulin Resistance: Results of a Phase IIa Blinded Placebo-Controlled Trial

Oral administration of anti-CD3 antibodies induced regulatory T cells (Tregs) alleviating the insulin resistance and liver damage in animal models.

OBJECTIVE

To determine the safety and biological effects of oral OKT3 monoclonal antibody (Balashov et al. Neurology 55:192-8, 2000) in patients with NASH.

DESIGN

In this Phase-IIa trial, four groups of patients with biopsy-proven NASH (n = 9/group) received placebo (group A) or oral OKT3 (group B: 0.2; C: 1.0; D: 5.0 mg/day) for 30 days. Patients were followed for safety, liver enzymes, glucose, lipid profile, oral glucose tolerance test (OGTT), serum cytokines and Tregs.

RESULTS

Oral OKT3 was well tolerated without treatment-related adverse events. OKT3 induced Tregs: with significant increases of CD4(+)LAP(+) (Latency associated peptide) and CD4(+)CD25(+)LAP(+) cells in Group D, and a significant increase in TGF-β in Groups C and D. AST decreased significantly in group D and a trend in Groups B and C. Fasting plasma glucose decreased significantly in all treatment groups compared with placebo. OGTT decreased significantly in Group D. Correlations were observed between the changes in several immune-modulatory effects and clinical biomarkers. While serum anti-CD3 levels where undetectable increases in human anti-mouse antibody levels were observed in Groups C and D.

CONCLUSION

Oral administration of anti-CD3 MAb to patients with NASH was safe and well tolerated. Positive biological effects were noted in several hepatic, metabolic and immunologic parameters. These findings provide the basis for future trials to investigate the effect of oral anti-CD3 MAb immunotherapy in patients with NASH.

The therapeutic potential of regulatory T cells for the treatment of autoimmune disease

INTRODUCTION

Immune tolerance remains the holy grail of therapeutic immunology in the fields of organ and tissue transplant rejection, autoimmune diseases, and allergy and asthma. We have learned that FoxP3(+)CD4(+) regulatory T cells play a vital role in both the induction and maintenance of self-tolerance.

AREAS COVERED

In this opinion piece, we highlight regulatory T cells (Treg) cell biology and novel immune treatments to take advantage of these cells as potent therapeutics. We discuss the potential to utilize Treg and Treg-friendly therapies to replace current general immunosuppressives and induce tolerance as a path towards a drug-free existence without associated toxicities.

EXPERT OPINION

Finally, we opine on the fact that biomedicine sits on the cusp of a new revolution: the use of human cells as versatile therapeutic engines. We highlight the challenges and opportunities associated with the development of a foundational cellular engineering science that provides a systematic framework for safely and predictably regulating cellular behaviors. Although Treg therapy has become a legitimate clinical treatment, development of the therapy will require a better understanding of the underlying Treg biology, manufacturing advances to promote cost effectiveness and combinations with other drugs to alter the pathogenicity/regulatory balance.

Type 1 diabetes: A predictable disease

Type 1 diabetes (T1D) is an autoimmune disease characterized by loss of insulin producing beta cells and reliance on exogenous insulin for survival. T1D is one of the most common chronic diseases in childhood and the incidence is increasing, especially in children less than 5 years of age. In individuals with a genetic predisposition, an unidentified trigger initiates an abnormal immune response and the development of islet autoantibodies directed against proteins in insulin producing beta cells. There are currently four biochemical islet autoantibodies measured in the serum directed against insulin, glutamic decarboxylase, islet antigen 2, and zinc transporter 8. Development of islet autoantibodies occurs before clinical diagnosis of T1D, making T1D a predictable disease in an individual with 2 or more autoantibodies. Screening for islet autoantibodies is still predominantly done through research studies, but efforts are underway to screen the general population. The benefits of screening for islet autoantibodies include decreasing the incidence of diabetic ketoacidosis that can be life threatening, initiating insulin therapy sooner in the disease process, and evaluating safe and specific therapies in large randomized clinical intervention trials to delay or prevent progression to diabetes onset.

The Hsp60 peptide p277 enhances anti-CD3 mediated diabetes remission in non-obese diabetic mice

Type 1 diabetes (T1D) is characterized by the immune-mediated destruction of pancreatic beta cells leading to inadequate glycemic control. Trials with immunomodulatory monotherapies have shown that the disease course can in principle be altered. The observed preservation of endogenous insulin secretion however is typically transient and chronic treatment is often associated with significant side effects. Here we combined anti-CD3 with the Hsp60 peptide p277, two drugs that have been evaluated in Phase 3 trials, to test for enhanced efficacy. Female NOD mice with recent onset diabetes were given 5 μg anti-CD3 i.v., on three consecutive days in combination with 100 μg of p277 peptide in IFA s.c., once weekly for four weeks. Anti-CD3 alone restored normoglycemia in 44% of the mice while combination therapy with anti-CD3 and p277 induced stable remission in 83% of mice. The observed increase in protection occurred only in part through TLR2 signaling and was characterized by increased Treg numbers and decreased insulitis. These results have important implications for the design of combination therapies for the treatment of T1D.