Inhibition of autoimmune diabetes by oral administration of anti-CD3 monoclonal antibody

Latency-associated peptide (LAP)+CD4+ regulatory T cells prevent atherosclerosis by modulating macrophage polarization

RATIONALE

A persistent autoimmune and inflammatory response plays a critical role in the progression of atherosclerosis. The transcription factor forkhead box P3 (Foxp3)+CD4+ regulatory T cells (Foxp3+ Tregs) attenuate atherosclerosis. Latency-associated peptide (LAP)+CD4+ T cells are a new class of Tregs whose role in atherosclerosis is unknown.

OBJECTIVE

To investigate the function of CD4+LAP+ Tregs in inhibiting inflammation and preventing atherosclerosis.

METHODS AND RESULTS

Depletion of CD4+LAP+ Tregs results in aggravated inflammation and atherosclerotic lesions. Mechanistically, CD4+LAP+ Treg depletion was associated with decreased M2-like macrophages and increased Th1 and Th17 cells, characterized by increased unstable plaque promotion and decreased expression of inflammation-resolving factors in both arteries and immune organs. In contrast, adoptive transfer of CD4+LAP+ Tregs to ApoE-/- mice or CD4-/-ApoE-/- mice led to decreased atherosclerotic lesions. Compared with control animals, adoptive transfer of CD4+LAP+ Tregs induced M2-like macrophage differentiation within the atherosclerotic lesion and spleen, associated with increased collagen and α-SMA in plaques and decreased expression of MMP-2 and MMP-9. Mechanistic studies reveal that isolated CD4+LAP+ Tregs exhibit a tolerance phenotype, with increased expression of inhibitory cytokines and coinhibitory molecules. After coculture with CD4+LAP+ Tregs, monocytes/macrophages display typical features of M2 macrophages, including upregulated expression of CD206 and Arg-1 and decreased production of MCP-1, IL-6, IL-1β and TNF-α, which was almost abrogated by transwell and partially TGF-β1 neutralization. RNA-seq analysis showed different gene expression profiles between CD4+LAP+ Tregs and LAP-CD4+ T cells and between CD4+LAP+ Tregs of ApoE-/- mice and CD4+LAP+ Tregs of C57BL/6 mice, of which Fancd2 and IL4i1 may contribute to the powerful inhibitory properties of CD4+LAP+ Tregs. Furthermore, the number and the suppressive properties of CD4+LAP+ Tregs were impaired by oxLDL.

CONCLUSIONS

Our data indicate that the remaining CD4+LAP+ Tregs play a protective role in atherosclerosis by modulating monocyte/macrophage differentiation and regulatory factors, which may partly explain the protective effect of T cells tolerance in atherosclerosis. Moreover, adoptive transfer of CD4+LAP+ Tregs constitutes a novel approach to treat atherosclerosis.

Anti-CD3 inhibits circulatory and tissue-resident memory CD4 T cells that drive asthma exacerbations in mice

BACKGROUND

Exacerbations of asthma are thought to be strongly dependent on reactivation of allergen-induced lung tissue-resident and circulatory memory CD4 T cells. Strategies that broadly inhibit multiple T cell populations might then be useful to limit asthma. Accordingly, we tested whether targeting CD3 during exposure to inhaled allergen could prevent the accumulation of lung-localized effector memory CD4 T cells and block exacerbations of asthmatic inflammation.

METHODS

House dust mite-sensitized and repetitively challenged BL/6 mice were transiently treated therapeutically with F(ab')2 anti-CD3ε and memory T cell responses and lung inflammation were assessed. PBMCs from HDM-allergic donors were examined for the effect of anti-CD3 on expansion of allergen-reactive T cells.

RESULTS

Allergen-sensitized mice undergoing exacerbations of asthma were protected from lung inflammation by transient therapeutic treatment with F(ab')2 anti-CD3. Regardless of whether sensitized mice underwent a secondary or tertiary recall response to inhaled allergen, anti-CD3 inhibited all phenotypes of effector memory CD4 T cells in the lung tissue and lung vasculature by 80%-90%, including those derived from tissue-resident and circulatory memory T cells. This did not depend on Treg cells suggesting it was primarily a blocking effect on memory T cell signaling. Correspondingly, anti-CD3 also strongly inhibited proliferation of human allergen-reactive memory CD4 T cells from allergic individuals. In contrast, the number of surviving tissue-resident memory CD4 T cells that were maintained in the lungs at later times was not robustly reduced by anti-CD3.

CONCLUSION

Anti-CD3 F(ab')2 administration at the time of allergen exposure represents a viable strategy for limiting the immediate activity of allergen-responding memory T cells and asthma exacerbations.

Suppression of anti-drug antibody formation against coagulation factor VIII by oral delivery of anti-CD3 monoclonal antibody in hemophilia A mice

Active tolerance to ingested dietary antigens forms the basis for oral immunotherapy to food allergens or autoimmune self-antigens. Alternatively, oral administration of anti-CD3 monoclonal antibody can be effective in modulating systemic immune responses without T cell depletion. Here we assessed the efficacy of full length and the F(ab')2 fragment of oral anti-CD3 to prevent anti-drug antibody (ADA) formation to clotting factor VIII (FVIII) protein replacement therapy in hemophilia A mice. A short course of low dose oral anti-CD3 F(ab')2 reduced the production of neutralizing ADAs, and suppression was significantly enhanced when oral anti-CD3 was timed concurrently with FVIII administration. Tolerance was accompanied by the early induction of FoxP3+LAP-, FoxP3+LAP+, and FoxP3-LAP+ populations of CD4+ T cells in the spleen and mesenteric lymph nodes. FoxP3+LAP+ Tregs expressing CD69, CTLA-4, and PD1 persisted in spleens of treated mice, but did not produce IL-10. Finally, we attempted to combine the anti-CD3 approach with oral intake of FVIII antigen (using our previously established method of using lettuce plant cells transgenic for FVIII antigen fused to cholera toxin B (CTB) subunit, which suppresses ADAs in part through induction of IL-10 producing FoxP3-LAP+ Treg). However, combining these two approaches failed to improve suppression of ADAs. We conclude that oral anti-CD3 treatment is a promising approach to prevention of ADA formation in systemic protein replacement therapy, albeit via mechanisms distinct from and not synergistic with oral intake of bioencapsulated antigen.

Therapeutic monoclonal antibodies with a focus on hereditary angioedema

Monoclonal antibodies (mAbs) have been shown to be effective and generally safe across a continually expanding list of therapeutic areas. We describe the advantages and limitations of mAbs as a therapeutic option compared with small molecules. Specifically, we discuss a novel mAb in the treatment of hereditary angioedema (HAE), a rare and potentially life-threatening condition characterized by recurrent unpredictable swelling attacks. HAE is mediated by dysregulation of plasma kallikrein activity leading to overproduction of bradykinin. Current prophylactic treatment for HAE includes androgens or replacement of the endogenous plasma kallikrein inhibitor, C1 inhibitor. However, there remains an unmet need for an effective, less burdensome treatment option. Lanadelumab is a fully human mAb targeting plasma kallikrein. Results from clinical trials, including a pivotal Phase 3 study and its ensuing open-label extension study, demonstrated that lanadelumab is associated with few treatment-related adverse events and reduced the rate of HAE attacks. This novel treatment option has the potential to significantly improve the lives of patients with HAE.

Nasal administration of anti-CD3 monoclonal antibody modulates effector CD8+ T cell function and induces a regulatory response in T cells in human subjects

Background

Parenteral anti-CD3 Mab (OKT3) has been used to treat transplant rejection and parental administration of a humanized anti-CD3 Mab (Teplizumab) showed positive effects in diabetes. Nasal administration of anti-CD3 Mab has not been carried out in humans. Nasal anti-CD3 Mab suppresses autoimmune diseases and central nervous system (CNS) inflammation in animal models. We investigated the safety and immune effects of a fully humanized, previously uncharacterized nasal anti-CD3 Mab (Foralumab) in humans and its in vitro stimulatory properties.

Methods

In vitro, Foralumab were compared to UCHT1 anti-human CD3 mAb. For human administration, 27 healthy volunteers (9 per group) received nasal Foralumab or placebo at a dose of 10ug, 50ug, or 250ug daily for 5 days. Safety was assessed and immune parameters measured on day 1 (pre-treatment), 7, 14, and 30 by FACS and by scRNAseq.

Results

In vitro, Foralumab preferentially induced CD8+ T cell stimulation, reduced CD4+ T cell proliferation and lowered expression of IFNg, IL-17 and TNFa. Foralumab induced LAP, TIGIT, and KLRG1 immune checkpoint molecules on CD8+ and CD4+ T cells in a mechanism independent of CD8 T cells. In vivo, nasal Foralumab did not modulate CD3 from the T cell surface at any dose. Immune effects were primarily observed at the 50ug dose and consisted of reduction of CD8+ effector memory cells, an increase in naive CD8+ and CD4+ T cells, and reduced CD8+ T cell granzyme B and perforin expression. Differentially expressed genes observed by scRNAseq in CD8+ and CD4+ populations promoted survival and were anti-inflammatory. In the CD8+ TEMRA population there was induction of TIGIT, TGFB1 and KIR3DL2, indicative of a regulatory phenotype. In the memory CD4+ population, there was induction of CTLA4, KLRG1, and TGFB whereas there was an induction of TGF-B1 in naïve CD4+ T cells. In monocytes, there was induction of genes (HLA-DP, HLA-DQ) that promote a less inflammatory immune response. No side effects were observed, and no subjects developed human anti-mouse antibodies.

Conclusion

These findings demonstrate that nasal Foralumab is safe and immunologically active in humans and presents a new avenue for the treatment of autoimmune and CNS diseases.

Investigational therapies targeting CD3 for prevention and treatment of type 1 diabetes

INTRODUCTION

Immunotherapies for type 1 diabetes mellitus (T1D) have been the focus of intense research over the past few decades; nevertheless, the results of clinical trials have not matched expectations. However, thanks to the recent and promising results on T1D prevention, among all the different immune-intervention tested strategies, clinical evidence on anti-CD3 monoclonal antibodies (mAb) deserve particular attention and in-depth evaluation.

AREAS COVERED

In this narrative review, we introduce the role of T-cells and their co-receptor CD3 in the pathogenesis of T1D and examine the potential of anti-CD3 mAbs as a treatment for preventing or curing T1D. We discuss pre-clinical studies, phase II/III clinical trials, testing the anti-CD3 mAb teplizumab in subjects at T1D high risk, and testing teplizumab and otelixizumab in T1D recent onset patients. In this work we discuss the current evidence gathered on anti-CD3 therapy to offer insights on the treatment strengths, limitations and unmet needs.

EXPERT OPINION

Recent phase II clinical trials with teplizumab in recent-onset T1D seem encouraging, but benefits associated with the use of anti-CD3 mAb in recent-onset T1D are still controversial. A better patient selection, based on immunological profiles and specific biomarkers, is crucial to improve clinical outcomes in T1D immunotherapies.

Recent Advances on the Role and Therapeutic Potential of Regulatory T Cells in Atherosclerosis

Atherosclerotic diseases, including ischemic heart disease and stroke, are a main cause of mortality worldwide. Chronic vascular inflammation via immune dysregulation is critically involved in the pathogenesis of atherosclerosis. Accumulating evidence suggests that regulatory T cells (Tregs), responsible for maintaining immunological tolerance and suppressing excessive immune responses, play an important role in preventing the development and progression of atherosclerosis through the regulation of pathogenic immunoinflammatory responses. Several strategies to prevent and treat atherosclerosis through the promotion of regulatory immune responses have been developed, and could be clinically applied for the treatment of atherosclerotic cardiovascular disease. In this review, we summarize recent advances in our understanding of the protective role of Tregs in atherosclerosis and discuss attractive approaches to treat atherosclerotic disease by augmenting regulatory immune responses.

Insulin-Dependent Maturation of Newly Generated Olfactory Sensory Neurons after Injury

Loss of olfactory sensory neurons (OSNs) after injury to the olfactory epithelium (OE) triggers the generation of OSNs that are incorporated into olfactory circuits to restore olfactory sensory perception. This study addresses how insulin receptor-mediated signaling affects the functional recovery of OSNs after OE injury. Insulin levels were reduced in mice by ablating the pancreatic β cells via streptozotocin (STZ) injections. These STZ-induced diabetic and control mice were then intraperitoneally injected with the olfactotoxic drug methimazole to selectively ablate OSNs. The OE of diabetic and control mice regenerated similarly until day 14 after injury. Thereafter, the OE of diabetic mice contained fewer mature and more apoptotic OSNs than control mice. Functionally, diabetic mice showed reduced electro-olfactogram (EOG) responses and their olfactory bulbs (OBs) had fewer c-Fos-active cells following odor stimulation, as well as performed worse in an odor-guided task compared with control mice. Insulin administered intranasally during days 8-13 after injury was sufficient to rescue recovery of OSNs in diabetic mice compared with control levels, while insulin administration between days 1 and 6 did not. During this critical time window on days 8-13 after injury, insulin receptors are highly expressed and intranasal application of an insulin receptor antagonist inhibits regeneration. Furthermore, an insulin-enriched environment could facilitate regeneration even in non-diabetic mice. These results indicate that insulin facilitates the regeneration of OSNs after injury and suggest a critical stage during recovery (8-13 d after injury) during which the maturation of newly generated OSNs is highly dependent on and promoted by insulin.

Evolving Antibody Therapies for the Treatment of Type 1 Diabetes

Type 1 diabetes (T1D) is widely considered to be a T cell driven autoimmune disease resulting in reduced insulin production due to dysfunction/destruction of pancreatic β cells. Currently, there continues to be a need for immunotherapies that selectively reestablish persistent β cell-specific self-tolerance for the prevention and remission of T1D in the clinic. The utilization of monoclonal antibodies (mAb) is one strategy to target specific immune cell populations inducing autoimmune-driven pathology. Several mAb have proven to be clinically safe and exhibit varying degrees of efficacy in modulating autoimmunity, including T1D. Traditionally, mAb therapies have been used to deplete a targeted cell population regardless of antigenic specificity. However, this treatment strategy can prove detrimental resulting in the loss of acquired protective immunity. Nondepleting mAb have also been applied to modulate the function of immune effector cells. Recent studies have begun to define novel mechanisms associated with mAb-based immunotherapy that alter the function of targeted effector cell pools. These results suggest short course mAb therapies may have persistent effects for regaining and maintaining self-tolerance. Furthermore, the flexibility to manipulate mAb properties permits the development of novel strategies to target multiple antigens and/or deliver therapeutic drugs by a single mAb molecule. Here, we discuss current and potential future therapeutic mAb treatment strategies for T1D, and T cell-mediated autoimmunity.

The Therapeutic Potential of Regulatory T Cells: Challenges and Opportunities

Regulatory T cells (Tregs) are an immunosuppressive subgroup of CD4+ T cells which are identified by the expression of forkhead box protein P3 (Foxp3). The modulation capacity of these immune cells holds an important role in both transplantation and the development of autoimmune diseases. These cells are the main mediators of self-tolerance and are essential for avoiding excessive immune reactions. Tregs play a key role in the induction of peripheral tolerance that can prevent autoimmunity, by protecting self-reactive lymphocytes from the immune reaction. In contrast to autoimmune responses, tumor cells exploit Tregs in order to prevent immune cell recognition and anti-tumor immune response during the carcinogenesis process. Recently, numerous studies have focused on unraveling the biological functions and principles of Tregs and their primary suppressive mechanisms. Due to the promising and outstanding results, Tregs have been widely investigated as an alternative tool in preventing graft rejection and treating autoimmune diseases. On the other hand, targeting Tregs for the purpose of improving cancer immunotherapy is being intensively evaluated as a desirable and effective method. The purpose of this review is to point out the characteristic function and therapeutic potential of Tregs in regulatory immune mechanisms in transplantation tolerance, autoimmune diseases, cancer therapy, and also to discuss that how the manipulation of these mechanisms may increase the therapeutic options.

Structural features of bovine colostral immunoglobulin that confer proteolytic stability in a simulated intestinal fluid

Bovine colostral antibodies, purified from cow's milk produced immediately after calving, have enhanced resistance to degradation by intestinal proteases relative to antibodies from human or bovine serum, making them of particular interest as orally administered therapeutic agents. However, the basis of this resistance is not well defined. We evaluated the stability of AVX-470, a bovine colostral anti-tumor necrosis factor (TNF) polyclonal antibody used in early clinical studies for treatment of ulcerative colitis, using conditions that mimic the human small intestine. AVX-470 was degraded ∼3 times more slowly than human IgG antibodies or infliximab (a monoclonal mouse-human chimeric IgG). Bovine IgG1 antibodies, the primary component of AVX-470, were slowly cleaved to F(ab')2 fragments. In contrast, bovine IgG2 and human IgG1 antibodies were cleaved rapidly into Fab and smaller fragments, pointing to specific regions where additional stability might be gained. Infliximab was modified to incorporate the sequences from these regions, including the bovine IgG1 hinge region and a predicted disulfide bonding motif linking the upper hinge region, the CH1 domain, and the light chain. This infliximab-bovine IgG1 chimera (bovinized infliximab) retained the antigen binding and neutralization activity of the WT sequence but was degraded 9-fold more slowly than the unmodified infliximab. This remarkable increase in stability with as few as 18 amino acid substitutions suggests that this bovinization process is a means to enable oral delivery of proven therapeutic antibodies as well as novel antibodies to targets that have been previously inaccessible to therapies delivered by injection.

γδ T Cell-Secreted XCL1 Mediates Anti-CD3-Induced Oral Tolerance

Oral tolerance is defined as the specific suppression of cellular and/or humoral immune responses to an Ag by prior administration of the Ag through the oral route. Although the investigation of oral tolerance has classically involved Ag feeding, we have found that oral administration of anti-CD3 mAb induced tolerance through regulatory T (Treg) cell generation. However, the mechanisms underlying this effect remain unknown. In this study, we show that conventional but not plasmacytoid dendritic cells (DCs) are required for anti-CD3-induced oral tolerance. Moreover, oral anti-CD3 promotes XCL1 secretion by small intestine lamina propria γδ T cells that, in turn, induces tolerogenic XCR1⁺ DC migration to the mesenteric lymph node, where Treg cells are induced and oral tolerance is established. Consistent with this, TCRδ^-/- mice did not develop oral tolerance upon oral administration of anti-CD3. However, XCL1 was not required for oral tolerance induced by fed Ags, indicating that a different mechanism underlies this effect. Accordingly, oral administration of anti-CD3 enhanced oral tolerance induced by fed MOG_35-55 peptide, resulting in less severe experimental autoimmune encephalomyelitis, which was associated with decreased inflammatory immune cell infiltration in the CNS and increased Treg cells in the spleen. Thus, Treg cell induction by oral anti-CD3 is a consequence of the cross-talk between γδ T cells and tolerogenic DCs in the gut. Furthermore, anti-CD3 may serve as an adjuvant to enhance oral tolerance to fed Ags.

Role of Regulatory Immune Cells and Molecules in Autoimmune Bullous Dermatoses

Autoimmune bullous dermatoses (AIBD) include a series of typical organ-specific autoimmune diseases characterized by extensive mucocutaneous blisters. It is generally accepted to be caused by pathological autoantibodies that directly target specific adhesion components of the skin or the adjacent mucous membranes. Both innate and adaptive immune systems are critically involved in the misguided immune response against self-antigens. Recent studies have indicated that the dysfunction of regulatory T cells, regulatory B cells, and complement regulatory proteins that play essential roles in maintaining a healthy immune environment is also closely related to immune disorders in AIBD. It is important to summarize these studies, elucidate the changes in these regulatory immune cells and molecules for the pathogenesis of AIBD, and reveal the mechanisms by which they lose their ability to regulate immune disorders. In this review, we highlight the role of regulatory immune cells and molecules in the pathogenesis of pemphigus vulgaris and bullous pemphigoid, the two most representative forms of AIBD, and indicate issues that should be addressed in future investigations.

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.

Immunologic Alterations Associated With Oral Delivery of Anti-CD3 (OKT3) Monoclonal Antibodies in Patients With Moderate-to-Severe Ulcerative Colitis

Aim

The aim of this study was to determine the immunologic effects and safety of oral anti-CD3 in patients with ulcerative colitis (UC).

Methods

An open-label pilot study of orally delivered anti-CD3 was performed in patients with moderate-to-severe UC. The primary end points were changes in immunologic parameters and evaluation for safety.

Results

Six subjects received oral OKT3. Biologic effects of oral anti-CD3 included significantly increased proliferation in response to anti-CD3 and anti-inflammatory gene expression profile in peripheral blood mononuclear cells. No serious treatment-related adverse events occurred.

Conclusion

Orally delivered anti-CD3 resulted in immunologic changes in patients with UC.

Immune rebalancing by oral immunotherapy: A novel method for getting the immune system back on track

Immune modulating treatments are often associated with immune suppression or an opposing anti-inflammatory paradigm. As such, there is a risk of exposing patients to infections and malignancies. Contrarily, eliciting only mild immune modulation can be insufficient for alleviating immune-mediated damage. Oral immunotherapy is a novel approach that uses the inherent ability of the gut immune system to generate signals that specifically suppress inflammation at affected sites, without inducing generalized immune suppression. Oral immunotherapy is being developed as a method to rebalance systemic immunity and restore balance, getting it back on track, rather than pushing the immune response too much or too little in opposing directions. Here, I review recent preclinical and clinical data examining the technique and describe its primary advantages.

LAP+CD4+ T cells are elevated among the peripheral blood mononuclear cells and tumor tissue of patients with hepatocellular carcinoma

The purpose of the present study was to investigate the role of latency-associated peptide (LAP)⁺CD4⁺T cells in hepatocellular carcinoma (HCC) immunity. Flow cytometric analysis was performed to detect the proportion of LAP⁺CD4⁺ T cells among the peripheral blood mononuclear cells (PBMCs) of 30 HBV-infected HCC patients at the pre-operative and post-operative stages, as well as 30 hepatitis B virus (HBV)-infected volunteers as a control group. Furthermore, tumor tissues and peri-tumor tissues from 28 patients with HCC, as well as hepatic tissues from 28 HBV-infected patients with benign lesions were subjected to immunohistochemical analysis with double staining for LAP and CD4, and the average number of the LAP⁺CD4⁺T cells in each visual field was quantified. The results indicated that the proportion of LAP+CD4+ T cells in the PBMCs of patients with HCC was significantly higher than that in the control group (1.84±0.85 vs. 0.73±0.39%, P=0.019), while it was significantly reduced after the operation (1.07±0.35, P=0.021), but still slightly, if not significantly, higher compared with that in the control group (P=0.342). Furthermore, the number of LAP⁺CD4⁺ T cells per high-magnification microscopic field (magnification, ×400) in the HCC tissues was 11.25±3.00, which was significantly higher than that in the peri-cancer tissues (5.75±1.00) and that in the HBV-infected hepatic tissues around benign lesions (2.61±0.83). In peri-cancer tissues, LAP⁺CD4⁺ T cells were also significantly more abundant than in control tissues. Furthermore, in the HCC tissues, LAP⁺CD4⁺ T cells were present as clusters in the tumor stroma and closely associated with CD4⁺ T lymphocytes. By contrast, in the peri-cancer liver tissues and HBV-infected hepatic tissues around benign lesions, LAP⁺CD4⁺ T cells were sparsely distributed. LAP⁺CD4⁺ T cells have marked inhibitory effects, and in the peripheral blood and tumor tissues of patients with HCC, they have an important role in the suppression of anti-tumor immunity and in the immune evasion of tumor cells.

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.

Role of LAP+CD4+ T cells in the tumor microenvironment of colorectal cancer

AIM

To investigate the abundance and potential functions of LAP⁺CD4⁺ T cells in colorectal cancer (CRC).

METHODS

Proportions of LAP⁺CD4⁺ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box (Fox)p3, cytotoxic T-lymphocyte-associated protein (CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP^-CD4⁺ and LAP⁺CD4⁺ T cells were isolated using a magnetic cell-sorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β.

RESULTS

The proportion of LAP⁺CD4⁺ T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP⁺CD4⁺ T cells was significantly higher in tumor tissues (11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP⁺CD4⁺ T cells and TNM stage (P < 0.001), distant metastasis (P < 0.001) and serum level of carcinoembryonic antigen (P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP⁺CD4⁺ T cells (95.02% ± 2.87%), which was similar for LAP^-CD4⁺ T cells (94.75% ± 2.76%). In contrast to LAP^-CD4⁺ T cells, LAP⁺CD4⁺ T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5 (P < 0.01). LAP⁺CD4⁺ T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAP^-CD4⁺ T cells.

CONCLUSION

LAP⁺CD4⁺ T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β.

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-6 Inhibits Upregulation of Membrane-Bound TGF-β 1 on CD4+ T Cells and Blocking IL-6 Enhances Oral Tolerance

Oral administration of Ag induces regulatory T cells that express latent membrane-bound TGF-β (latency-associated peptide [LAP]) and have been shown to play an important role in the induction of oral tolerance. We developed an in vitro model to study modulation of LAP⁺ on CD4⁺ T cells. The combination of anti-CD3 mAb, anti-CD28 mAb, and recombinant IL-2 induced expression of LAP on naive CD4⁺ T cells, independent of Foxp3 or exogenous TGF-β. In vitro generated CD4⁺LAP⁺Foxp3^- T cells were suppressive in vitro, inhibiting proliferation of naive CD4⁺ T cells and IL-17A secretion by Th17 cells. Assessing the impact of different cytokines and neutralizing Abs against cytokines, we found that LAP induction was decreased in the presence of IL-6 and IL-21, and to a lesser extent by IL-4 and TNF-α. IL-6 abrogated the in vitro induction of CD4⁺LAP⁺ T cells by STAT3-dependent inhibition of Lrrc32 (glycoprotein A repetitions predominant [GARP]), the adapter protein that tethers TGF-β to the membrane. Oral tolerance induction was enhanced in mice lacking expression of IL-6R by CD4⁺ T cells and by treatment of wild-type mice with neutralizing anti-IL-6 mAb. These results suggest that proinflammatory cytokines interfere with oral tolerance induction and that blocking the IL-6 pathway is a potential strategy for enhancing oral tolerance in the setting of autoimmune and inflammatory diseases.

Intestinal Immunity and Gut Microbiota in Atherogenesis

Atherosclerosis is a chronic inflammatory disease. Interventions targeting the inflammatory process could provide new strategies for preventing atherosclerotic cardiovascular diseases (CVD). Previously, we have reported that oral administration of anti-CD3 antibodies, or active vitamin D₃, reduced atherosclerosis in mice via recruiting regulatory T cells and tolerogenic dendritic cells to the gut-associated lymphoid tissues. From this, it is reasonable to propose that the intestine could be a novel therapeutic target for prevention of atherosclerotic CVD. Recently, the association between cardio-metabolic diseases and gut microbiota has attracted increased attention. Gut microbiota, reported to be highly associated with intestinal immunity and metabolism, were shown to aggravate CVD by contributing to the production of trimethylamine-N-oxide (TMAO), a pro-atherogenic compound. We have also previously investigated the relationship between patient susceptibility to coronary artery disease (CAD) and gut microbiota. We found that the order Lactobacillales was significantly increased and the phylum Bacteroidetes was decreased in CAD patients compared with control patients. In this review article, we discuss the evidence for the relationship between the gut microbiota and cardio-metabolic diseases, and consider the gut microbiota as new potential diagnostic and therapeutic tool for treating CVD.

Review article: novel methods for the treatment of non-alcoholic steatohepatitis - targeting the gut immune system to decrease the systemic inflammatory response without immune suppression

BACKGROUND

The systemic immune system plays a role in inflammation and fibrogenesis associated with non-alcoholic steatohepatitis (NASH) and has become a potential target for drug development. In particular, the gut immune system has been suggested as a means for generating signals that can target the systemic immune system.

AIM

To describe seven novel methods being developed for the treatment of NASH that target the gut immune system for alleviation of the systemic inflammatory response, including oral administration of fatty-liver-derived proteins, anti-CD3 antibodies, tumour necrosis factor fusion protein, anti-lipopolysaccharide antibodies, glucosylceramide, delayed-release mercaptopurine, and soy-derived extracts.

METHODS

A search for these methods for oral immunotherapy for NASH was conducted.

RESULTS

Oral administration of these compounds provides an opportunity for immune modulation without immune suppression, with the advantage of being independent of a single molecular/inflammatory pathway. These modes of oral immune therapy demonstrate superior safety profiles, such that the patient is not exposed to general immune suppression. Moreover, these approaches target the whole spectrum of the disease and may serve as adjuvants to other therapies, such that they provide a platform for treatment of concomitant disorders in patients with NASH, including diabetes and hyperlipidaemia. Most of the compounds reviewed are currently in phase II trials, and it is anticipated that the acquisition of more clinical data in the next few years will enable the use of this new class of drugs for the treatment of NASH.

CONCLUSION

Oral immunotherapy may provide a novel platform for the treatment of NASH.

A plant cell-expressed recombinant anti-TNF fusion protein is biologically active in the gut and alleviates immune-mediated hepatitis and colitis

The orally administered BY-2 plant cell-expressed recombinant anti-TNF fusion protein (PRX-106) (n=6) consists of the soluble form of the human TNF receptor (TNFR) fused to the Fc component of a human antibody IgG1 domain.

AIM

To evaluate the immune modulatory effect of the oral administration of plant cells expressing PRX-106.

METHODS

Mice treated with Concanavalin A (ConA) to induce immune hepatitis was orally treated with cells expressing PRX-106 containing 0.5 or 5μg PRX 106. In the colitis model, TNBS-colitis was induced in mice followed by the oral administration of plant cells expressing PRX-106. The immune modulatory effect was determined through follow-up to assess the clinical effect, histology, and serum cytokine levels and by FACS analysis for lymphocyte subsets.

RESULTS

The oral administration of BY-2 cells expressing PRX-106 alleviated immune-mediated liver injury. Serum AST and ALT levels decreased and were comparable to those of mice that had received high-dose steroids. The beneficial effect was also observed as a marked decrease in hepatic necrosis. In the colitis model, the oral administration of BY-2 plant cells expressing PRX-106 alleviated weight loss associated with immune-mediated colitis and improved bowel histology. A reduction in I-IkB-alpha phosphorylation in treated mice was also observed. These effects were associated with a significant alteration in the distribution of CD4+CD25+FOXP3+ cells.

CONCLUSIONS

Plant cells expressing recombinant anti-TNF fusion protein show biological activity when orally administered, exerting an immune modulatory effect through the alleviation of immune-mediated hepatitis and immune-mediated colitis.

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.

Epicutaneous immunotherapy induces gastrointestinal LAP+ regulatory T cells and prevents food-induced anaphylaxis

BACKGROUND

The attempt to induce oral tolerance as a treatment for food allergy has been hampered by a lack of sustained clinical protection. Immunotherapy by nonoral routes, such as the skin, may be more effective for the development of maintained tolerance to food allergens.

OBJECTIVE

We sought to determine the efficacy and mechanism of tolerance induced by epicutaneous immunotherapy (EPIT) in a model of food-induced anaphylaxis.

METHODS

C3H/HeJ mice were sensitized to ovalbumin (OVA) orally or through the skin and treated with EPIT using OVA-Viaskin patches or oral immunotherapy using OVA. Mice were orally challenged with OVA to induce anaphylaxis. Antigen-specific regulatory T (Treg)-cell induction was assessed by flow cytometry using a transgenic T-cell transfer model.

RESULTS

By using an adjuvant-free model of food allergy generated by epicutaneous sensitization and reactions triggered by oral allergen challenge, we found that EPIT induced sustained protection against anaphylaxis. We show that the gastrointestinal tract is deficient in de novo generation of Treg cells in allergic mice. This defect was tissue-specific, and epicutaneous application of antigen generated a population of gastrointestinal-homing LAP⁺Foxp3^- Treg cells. The mechanism of protection was found to be a novel pathway of direct TGF-β-dependent Treg-cell suppression of mast cell activation, in the absence of modulation of T- or B-cell responses.

CONCLUSIONS

Our data highlight the immune communication between skin and gastrointestinal tract, and identifies novel mechanisms by which epicutaneous tolerance can suppress food-induced anaphylaxis.

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.

Oral immune therapy: targeting the systemic immune system via the gut immune system for the treatment of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are associated with an altered systemic immune response leading to inflammation-mediated damage to the gut and other organs. Oral immune therapy is a method of systemic immune modulation via alteration of the gut immune system. It uses the inherit ability of the innate system of the gut to redirect the systemic innate and adaptive immune responses. Oral immune therapy is an attractive clinical approach to treat autoimmune and inflammatory disorders. It can induce immune modulation without immune suppression, has minimal toxicity and is easily administered. Targeting the systemic immune system via the gut immune system can serve as an attractive novel therapeutic method for IBD. This review summarizes the current data and discusses several examples of oral immune therapeutic methods for using the gut immune system to generate signals to reset systemic immunity as a treatment for IBD.

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.

Oral administration of non-absorbable delayed release 6-mercaptopurine is locally active in the gut, exerts a systemic immune effect and alleviates Crohn's disease with low rate of side effects: results of double blind Phase II clinical trial

Therapy for Crohn's disease (CD) with thiopurines is limited by systemic side effects. A novel formulation of fixed-dose, delayed-release 6-mercaptopurine (DR-6MP) was developed, with local effect on the gut immune system and minimal absorption. The aim of this study was to evaluate the safety and efficacy of DR-6MP in patients with moderately severe CD compared to systemically delivered 6-mercaptopurine (Purinethol). Seventy CD patients were enrolled into a 12-week, double-blind controlled trial. The primary end-point was the percentage of subjects with clinical remission [Crohn's Disease Activity Index (CDAI) < 150] or clinical response (100-point CDAI reduction). Twenty-six (56·5%) and 13 (54·2%) subjects from the DR-6MP and Purinethol cohorts, respectively, completed the study. DR-6MP had similar efficacy to Purinethol following 12 weeks of treatment. However, the time to maximal clinical response was 8 weeks for DR-6MP versus 12 weeks for Purinethol. A higher proportion of patients on DR-6MP showed clinical remission at week 8. A greater improvement in Inflammatory Bowel Disease Questionnaire (IBDQ) score was noted in the DR-6MP group. DR-6MP led to a decrease of CD62(+) expression on T cells, implying a reduction of lymphocyte adhesion to site of inflammation. DR-6MP was safer than Purinethol, with significantly fewer adverse events (AEs). There was no evidence of drug-induced leucopenia in the DR-6MP group; the proportion of subjects who developed hepatotoxicity was lower for the DR-6MP. Non-absorbable DR-6MP is safe and biologically active in the gut. It is clinically effective, exerting a systemic immune response with low systemic bioavailability and a low incidence of side effects.

Oral anti-CD3 immunotherapy for HCV-nonresponders is safe, promotes regulatory T cells and decreases viral load and liver enzyme levels: results of a phase-2a placebo-controlled trial

Orally administered anti-CD3 antibodies are biologically active in the gut through induction of regulatory T cells, exert an immune-modulatory effect, and alleviate insulin resistance and liver damage in patients with NASH.

AIMS

To determine the safety of oral anti-CD3 monoclonal antibody (MAb) immunotherapy in chronic HCV patients with associated immune dysfunction.

METHODS

Four groups (n = 9) of chronic HCV patients who were nonresponders to interferon plus ribavirin therapy received oral placebo (group A) or anti-CD3 MAb at one of three dosage levels for 30 days. Patients were followed for safety parameters and serum levels of liver enzymes, virus, cytokines and regulatory T cells.

RESULTS

Oral anti-CD3 immunotherapy was safe and well tolerated; no treatment-related adverse events were noted. The following improvements were noted relative to pretreatment levels: HCV viral load and AST and ALT levels decreased in the low- and high-dose groups following 30 days of therapy. In two of the treated groups, an increase in regulatory T cells (CD4(+) CD25(+) ) was noted. The positive effects were somewhat more apparent in subjects with initially elevated liver enzyme levels.

CONCLUSIONS

Oral anti-CD3 MAb immunotherapy for nonresponder HCV patients was safe and well tolerated. Trends and statistically significant improvements were observed as reductions in viral load and liver enzyme levels, along with an increase in regulatory T-cell levels. These data support a role for the immune system in the pathogenesis of HCV infection and suggest that this immunotherapy is worthy of evaluation in combination with HCV antiviral drugs.

Intestinal Immunity and Gut Microbiota as Therapeutic Targets for Preventing Atherosclerotic Cardiovascular Diseases

Atherosclerosis is considered a chronic inflammatory disease and an intervention targeting the inflammatory process could be a new therapeutic strategy for preventing atherosclerotic cardiovascular diseases (CVD). We hypothesized that the intestine, which is considered the biggest immune organ in the human body, could be a therapeutic target for preventing CVD. We demonstrated that oral administration of anti-CD3 antibody or an active form of vitamin D3 reduced atherosclerosis in mice via induction of regulatory T cells and tolerogenic dendritic cells in the gut-associated lymphoid tissues. Similar to regulatory immune responses achieved by oral tolerance, our method had systemic effects that ultimately contributed towards atherosclerosis reduction. Recently, we have been interested in the gut microbiota, which have been reported as highly associated with intestinal immunity and systemic metabolic disorders, including obesity and diabetes. Notably, the guts of obese individuals are predominantly colonized by Firmicutes over Bacteroidetes. The association between atherosclerosis and microbiota has been attracting increased attention, and gut microbiota have been shown to participate in the metabolism of a proatherogenic compound called trimethylamine-N-oxide (TMAO) and aggravate CVD. Our investigation of the relationship between susceptibility to CVD and the gut microbiota revealed a characteristic flora type. Here, we discuss the evidence for the relationship between the gut microbiota and cardiometabolic diseases, and consider the gut microbiota as new potential therapeutic targets for treating CVD. (Circ J 2015; 79: 1882-1890).

Cell mediators of autoimmune hepatitis and their therapeutic implications

Autoimmune hepatitis is associated with interactive cell populations of the innate and adaptive immune systems, and these populations are amenable to therapeutic manipulation. The goals of this review are to describe the key cell populations implicated in autoimmune hepatitis and to identify investigational opportunities to develop cell-directed therapies for this disease. Studies cited in PubMed from 1972 to 2014 for autoimmune hepatitis, innate and adaptive immune systems, and therapeutic interventions were examined. Dendritic cells can promote immune tolerance to self-antigens, present neo-antigens that enhance the immune response, and expand the regulatory T cell population. Natural killer cells can secrete pro-inflammatory and anti-inflammatory cytokines and modulate the activity of dendritic cells and antigen-specific T lymphocytes. T helper 2 lymphocytes can inhibit the cytotoxic activities of T helper 1 lymphocytes and limit the expansion of T helper 17 lymphocytes. T helper 17 lymphocytes can promote inflammatory activity, and they can also up-regulate genes that protect against oxidative stress and hepatocyte apoptosis. Natural killer T cells can expand the regulatory T cell population; gamma delta lymphocytes can secrete interleukin-10, stimulate hepatic regeneration, and induce the apoptosis of hepatic stellate cells; and antigen-specific regulatory T cells can dampen immune cell proliferation and function. Pharmacological agents, neutralizing antibodies, and especially the adoptive transfer of antigen-specific regulatory T cells that have been freshly generated ex vivo are evolving as management strategies. The cells within the innate and adaptive immune systems are key contributors to the occurrence of autoimmune hepatitis, and they are attractive therapeutic targets.

Oral mixture of autologous colon-extracted proteins for the Crohn’s disease: A double-blind trial

AIM: To evaluate the safety and efficacy of oral administration of Alequel™, an autologous protein-containing colon extract.

METHODS: A total of 43 patients were enrolled in a randomized, placebo-controlled, double-blind trial. Patients were orally administered with autologous protein-containing colon extract three doses of autologous study drug per week for 15 wk, for a total of 45 doses. Patients were followed for safety parameters. Remission was defined as a Crohn’s disease activity index (CDAI) score of less than or equal to 150. All patients were followed for changes in subsets of T cells by fluorescence-activated cell sorting analysis.

RESULTS: Analysis was performed on a total number of evaluable patients of 14 in the study drug group and 15 in the placebo group. Treatment was well tolerated by all patients. No major treatment-related adverse events were reported or observed in any of the treated patients during the feeding or follow-up periods. Between weeks 6 and 9 of the study, six of the 14 (43%) evaluable subjects who received the study drug achieved a CDAI of 150 or lower. In contrast, five of the 15 (33%) evaluable subjects in the placebo group achieved remission. Between weeks 9 and 12, the remission rates were 50% and 33% for the drug group and placebo group, respectively. Among the drug-treated subjects who achieved remission, the effect of the drug was judged as stable in eight of the 14 subjects as measured by at least two CDAI scores indicating remission in the 15-wk treatment period. A decreased percentage of peripheral natural killer T regulatory cells (a decrease of 28% vs an increase of 16%) and an increased ratio of CD4⁺/CD8⁺ T lymphocytes (an increase of 11% vs a decrease of 9%) were noted in subjects with a significant clinical response.

CONCLUSION: Oral administration of the autologous colonic extract could be a safe and effective for the treatment of patients with moderate to severe Crohn’s disease.

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.

Defective circulating CD4+LAP+ regulatory T cells in patients with dilated cardiomyopathy

There has been increasing evidence that chronic immune activation plays critical roles in the pathogenesis of DCM. CD4(+) LAP(+) Tregs are a newly identified T cell subset with suppressive function on the immune response. This study was designed to investigate whether the circulating frequency and function of CD4(+)LAP(+) Tregs would be impaired in patients with DCM. The results demonstrated that DCM patients had a significantly lower frequency of circulating CD4(+)LAP(+) Tregs compared with control donors. CD4(+)LAP(+) Tregs from DCM patients showed compromised function to suppress proliferation of CD4(+) LAP(-)CD25(int/low) T cells and proliferation and IgG production of B cells. Moreover, B cell proliferation and IgG subset production could be directly suppressed by CD4(+) LAP(+) Tregs. TGF-β and contact-dependent mechanisms were involved in CD4(+)LAP(+) Treg-mediated suppression. Correlation analysis suggested that CD4(+)LAP(+) Treg frequency was positively correlated with LVEF and negatively correlated with serum IgG3 and NT-proBNP concentration in patients with DCM. Our results are the first to demonstrate that the frequencies of CD4(+)LAP(+) Tregs in patients with DCM are reduced and that their suppressive function is compromised. Defective CD4(+) LAP(+) Tregs may be an underlying mechanism of immune activation in DCM patients.

Alteration of regulatory T cells in type 1 diabetes mellitus: a comprehensive review

Type 1 diabetes mellitus (T1DM) is a T cell-mediated autoimmune disease characterized by the destruction of pancreatic β cells. Numerous studies have demonstrated the key role of CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) in the development of T1DM. However, the changes in Treg expression and function as well as the regulation of these activities are not clearly elucidated. Most studies on the role of Tregs in T1DM were performed on peripheral blood rather than pancreas or pancreatic lymph nodes. Tissue-based studies are more difficult to perform, and there is a lack of histological data to support the role of Tregs in T1DM. In spite of this, strategies to increase Treg cell number and/or function have been viewed as potential therapeutic approaches in treating T1DM, and several clinical trials using these strategies have already emerged. Notably, many trials fail to demonstrate clinical response even when Treg treatment successfully boosts Tregs. In view of this, whether a failure of Tregs does exist and contribute to the development of T1DM and whether more Tregs would be clinically beneficial to patients should be carefully taken into consideration before applying Tregs as treatments in T1DM.

The intestinal microbiome in type 1 diabetes

Few concepts in recent years have garnered more disease research attention than that of the intestinal (i.e. 'gut') microbiome. This emerging interest has included investigations of the microbiome's role in the pathogenesis of a variety of autoimmune disorders, including type 1 diabetes (T1D). Indeed, a growing number of recent studies of patients with T1D or at varying levels of risk for this disease, as well as in animal models of the disorder, lend increasing support to the notion that alterations in the microbiome precede T1D onset. Herein, we review these investigations, examining the mechanisms by which the microbiome may influence T1D development and explore how multi-disciplinary analysis of the microbiome and the host immune response may provide novel biomarkers and therapeutic options for prevention of T1D.

Attenuation of early atherosclerotic lesions by immunotolerance with β2 glycoprotein I and the immunomodulatory effectors interleukin 2 and 10 in a murine model

OBJECTIVE

This study assessed the effect of cellular and humoral autoimmune response inhibition after immunization with β2-glycoprotein I (β2-GPI) and the effect of immunomodulation with interleukin (IL)-2 and IL-10 in the development of early atherosclerotic vascular lesion in a murine model. Atherosclerosis is increasingly considered a chronic inflammatory disease with pathogenic autoimmune processes. Regulatory T cells, and their cytokines, have been implicated in the inhibition of the development of atherosclerotic lesions and involved in the immunologic tolerance induction.

METHODS

Eight-week-old male C57BL6 LDL-receptor deficient (LDLR(-/-)) mice were fed a cholesterol-rich (2.8%), high-saturated-fat (82%) diet for a week and divided in five groups. The groups received the following intravenous immunizations: group I (control group): one dose of 5 μg β2-GPI; group II: 5 μg β2-GPI I and 1 μg IL-2; group III: 5 μg β2-GPI and 0.75 μg of IL-10; and group IV: 5 μg β2-GPI, 1 μg IL-2, and 0.75 μg IL-10. The aortas of the mice were assessed 8 weeks after inoculation to determine the aortic lesion size and composition in all groups.

RESULTS

β2-GPI immunization attenuated the early atherosclerotic lesions development compared with the control group (P = .001). Macroscopic and histologic aortic atherosclerotic lesions were significantly decreased in the IL-2 and IL-10-treated groups in β2-GPI-tolerant mice compared with the β2-GPI-tolerant group without cytokine injection (P = .001). The association of both cytokines did not provoke a major inhibition in the atherosclerosis development when compared with groups injected with the two cytokines separately.

CONCLUSIONS

The immunotolerance induction against β2-GPI attenuates the development of atherosclerosis lesions in an animal model, enhanced by downregulation of the cellular and humoral autoimmune response provoked by IL-2 and IL-10.

Impaired circulating CD4+ LAP+ regulatory T cells in patients with acute coronary syndrome and its mechanistic study

OBJECTIVE

CD4(+) latency-associated peptide (LAP)(+) regulatory T cells (Tregs) are a newly discovered T cell subset in humans and the role of these cells in patients with acute coronary syndrome (ACS) has not been explored. We designed to investigate whether circulating frequency and function of CD4(+)LAP(+) Tregs are defective in ACS.

METHODS

One hundred eleven ACS patients (acute myocardial infarction and unstable angina) and 117 control patients were enrolled in the study. The control patients consisted of chronic stable angina (CSA) and chest pain syndrome (CPS). The frequencies of circulating CD4(+)LAP(+) Tregs and the expression of the transmembrane protein glycoprotein-A repetitions predominant (GARP) on CD4(+) T cells were determined by flow cytometry. The function of CD4(+)LAP(+) Tregs was detected using thymidine uptake. Serum interleukin-10 (IL-10) and transforming growth factor-β protein (TGF-β) levels were detected using ELISA and expression of GARP mRNA in peripheral blood mononuclear cells (PBMCs) was measured by real time-polymerase chain reaction.

RESULTS

We found ACS patients had a significantly lower frequency of circulating CD4(+)LAP(+) Tregs, and the function of these cells was reduced compared to controls. The expression of GARP in CD4(+) T cells and the serum levels of TGF-β in ACS patients were lower than those of control patients. The serum levels of IL-10 were similar between the two cohorts.

CONCLUSIONS

A novel regulatory T cell subset, defined as CD4(+)LAP(+) T cells is defective in ACS patients.

Downregulation of CD4+LAP+ and CD4+CD25+ regulatory T cells in acute coronary syndromes

Background. Regulatory T (Treg) cells play a protective role in atherosclerosis prone models and are related to the onset of acute coronary syndromes (ACS, including non-ST-elevation ACS (NSTEACS) and ST-elevation acute myocardial infarction (STEAMI)). CD4+LAP+ Treg cells are a novel subset of Tregs that have been found to ameliorate atherosclerosis in ApoE^−/− mice, and these cells also exist in humans. The present study was designed to investigate whether CD4+LAP+ Treg cells are involved in the onset of ACS. Methods. The frequencies of CD4+LAP+ and CD4+CD25+ Treg cells were detected using flow cytometric analysis, and the plasma IL-10 and TGF-β1 levels were measured using an ELISA in 29 stable angina (SA) patients, 30 NSTEACS patients, 27 STEAMI patients, and a control group (30 cases). Results. The results revealed a significant decrease in the frequencies of CD4+LAP+ and CD4+CD25+ Treg cells and in the levels of IL-10 and TGF-β1 in patients with ACS compared with those in the SA and control groups. Conclusions. The decrease in the frequencies of CD4+LAP+ and CD4+CD25+ Treg cells may play a role in the onset of ACS.

Probiotic VSL#3-induced TGF-β ameliorates food allergy inflammation in a mouse model of peanut sensitization through the induction of regulatory T cells in the gut mucosa

SCOPE

Among food allergies, peanut allergy is frequently associated with severe anaphylactic reactions. In the need for safe and effective therapeutic strategies, probiotics may be considered on the basis of their immunomodulatory properties. The aim of the present study was to investigate the immunological mediators involved in the effects of probiotic VSL#3 oral supplementation on Th2 inflammation and anaphylaxis in a mouse model of peanut allergy.

METHODS AND RESULTS

VSL#3 supplementation to peanut-sensitized mice was effective in ameliorating anaphylaxis and Th2-mediated inflammation, by promoting regulatory responses in the jejunum mucosa and in the mesenteric lymph node, as evaluated by ELISA, real-time PCR, histologic, and immunohistochemical analysis. Probiotic-induced TGF-β mediates its protective effects through the induction of regulatory T cells expressing FOXP3 and/or latency-associated peptide, as proven by in vivo blockade of TGF-β in VSL#3-treated mice with a neutralizing monoclonal antibody one day before challenge.

CONCLUSION

TGF-β, induced in the gut by VSL#3 supplementation, is capable of reducing the Th2 inflammation associated with food anaphylaxis in a mouse model of peanut sensitization. TGF-β acts through the induction/maintenance of regulatory T cells expressing FOXP3 and/or latency-associated peptide. Probiotics supplementation may represent an effective and safe strategy for treating food allergies in adult population.

Combination treatment with anti-CD20 and oral anti-CD3 prevents and reverses autoimmune diabetes

Type 1 diabetes (T1D) is a T cell-mediated autoimmune disease, although B cells also play an important role in T1D development. Both T cell- and B cell-directed immunotherapies have shown efficacy in the prevention and reversal of T1D. However, whether the combined strategy of targeting both T and B cells could further improve therapeutic efficacy remains to be explored. We show that combined treatment with intravenous antihuman CD20 (hCD20) and oral anti-CD3 significantly delays diabetes development in prediabetic hCD20 transgenic NOD mice. More importantly, the combined treatment reverses diabetes in >60% of mice newly diagnosed with diabetes. Further mechanistic studies demonstrated that the addition of oral anti-CD3 to the B-cell depletion therapy synergistically enhances the suppressive function of regulatory T cells. Of note, the oral anti-CD3 treatment induced a fraction of interleukin (IL)-10-producing CD4 T cells in the small intestine through IL-10- and IL-27-producing dendritic cells. Thus, the findings demonstrate that combining anti-CD20 and oral anti-CD3 is superior to anti-CD20 monotherapy for restoring normoglycemia in diabetic NOD mice, providing important preclinical evidence for the optimization of B cell-directed therapy for T1D.

Anti-CD3 clinical trials in type 1 diabetes mellitus

Two humanized, anti-CD3 mAbs with reduced FcR binding, teplizumab and otelixizumab, have been evaluated in over 1500 subjects, ages 7-45, with new and recently diagnosed T1D with a range of intravenous doses (3-48mg) and regimens (6-14 days, single or repeat courses). In general, studies that used adequate dosing demonstrated improvement in stimulated C-peptide responses and reduced need for exogenous insulin for two years and even longer after diagnosis. Drug treatment causes a transient reduction in circulating T cells, but the available data suggest that the mechanism of action may involve induction of regulatory mechanisms. The adverse effects of anti-CD3 treatment are infusion-related and transient. The studies have identified significant differences in efficacy among patient groups suggesting that a key aspect for development of this immune therapy is identification of the demographic, metabolic, and immunologic features that distinguish subjects who are most likely to show beneficial clinical responses.

Immune therapy for nonalcoholic steatohepatitis: are we there yet?

Metabolic syndrome, obesity, and nonalcoholic steatohepatitis are associated with a state of chronic inflammation. The immune system and the inflammatory cascade can be involved in the development of any of the above common conditions. This association raises the question of whether immune therapy can be used for the treatment of nonalcoholic steatohepatitis. Although immune therapy is not yet feasible for clinical use, here, we review some of the recent data on the potential role of the various arms of the immune system in the development of nonalcoholic steatohepatitis and several potential therapeutic targets.