Role for IL-10 in suppression mediated by peptide-induced regulatory T cells in vivo

Tolerance-inducing therapies in coeliac disease - mechanisms, progress and future directions

Coeliac disease is an autoinflammatory condition caused by immune reactions to cereal gluten proteins. Currently, the only available treatment for the condition is a lifelong avoidance of gluten proteins in the diet. There is an unmet need for alternative therapies. Coeliac disease has a strong association with certain HLA-DQ allotypes (DQ2.5, DQ2.2 and DQ8), and these disease-associated HLA-DQ molecules present deamidated gluten peptides to gluten-specific CD4+ T cells. The gluten-specific CD4+ T cells are the drivers of the immune reactions leading to coeliac disease. Once established, the clonotypes of gluten-specific CD4+ T cells persist for decades, explaining why patients must adhere to a gluten-free diet for life. Given the key pathogenic role of gluten-specific CD4+ T cells, tolerance-inducing therapies that target these T cells are attractive for treatment of the disorder. Lessons learned from coeliac disease might provide clues for treatment of other HLA-associated diseases for which the disease-driving antigens are unknown. Thus, intensive efforts have been and are currently implemented to bring an effective tolerance-inducing therapy for coeliac disease. This Review discusses mechanisms of the various approaches taken, summarizing the progress made, and highlights future directions in this field.

Increased EZH2 function in regulatory T cells promotes their capacity to suppress autoimmunity by driving effector differentiation prior to activation

The immunosuppressive function of regulatory T (Treg) cells is essential for maintaining immune homeostasis. Enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27 (H3K27) methyltransferase, plays a key role in maintaining Treg cell function upon CD28 co-stimulation, and Ezh2 deletion in Treg cells causes autoimmunity. Here we assessed whether increased EZH2 activity in Treg cells would improve Treg cell function. Using an Ezh2 gain-of-function mutation, Ezh2 Y641F , we found that Treg cells expressing Ezh2 Y641F displayed an increased effector Treg phenotype and were poised for improved homing to organ tissues. Expression of Ezh2 Y641F in Treg cells led to more rapid remission from autoimmunity. H3K27me3 profiling and transcriptomic analysis revealed a redistribution of H3K27me3, which prompted a gene expression profile in naïve Ezh2 Y641F Treg cells that recapitulated aspects of CD28-activated Ezh2 WT Treg cells. Altogether, increased EZH2 activity promotes the differentiation of effector Treg cells that can better suppress autoimmunity.

Highlights

EZH2 function promotes effector differentiation of Treg cells.EZH2 function promotes Treg cell migration to organ tissues.EZH2 function in Treg cells improves remission from autoimmunity.EZH2 function poises naïve Treg cells to adopt a CD28-activated phenotype.

High affinity chimeric antigen receptor signaling induces an inflammatory program in human regulatory T cells

Regulatory T cells (Tregs) are promising cellular therapies to induce immune tolerance in organ transplantation and autoimmune disease. The success of chimeric antigen receptor (CAR) T-cell therapy for cancer has sparked interest in using CARs to generate antigen-specific Tregs. Here, we compared CAR with endogenous T cell receptor (TCR)/CD28 activation in human Tregs. Strikingly, CAR Tregs displayed increased cytotoxicity and diminished suppression of antigen-presenting cells and effector T (Teff) cells compared with TCR/CD28 activated Tregs. RNA sequencing revealed that CAR Tregs activate Teff cell gene programs. Indeed, CAR Tregs secreted high levels of inflammatory cytokines, with a subset of FOXP3+ CAR Tregs uniquely acquiring CD40L surface expression and producing IFNγ. Interestingly, decreasing CAR antigen affinity reduced Teff cell gene expression and inflammatory cytokine production by CAR Tregs. Our findings showcase the impact of engineered receptor activation on Treg biology and support tailoring CAR constructs to Tregs for maximal therapeutic efficacy.

A new approach to overcoming resistance to immunotherapy: nanotechnology

Immunotherapy for immune response has ushered in a new era of cancer treatment. In recent years, new immunotherapeutic agents have been introduced into clinical trials and even approved for marketing. However, the widespread use of immunotherapeutic agents faces an unavoidable challenge: immunotherapy does not work at all for some patients, or has good efficacy in the initial phase, but immunotherapy resistance develops within a short period of time, and immunotherapy can also cause serious adverse effects such as autoimmune inflammation and non-specific inflammation. How to enable patients to overcome drug resistance, reduce the toxic side effects of drugs, enhance patient compliance and improve patient survival has become a problem that clinicians have to face. The advent of nanotechnology provides an encouraging platform for immunotherapy. It can not only improve the bioavailability and stability of drugs and reduce toxic side effects, but also reduce resistance to immunotherapy. Here, we discuss these research advances and discuss potential challenges and future directions.

The role of mitochondria in the resistance of melanoma to PD-1 inhibitors

Malignant melanoma is one of the most common tumours and has the highest mortality rate of all types of skin cancers worldwide. Traditional and novel therapeutic approaches, including surgery, targeted therapy and immunotherapy, have shown good efficacy in the treatment of melanoma. At present, the mainstay of treatment for melanoma is immunotherapy combined with other treatment strategies. However, immune checkpoint inhibitors, such as PD-1 inhibitors, are not particularly effective in the clinical treatment of patients with melanoma. Changes in mitochondrial function may affect the development of melanoma and the efficacy of PD-1 inhibitors. To elucidate the role of mitochondria in the resistance of melanoma to PD-1 inhibitors, this review comprehensively summarises the role of mitochondria in the occurrence and development of melanoma, targets related to the function of mitochondria in melanoma cells and changes in mitochondrial function in different cells in melanoma resistant to PD-1 inhibitors. This review may help to develop therapeutic strategies for improving the clinical response rate of PD-1 inhibitors and prolonging the survival of patients by activating mitochondrial function in tumour and T cells.

How to overcome resistance to immune checkpoint inhibitors in colorectal cancer: From mechanisms to translation

Immunotherapy, especially with immune checkpoint inhibitors (ICIs), has shown advantages in cancer treatment and is a new hope for patients who have failed multiline therapy. However, in colorectal cancer (CRC), the benefit is limited to a small subset of patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) metastatic CRC (mCRC). In addition, 45% to 60% of dMMR/MSI-H mCRC patients showed primary or acquired resistance to ICIs. This means that these patients may have potential unknown pathways mediating immune escape. Almost all mismatch repair-proficient (pMMR) or microsatellite-stable (MSS) mCRC patients do not benefit from ICIs. In this review, we discuss the mechanisms of action of ICIs and their current status in CRC. We then discuss the mechanisms of primary and acquired resistance to ICIs in CRC. Finally, we discuss promising therapeutic strategies to overcome resistance to ICIs in the clinic.

Cancer Resistance to Immunotherapy: Molecular Mechanisms and Tackling Strategies

Cancer immunotherapy has fundamentally altered cancer treatment; however, its efficacy is limited to a subset of patients in most clinical settings. The immune system plays a key role in cancer progression from tumor initiation to the metastatic state. Throughout the treatment course, communications between the immune cells in the tumor microenvironment and the immune macroenvironment, as well as interactions between the immune system and cancer cells, are dynamic and constantly evolving. To improve the clinical benefit for patients who do not respond completely to immunotherapy, the molecular mechanisms of resistance to immunotherapy must be elucidated in order to develop effective strategies to overcome resistance. In an attempt to improve and update the current understanding of the molecular mechanisms that hinder immunotherapy, we discuss the molecular mechanisms of cancer resistance to immunotherapy and the available treatment strategies.

Immune status for monitoring and treatment of bladder cancer

The high recurrence rate of non-muscle invasive bladder cancer (BC) and poor prognosis of advanced BC are therapeutic challenges that need to be solved. Bacillus Calmette-Guerin (BCG) perfusion was the pioneer immunotherapy for early BC, and the discovery of immune checkpoint inhibitors has created a new chapter in the treatment of advanced BC. The benefit of immunotherapy is highly anticipated, but its effectiveness still needs to be improved. In this review, we collated and analysed the currently available information and explored the mechaisms by which the internal immune imbalance of BC leads to tumour progression. The relationship between immunity and progression and the prognosis of BC has been explored through tests using body fluids such as blood and urine. These analytical tests have attempted to identify specific immuyne cells and cytokines to predict treatment outcomes and recurrence. The diversity and proportion of immune and matrix cells in BC determine the heterogeneity and immune status of tumours. The role and classification of immune cells have also been redefined, e.g., CD4 cells having recognised cytotoxicity in BC. Type 2 immunity, including that mediated by M2 macrophages, Th2 cells, and interleukin (IL)-13, plays an important role in the recurrence and progression of BC. Pathological fibrosis, activated by type 2 immunity and cancer cells, enhances the rate of cancer progression and irreversibility. Elucidating the immune status of BC and clarifying the mechanisms of action of different cells in the tumour microenvironment is the research direction to be explored in the future.

High-dimensional analysis defines multicytokine T-cell subsets and supports a role for IL-21 in atopic dermatitis

BACKGROUND

Flow cytometry is a well-accepted approach for immune profiling; however, its value is restricted by the limited number of markers that can be analyzed simultaneously. Mass cytometry/CyTOF offers broad-scale immune characterization integrating large number of parameters. While partial blood phenotyping was reported in atopic dermatitis (AD), patients' comprehensive profiling, critical for leveraging new targeted treatments, is not available. IL-21 may be involved in inflammatory skin diseases but its role in AD is not well established.

METHODS

We studied T-cell polarization in the blood of 20 moderate-to-severe AD and 15 controls. Using CyTOF and an unsupervised analysis, we measured the frequencies and mean metal intensities of activated polar CD4⁺ /CD8⁺ T-cell subsets. Immunohistochemistry, immunofluorescence, and qRT-PCR were used to analyze skin samples.

RESULTS

Examining 24 surface, intracellular markers, and transcription factors, we identified six CD4⁺ and five CD8⁺ T-cell metaclusters. A CD4⁺ skin-homing IL-13⁺ monocytokine and a novel IL-13⁺ IL-21⁺ multicytokine metaclusters were increased in AD vs. controls (p < .01). While IL-13 signature characterized both clusters, levels were significantly higher in the IL-21⁺ group. Both clusters correlated with AD severity (r = 0.49, p = .029). Manual gating corroborated these results and identified additional multicytokine subsets in AD. Immunohistochemistry and immunofluorescence, validated by mRNA expression, displayed significantly increasedIL-21 counts and colocalization with IL-13/IL-4R in AD skin.

CONCLUSION

A multicytokine signature characterizes moderate-to-severe AD, possibly explaining partial therapeutic responses to one cytokine targeting, particularly in severe patients. Prominent IL-21 signature in blood and skin hints for a potential pathogenic role of IL-21 in AD.

Induction of Tolerance to Therapeutic Proteins With Antigen-Processing Independent T Cell Epitopes: Controlling Immune Responses to Biologics

The immune response to exogenous proteins can overcome the therapeutic benefits of immunotherapies and hamper the treatment of protein replacement therapies. One clear example of this is haemophilia A resulting from deleterious mutations in the FVIII gene. Replacement with serum derived or recombinant FVIII protein can cause anti-drug antibodies in 20-50% of individuals treated. The resulting inhibitor antibodies override the benefit of treatment and, at best, make life unpredictable for those treated. The only way to overcome the inhibitor issue is to reinstate immunological tolerance to the administered protein. Here we compare the various approaches that have been tested and focus on the use of antigen-processing independent T cell epitopes (apitopes) for tolerance induction. Apitopes are readily designed from any protein whether this is derived from a clotting factor, enzyme replacement therapy, gene therapy or therapeutic antibody.

Conversion of Anergic T Cells Into Foxp3- IL-10+ Regulatory T Cells by a Second Antigen Stimulus In Vivo

T cell anergy is a common mechanism of T cell tolerance. However, although anergic T cells are retained for longer time periods in their hosts, they remain functionally passive. Here, we describe the induction of anergic CD4⁺ T cells in vivo by intravenous application of high doses of antigen and their subsequent conversion into suppressive Foxp3^- IL-10⁺ Tr1 cells but not Foxp3⁺ Tregs. We describe the kinetics of up-regulation of several memory-, anergy- and suppression-related markers such as CD44, CD73, FR4, CD25, CD28, PD-1, Egr-2, Foxp3 and CTLA-4 in this process. The conversion into suppressive Tr1 cells correlates with the transient intracellular CTLA-4 expression and required the restimulation of anergic cells in a short-term time window. Restimulation after longer time periods, when CTLA-4 is down-regulated again retains the anergic state but does not lead to the induction of suppressor function. Our data require further functional investigations but at this stage may suggest a role for anergic T cells as a circulating pool of passive cells that may be re-activated into Tr1 cells upon short-term restimulation with high and systemic doses of antigen. It is tentative to speculate that such a scenario may represent cases of allergen responses in non-allergic individuals.

Peptide allergen-specific immunotherapy for allergic airway diseases-State of the art

Allergen-specific immunotherapy (AIT) is the only means of altering the natural immunological course of allergic diseases and achieving long-term remission. Pharmacological measures are able to suppress the immune response and/or ameliorate the symptoms but there is a risk of relapse soon after these measures are withdrawn. Current AIT approaches depend on the administration of intact allergens, often comprising crude extracts of the allergen. We propose that the challenges arising from current approaches, including the risk of serious side-effects, burdensome duration of treatment, poor compliance and high cost, are overcome by application of peptides based on CD4⁺ T cell epitopes rather than whole allergens. Here we describe evolving approaches, summarize clinical trials involving peptide AIT in allergic rhinitis and asthma, discuss the putative mechanisms involved in their action, address gaps in evidence and propose future directions for research and clinical development.

Advancement of antigen-specific immunotherapy: knowledge transfer between allergy and autoimmunity

Targeted restoration of immunological tolerance to self-antigens or innocuous environmental allergens represents the ultimate aim of treatment options in autoimmune and allergic disease. Antigen-specific immunotherapy (ASI) is the only intervention that has proven disease-modifying efficacy as evidenced by induction of long-term remission in a number of allergic conditions. Mounting evidence is now indicating that specific targeting of pathogenic T cells in autoinflammatory and autoimmune settings enables effective restoration of immune homeostasis between effector and regulatory cells and alters the immunological course of disease. Here, we discuss the key lessons learned during the development of antigen-specific immunotherapies and how these can be applied to inform future interventions. Armed with this knowledge and current high-throughput technology to track immune cell phenotype and function, it may no longer be a matter of ‘if’ but ‘when’ this ultimate aim of targeted tolerance restoration is realised.

Chromatin Priming Renders T Cell Tolerance-Associated Genes Sensitive to Activation below the Signaling Threshold for Immune Response Genes

Immunological homeostasis in T cells is maintained by a tightly regulated signaling and transcriptional network. Full engagement of effector T cells occurs only when signaling exceeds a critical threshold that enables induction of immune response genes carrying an epigenetic memory of prior activation. Here we investigate the underlying mechanisms causing the suppression of normal immune responses when T cells are rendered anergic by tolerance induction. By performing an integrated analysis of signaling, epigenetic modifications, and gene expression, we demonstrate that immunological tolerance is established when both signaling to and chromatin priming of immune response genes are weakened. In parallel, chromatin priming of immune-repressive genes becomes boosted, rendering them sensitive to low levels of signaling below the threshold needed to activate immune response genes. Our study reveals how repeated exposure to antigens causes an altered epigenetic state leading to T cell anergy and tolerance, representing a basis for treating auto-immune diseases.

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Activation of immune response genes is suppressed in tolerant T cells

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Epigenetic priming of repressive genes is boosted when tolerance is established

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Inhibitory receptor genes have a lower threshold of activation in tolerant cells

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Induction of tolerance by peptides points toward a therapy for multiple sclerosis

Age-Related Changes in Thymic Central Tolerance

Thymic epithelial cells (TECs) and hematopoietic antigen presenting cells (HAPCs) in the thymus microenvironment provide essential signals to self-reactive thymocytes that induce either negative selection or generation of regulatory T cells (Treg), both of which are required to establish and maintain central tolerance throughout life. HAPCs and TECs are comprised of multiple subsets that play distinct and overlapping roles in central tolerance. Changes that occur in the composition and function of TEC and HAPC subsets across the lifespan have potential consequences for central tolerance. In keeping with this possibility, there are age-associated changes in the cellular composition and function of T cells and Treg. This review summarizes changes in T cell and Treg function during the perinatal to adult transition and in the course of normal aging, and relates these changes to age-associated alterations in thymic HAPC and TEC subsets.

The Mechanism of Action of Antigen Processing Independent T Cell Epitopes Designed for Immunotherapy of Autoimmune Diseases

Immunotherapy with antigen-processing independent T cell epitopes (apitopes) targeting autoreactive CD4⁺ T cells has translated to the clinic and been shown to modulate progression of both Graves’ disease and multiple sclerosis. The model apitope (Ac1-9[4Y]) renders antigen-specific T cells anergic while repeated administration induces both Tr1 and Foxp3⁺ regulatory cells. Here we address why CD4⁺ T cell epitopes should be designed as apitopes to induce tolerance and define the antigen presenting cells that they target in vivo. Furthermore, we reveal the impact of treatment with apitopes on CD4⁺ T cell signaling, the generation of IL-10-secreting regulatory cells and the systemic migration of these cells. Taken together these findings reveal how apitopes induce tolerance and thereby mediate antigen-specific immunotherapy of autoimmune diseases.

The Fetal-Maternal Immune Interface in Uterus Transplantation

Uterus transplants (UTxs) have been performed worldwide. Overall frequencies have been low, but globally initiated UTx programs are expected to increase clinical implementation. The uterus constitutes a unique immunological environment with specific features of tissue renewal and a receptive endometrium. Decidual immune cells facilitate embryo implantation and placenta development. Although UTx adds to the complexity of immunity during pregnancy and transplantation, the procedure provides a unique clinical and experimental model. We posit that understanding the distinct immunological properties at the interface of the transplanted uterus, the fetus and maternal circulation might provide valuable novel insights while improving outcomes for UTx. Here, we discuss immunological challenges and opportunities of UTx affecting mother, pregnancy and healthy livebirths.

Adoptive Transfer of Regulatory Immune Cells in Organ Transplantation

Chronic graft rejection remains a significant barrier to solid organ transplantation as a treatment for end-organ failure. Patients receiving organ transplants typically require systemic immunosuppression in the form of pharmacological immunosuppressants for the duration of their lives, leaving these patients vulnerable to opportunistic infections, malignancies, and other use-restricting side-effects. In recent years, a substantial amount of research has focused on the use of cell-based therapies for the induction of graft tolerance. Inducing or adoptively transferring regulatory cell types, including regulatory T cells, myeloid-derived suppressor cells, and IL-10 secreting B cells, has the potential to produce graft-specific tolerance in transplant recipients. Significant progress has been made in the optimization of these cell-based therapeutic strategies as our understanding of their underlying mechanisms increases and new immunoengineering technologies become more widely available. Still, many questions remain to be answered regarding optimal cell types to use, appropriate dosage and timing, and adjuvant therapies. In this review, we summarize what is known about the cellular mechanisms that underly the current cell-based therapies being developed for the prevention of allograft rejection, the different strategies being explored to optimize these therapies, and all of the completed and ongoing clinical trials involving these therapies.

Antigen-Specific Treatment Modalities in MS: The Past, the Present, and the Future

Antigen-specific therapy for multiple sclerosis may lead to a more effective therapy by induction of tolerance to a wide range of myelin-derived antigens without hampering the normal surveillance and effector function of the immune system. Numerous attempts to restore tolerance toward myelin-derived antigens have been made over the past decades, both in animal models of multiple sclerosis and in clinical trials for multiple sclerosis patients. In this review, we will give an overview of the current approaches for antigen-specific therapy that are in clinical development for multiple sclerosis as well provide an insight into the challenges for future antigen-specific treatment strategies for multiple sclerosis.

Addressing resistance to immune checkpoint inhibitor therapy: an urgent unmet need

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of various cancers by reversing the immunosuppressive mechanisms employed by tumors to restore anticancer immunity. Although ICIs have demonstrated substantial clinical efficacy, patient response can vary in depth and duration, and many do not respond at all or eventually develop resistance. ICI resistance mechanisms can be tumor-intrinsic, related to the tumor microenvironment or patient-specific factors. Multiple resistance mechanisms may be present within one tumor subtype, or heterogeneity exists among patients with the same tumor type. Consequently, designing effective combination treatment strategies is challenging. This review will discuss ICI resistance mechanisms, and summarize findings from key preclinical and clinical trials of ICIs, to identify potential treatment strategies or pathways to overcome ICI resistance.

Potential predictive value of change in inflammatory cytokines levels subsequent to initiation of immune checkpoint inhibitor in patients with advanced non-small cell lung cancer

For a definite indication for immunotherapy, finding appropriate biomarkers that are predictive of treatment responses is necessary. Inflammatory cytokines which play critical roles in immunity against infectious sources or cancer cells are suggested to activate immune cells after initiation of immune checkpoint inhibitors (ICI). Through activation of immune cells such as T cells, natural killer cells, macrophages, or tumor infiltrating dendritic cells, inflammatory cytokines usually increase after programmed death (PD)-1/PD-L1 axis blockade. There have been several studies evaluating the predictive value of early changes in inflammatory cytokines in non-small cell lung cancer (NSCLC) patients undergoing immunotherapy. In this mini-review, we went through recent articles on potential blood level values of inflammatory cytokines in NSCLC patients receiving ICI and their early change around commencement of ICIs in predicting response to treatment and disease progression. The studies evaluated cytokines including interleukin (IL)-2, 6, 8, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α for predictability for responses to ICI. A combination cytokine panel can help predict the response and prognosis of patients with NSCLC who are receiving ICI treatment. Furthermore, a more individualized ICI treatment will be available if responses and change in tumor burden can be predicted. However, most of the studies on cytokines in NSCLC patients receiving ICIs had a small number of patients, and the heterogeneous measurement time points. Nevertheless, cytokines such as IL-8 and IFN- γ have considerable potential predictive value for immunotherapy response, which is worthy of further studies. To utilize blood cytokines levels as biomarkers for immunotherapy, a larger study with uniform measurement protocol is necessary.

Mechanisms of resistance to immune checkpoint inhibitors and strategies to reverse drug resistance in lung cancer

In recent years, the research of immune checkpoint inhibitors has made a great breakthrough in lung cancer treatment. Currently, a variety of immune checkpoint inhibitors have been applied into clinical practice, including antibodies targeting the programmed cell death-1, programmed cell death-ligand 1, and cytotoxic T-lymphocyte antigen 4, and so on. However, not all patients can benefit from the treatment. Abnormal antigen presentation, functional gene mutation, tumor microenvironment, and other factors can lead to primary or secondary resistance. In this paper, we reviewed the molecular mechanism of immune checkpoint inhibitor resistance and various combination strategies to overcome resistance, in order to expand the beneficial population and enable precision medicine.

The Resistance Mechanisms of Lung Cancer Immunotherapy

Immunotherapy has revolutionized lung cancer treatment in the past decade. By reactivating the host’s immune system, immunotherapy significantly prolongs survival in some advanced lung cancer patients. However, resistance to immunotherapy is frequent, which manifests as a lack of initial response or clinical benefit to therapy (primary resistance) or tumor progression after the initial period of response (acquired resistance). Overcoming immunotherapy resistance is challenging owing to the complex and dynamic interplay among malignant cells and the defense system. This review aims to discuss the mechanisms that drive immunotherapy resistance and the innovative strategies implemented to overcome it in lung cancer.

Antigen-Specific Immunotherapy for Treatment of Autoimmune Liver Diseases

The liver is a critical organ in controlling immune tolerance. In particular, it is now clear that targeting antigens for presentation by antigen presenting cells in the liver can induce immune tolerance to either autoantigens from the liver itself or tissues outside of the liver. Here we review immune mechanisms active within the liver that contribute both to the control of infectious diseases and tolerance to self-antigens. Despite its extraordinary capacity for tolerance induction, the liver remains a target organ for autoimmune diseases. In this review, we compare and contrast known autoimmune diseases of the liver. Currently patients tend to receive strong immunosuppressive treatments and, in many cases, these treatments are associated with deleterious side effects, including a significantly higher risk of infection and associated health complications. We propose that, in future, antigen-specific immunotherapies are adopted for treatment of liver autoimmune diseases in order to avoid such adverse effects. We describe various therapeutic approaches that either are in or close to the clinic, highlight their mechanism of action and assess their suitability for treatment of autoimmune liver diseases.

Current advances in PD-1/PD-L1 axis-related tumour-infiltrating immune cells and therapeutic regimens in glioblastoma

Glioblastoma (GBM) is the most common malignant tumour in the brain, and current treatments are not curative and cannot control recurrence. This limitation indirectly places immunotherapy at the focus of translational GBM research. Many studies on the PD-1/PD-L1 axis in GBM are ongoing, and the immunosuppressive mechanism of PD-1/PD-L1 in GBM is different from that in other solid tumours. This review focuses on the effect of the PD-1/PD-L1 axis on infiltrating immune cells in the suppressive GBM immune microenvironment and summarizes the recent progress in PD-1/PD-L1 axis-related therapies reported in preclinical and clinical GBM studies, providing a reference for the systematic study of PD-1/PD-L1 axis-related anti-GBM immunity.

The inhibitory activity of alginate against allergic reactions in an ovalbumin-induced mouse model

Marine seaweed polysaccharides have been considered as a potential resource for antiallergic therapy. Alginate is an acidic linear polysaccharide and soluble dietary fiber that was extracted from brown algae, Laminaria japonica. The molecular weight of alginate was 108 kDa, and its water solution exhibited non-Newtonian characteristics, including viscoelasticity and shear-thinning behavior. The ability of alginate to inhibit allergic reactions was investigated in ovalbumin (OVA)-induced BALB/c mice, which have been widely used as a mouse model of egg allergy. The results showed that alginate could effectively attenuate the occurrence of allergic reactions, including improving the integrity of the intestinal epithelial villi and inhibition of mast cell degranulation in the jejunum, in OVA-induced mice. Moreover, after treatment with alginate, the levels of IgE, histamine and IL-4 in OVA-induced mice were remarkably decreased, and the levels of IFN-γ were markedly increased. In addition, the number of Treg cells in spleen tissues in OVA-induced mice was increased by alginate, and the OVA-induced differentiation of Th0 cells into Th2 cells was significantly inhibited. These results demonstrate that alginate possesses potential antiallergic activities in a mouse model of egg allergy, which might provide important evidence that alginate, extracted from Laminaria japonica, can be developed into a novel functional food for inhibiting egg allergy.

Mechanisms of Resistance to Checkpoint Blockade Therapy

Immune checkpoint blockades (ICBs), as a major breakthrough in cancer immunotherapy, target CTLA-4 and the PD-1/PD-L1 axis and reinvigorate anti-tumor activities by disrupting co-inhibitory T-cell signaling. With unprecedented performance in clinical trials, ICBs have been approved by FDA for the treatment of malignancies such as melanoma, non-small-cell lung cancer, colorectal cancer, and hepatocellular carcinoma. However, while ICBs are revolutionizing therapeutic algorithms for cancers, the frequently observed innate, adaptive or acquired drug resistance remains an inevitable obstacle to a durable antitumor activity, thus leading to non-response or tumor relapse. Researches have shown that resistance could occur at each stage of the tumor's immune responses. From the current understanding, the molecular mechanisms for the resistance of ICB can be categorized into the following aspects: 1. Tumor-derived mechanism, 2. T cell-based mechanism, and 3. Tumor microenvironment-determined resistance. In order to overcome resistance, potential therapeutic strategies include enhancing antigen procession and presentation, reinforcing the activity and infiltration of T cells, and destroying immunosuppression microenvironment. In future, determining the driving factors behind ICB resistance by tools of precision medicine may maximize clinical benefits from ICBs. Moreover, efforts in individualized dosing, intermittent administration and/or combinatory regimens have opened new directions for overcoming ICB resistance.

Oncolytic Newcastle disease virus expressing a checkpoint inhibitor as a radioenhancing agent for murine melanoma

BACKGROUND

Monoclonal antibodies (mAbs) targeting negative regulators, or checkpoint molecules (e.g. PD1/PD-L1 & CTLA4), of anti-tumoural T cells have demonstrated clinical efficacy in treating several neoplastic diseases. While many patients enjoy remarkable responses to checkpoint inhibitors, a majority show adverse effects. Understanding how checkpoint inhibitors may augment established chemotherapy or radiotherapy regimens or other immunotherapies like oncolytic viruses may lead to better clinical outcomes measured by improved efficacy with reduced toxicity. Here, we assess how Newcastle disease virus (NDV), an oncolytic virus in clinical testing, may interact with radiotherapy to enhance checkpoint inhibitor blockade.

METHODS

An immunocompetent B16-F10 murine melanoma model, generally considered to be a poorly immunogenic or "cold" tumour, was utilised to query whether combining localised radiotherapy with NDV may be more effective than either therapy alone in controlling tumours in mice treated with anti-PD1 or anti-CTLA4 monoclonal antibodies. We also investigated whether localised administration of a checkpoint inhibitor through an intratumoural injection of NDV that expresses anti-CTLA4 single-chain variable fragment (scFv) is comparable to systemic administration of anti-CTLA4 when combined with radiation in mediating its anti-tumour efficacy. Response rates were characterised by measuring tumour size over time, observation of complete tumour regression, and overall survival.

FINDINGS

Our results show that combining NDV plus radiotherapy with checkpoint inhibitors (PD1 or CTLA4 targeted mAbs) results in significantly better complete tumour regression rates with an abscopal effect in a murine model of melanoma than either single therapy combined with checkpoint inhibitors. Finally, we also show that localised administration of a recombinant NDV expressing anti-CTLA4 plus radiation is comparable to systemic anti-CTLA4 plus radiation in mediating its anti-tumour effect as assayed by survival benefit.

INTERPRETATION

Our results show that oncolytic NDV plus radiotherapy work together with checkpoint inhibitors to enhance tumour clearance of murine melanoma. NDV is an effective radiotherapy dose-sparing and immunotherapeutic agent capable of transgenic, in vivo expression of an anti-CTLA4 targeted scFv antibody with the potential to spare systemic exposure.

FUNDING

The National Institutes of Health grant HHSN272201400008C supported the work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

The Cancer Immunogram as a Framework for Personalized Immunotherapy in Urothelial Cancer

CONTEXT

The abysmal outlook of urothelial cancer (UC) has changed with the introduction of immunotherapy. Still, many patients do not respond and distinctive biomarkers are currently lacking. The rise of this novel armamentarium of immunotherapy treatments, in combination with the complex biology of an immunological tumor response, warrants the development of a comprehensive framework that can provide an overview of important immunological processes at play in individual patients.

OBJECTIVE

To develop a comprehensive framework based on tumor- and host-specific parameters to understand immunotherapy response in UC. This framework can inform rational, biology-driven clinical trials and ultimately guide us toward individualized patient treatment.

EVIDENCE ACQUISITION

A literature review was conducted on UC immunotherapy, clinical trial data, and biomarkers of response to checkpoint inhibition.

EVIDENCE SYNTHESIS

Here, we propose a UC immunogram, based on currently available clinical and translational data. The UC immunogram describes several tumor- and host-specific parameters that are required for successful immunotherapy treatment. These seven parameters are tumor foreignness, immune cell infiltration, absence of inhibitory checkpoints, general performance and immune status, absence of soluble inhibitors, absence of inhibitory tumor metabolism, and tumor sensitivity to immune effectors.

CONCLUSIONS

Longitudinal integration of individual patient parameters may ultimately lead to personalized and dynamic immunotherapy, to adjust to the Darwinian forces that drive tumor evolution. Incorporating multiparameter biomarkers into quantitative predictive models will be a key challenge to integrate the immunogram into daily clinical practice.

PATIENT SUMMARY

Here, we propose the urothelial cancer immunogram, a novel way of describing important immunological characteristics of urothelial cancer patients and their tumors. Seven characteristics determine the chance of having an immunological tumor response. Using this immunogram, we aim to better understand why some patients respond to immunotherapy and some do not, to ultimately improve anticancer therapy.

Immunotherapy With Apitopes Blocks the Immune Response to TSH Receptor in HLA-DR Transgenic Mice

We have combined major histocompatibility complex-binding assays with immunization and tolerance induction experiments in HLA-DR3 transgenic mice to design apitopes (antigen-processing independent epitopes) derived from thyrotropin receptor (TSHR) for treatment of patients with Graves' disease (GD). A challenge model was created by using an adenovirus-expressing part of the extracellular domain of the thyrotropin receptor (TSHR289). This model was used to test whether current drug treatments for GD would have an impact on effective antigen-specific immunotherapy using the apitope approach. Furthermore, selected peptides were assessed for their antigenicity using peripheral blood mononuclear cell samples from patients with GD. A mixture of two immunodominant apitopes was sufficient to suppress both the T-cell and antibody response to TSHR when administered in soluble form to HLA-DR transgenic mice. Tolerance induction was not disrupted by current drug treatments. These results demonstrate that antigen-specific immunotherapy with apitopes from TSHR is a suitable approach for treatment of GD.

Induction of bystander tolerance and immune deviation after Fel d 1 peptide immunotherapy

BACKGROUND

Treatment of patients with cat allergy with peptides derived from Fel d 1 (the major cat allergen) ameliorated symptoms of cat allergy in phase 2 clinical trials.

OBJECTIVE

We sought to demonstrate that the tolerance induced by Fel d 1 peptide immunotherapy can be exploited to reduce allergic responses to a second allergen, ovalbumin (OVA), in mice sensitized dually to OVA and Fel d 1.

METHODS

Induction of tolerance to OVA was achieved through simultaneous exposure to both allergens after peptide treatment. Functional tolerance to each allergen was assessed in a model of allergic airways disease in which treated mice were protected from eosinophilia, goblet cell hyperplasia, and T_H2 cell infiltration.

RESULTS

Suppression of allergic responses to cat allergen challenge was associated with significant increases in numbers of CD4⁺CD25⁺Foxp3⁺ T cells, IL-10⁺ cells, and CD19⁺IL-10⁺ B cells, whereas the response to OVA was associated with a marked reduction in numbers of T_H2 cytokine-secreting T cells and less prominent changes in outcomes associated with immune regulation.

CONCLUSIONS

These observations suggest that immune tolerance induced by peptide immunotherapy can be used experimentally to treat an allergic response to another allergen and that the molecular mechanisms underlying induction of tolerance to a treatment-specific allergen and a bystander allergen might be different.

The Gut Microbiome and Multiple Sclerosis

The microbiome can be defined as the sum of the microbial and host's genome. Recent information regarding this complex organ suggests that in animal models of multiple sclerosis (MS), the composition of the gut microbiome can be altered, giving rise to both the effector and regulatory phases of central nervous system (CNS) demyelination. Experimental findings during the past decade in animal models of MS have provided clear evidence for the significant role of gut microbes in both the effector and regulatory phase of this condition. There is mounting evidence in preliminary human studies suggesting that a dysbiotic MS gut microbiome could affect disease progression. We propose considering the gut microbiome as a key organ for the regulation of tolerance mechanisms and speculate that the gut microbiome is the major environmental risk factor for CNS demyelinating disease. Accordingly, we hypothesize that intervention of the gut microbiome could result in safer novel therapeutic strategies to treat MS.

ATX-MS-1467 Induces Long-Term Tolerance to Myelin Basic Protein in (DR2 × Ob1)F1 Mice by Induction of IL-10-Secreting iTregs

Introduction

Antigen-specific immunotherapy could provide a targeted approach for the treatment of multiple sclerosis that removes the need for broad-acting immunomodulatory drugs. ATX-MS-1467 is a mixture of four peptides identified as the main immune-dominant disease-associated T-cell epitopes in myelin basic protein (MBP), an autoimmune target for activated autoreactive T cells in multiple sclerosis. Previous animal studies have shown that ATX-MS-1467 treatment prevented the worsening of signs of disease in experimental autoimmune encephalitis (EAE) in the humanized (DR2 × Ob1)F1 mouse in a dose-dependent fashion.

Methods and Results

Our study extends these observations to show that subcutaneous treatment with 100 µg of ATX-MS-1467 after induction of EAE in the same mouse model reversed established clinical disability (p < 0.0001) and histological markers of inflammation and demyelination (p < 0.001) compared with vehicle-treated animals; furthermore, in longitudinal magnetic resonance imaging analyses, disruption of blood–brain barrier integrity was reversed, compared with vehicle-treated animals (p < 0.05). Chronic treatment with ATX-MS-1467 was associated with an enduring shift from a pro-inflammatory to a tolerogenic state in the periphery, as shown by an increase in interleukin 10 secretion, relative to interleukin 2, interleukin 17 and interferon γ, a decrease in splenocyte proliferation and an increase in interleukin 10⁺ Foxp3⁻ T cells in the spleen.

Conclusion

Our results suggest that ATX-MS-1467 can induce splenic iTregs and long-term tolerance to MBP with the potential to partially reverse the pathology of multiple sclerosis, particularly during the early stages of the disease.

Funding

EMD Serono, Inc., a business of Merck KGaA.

Dysfunctional immunoregulation in human liver allograft rejection associated with compromised galectin-1/CD7 pathway function

Regulatory T cells in rejected allograft patients display an inability to control responder T cells. Galectin-1 (Gal1) inhibits responder T cells through binding CD7. We investigated whether the dysfunctional immunoregulation in liver allograft rejection patients results from reduced regulatory T-cell Gal1 expression and/or responder T-cell CD7 expression. Circulating regulatory T cells and responder T cells were profiled from 31 acute rejection transplant patients, 85 transplant patients in remission, and 40 healthy controls. CD7+ and CD7− responder T cells were co-cultured with regulatory T cells to assess regulatory T-cell suppressor function. Gal1-small interfering RNA was used to silence regulatory T-cell Gal1. The CD7+ cell percentage was inversely correlated with AST, ALT, and GGT levels. The proportions of CD7+ responder T cells and Gal1+ regulatory T cells were higher in healthy controls than in transplant patients in remission and lowest in acute rejection transplant patients. Notably, CD7+ responder T-cell susceptibility to Gal1+ regulatory T-cell control was ranked in the same manner. Silencing Gal1 expression in regulatory T cells reduced their ability to suppress CD7+ (but not CD7−) responder T cells. Additionally, the proportions of CD43+ and CD45+ responder T cells were higher in healthy controls than in acute rejection transplant patients. CD43 co-expression (but not CD45 co-expression) on CD7+ responder T cells promoted their apoptosis in a Gal1-dependent manner. In sum, dysfunctional immunoregulation in liver allograft rejection patients can be partly attributed to reduced regulatory T-cell Gal1 expression and reduced responder T-cell CD7 expression. Responder T-cell CD43 downregulation in acute rejection patients may further contribute to reduced responder T-cell responsiveness to regulatory T-cell control.

Regulation of PD-1/PD-L1 pathway and resistance to PD-1/PD-L1 blockade

Immune checkpoint blockades, such as inhibitors against programmed death 1 (PD-1) and its ligand (PD-L1), have received extensive attention in the past decade because of their dramatic clinical outcomes in advanced malignancies. However, both primary and acquired resistance becomes one of the major obstacles, which greatly limits the long-lasting effects and wide application of PD-1/PD-L1 blockade therapy. PD-1/PD-L1 both regulates and is regulated by cellular signaling pathways and epigenetic modification, thus inhibiting the proliferation and effector function of T and B cells. The lack of tumor antigens and effective antigen presentation, aberrant activation of oncogenic pathways, mutations in IFN-γ signaling, immunosuppressive tumor microenvironment such as regulatory T cells, myeloid-derived suppressor cells, M2 macrophages, and immunoinhibitory cytokines can lead to resistance to PD-1/PD-L1 blockade. In this review, we describe PD-1 related signaling pathways, essential factors contributing to the resistance of PD-1 blockade, and discuss strategies to increase the efficacy of immunotherapy. Furthermore, we discuss the possibility of combined epigenetic therapy with PD-1 blockade as a potential promising approach for cancer treatment.

A Novel Approach to Reinstating Tolerance in Experimental Autoimmune Myasthenia Gravis Using a Targeted Fusion Protein, mCTA1-T146

Reinstating tissue-specific tolerance has attracted much attention as a means to treat autoimmune diseases. However, despite promising results in rodent models of autoimmune diseases, no established tolerogenic therapy is clinically available yet. In the experimental autoimmune myasthenia gravis (EAMG) model several protocols have been reported that induce tolerance against the prime disease-associated antigen, the acetylcholine receptor (AChR) at the neuromuscular junction. Using the whole AChR, the extracellular part or peptides derived from the receptor, investigators have reported variable success with their treatments, though, usually relatively large amounts of antigen has been required. Hence, there is a need for better formulations and strategies to improve on the efficacy of the tolerance-inducing therapies. Here, we report on a novel targeted fusion protein carrying the immunodominant peptide from AChR, mCTA1–T146, which given intranasally in repeated microgram doses strongly suppressed induction as well as ongoing EAMG disease in mice. The results corroborate our previous findings, using the same fusion protein approach, in the collagen-induced arthritis model showing dramatic suppressive effects on Th1 and Th17 autoaggressive CD4 T cells and upregulated regulatory T cell activities with enhanced IL10 production. A suppressive gene signature with upregulated expression of mRNA for TGFβ, IL10, IL27, and Foxp3 was clearly detectable in lymph node and spleen following intranasal treatment with mCTA1–T146. Amelioration of EAMG disease was accompanied by reduced loss of muscle AChR and lower levels of anti-AChR serum antibodies. We believe this targeted highly effective fusion protein mCTA1–T146 is a promising candidate for clinical evaluation in myasthenia gravis patients.

Primary, Adaptive, and Acquired Resistance to Cancer Immunotherapy

Cancer immunotherapy can induce long lasting responses in patients with metastatic cancers of a wide range of histologies. Broadening the clinical applicability of these treatments requires an improved understanding of the mechanisms limiting cancer immunotherapy. The interactions between the immune system and cancer cells are continuous, dynamic, and evolving from the initial establishment of a cancer cell to the development of metastatic disease, which is dependent on immune evasion. As the molecular mechanisms of resistance to immunotherapy are elucidated, actionable strategies to prevent or treat them may be derived to improve clinical outcomes for patients.

Protein kinase C theta is required for efficient induction of IL-10-secreting T cells

Secretion of interleukin-10 (IL-10) by CD4+ T cells is an essential immunoregulatory mechanism. The work presented here assesses the role of the signaling molecule protein kinase C theta (PKCθ) in the induction of IL-10 expression in CD4+ T cells. Using wildtype and PKCθ-deficient Tg4 T cell receptor transgenic mice, we implemented a well-described protocol of repeated doses of myelin basic protein (MBP)Ac1-9[4Y] antigen to induce Tr1-like IL-10+ T cells. We find that PKCθ is required for the efficient induction of IL-10 following antigen administration. Both serum concentrations of IL-10 and the proportion of IL-10+ T cells were reduced in PKCθ-deficient mice relative to wildtype mice following [4Y] treatment. We further characterized the T cells of [4Y] treated PKCθ-deficient Tg4 mice and found reduced expression of the transcription factors cMaf, Nfil3 and FoxP3 and the surface receptors PD-1 and Tim3, all of which have been associated with the differentiation or function of IL-10+ T cells. Finally, we demonstrated that, unlike [4Y] treated wildtype Tg4 T cells, cells from PKCθ-deficient mice were unable to suppress the priming of naïve T cells in vitro and in vivo. In summary, we present data demonstrating a role for PKCθ in the induction of suppressive, IL-10-secreting T cells induced in TCR-transgenic mice following chronic antigen administration. This should be considered when contemplating PKCθ as a suitable drug target for inducing immune suppression and graft tolerance.

The influence of gut-derived CD39 regulatory T cells in CNS demyelinating disease

There is considerable interest in trying to understand the importance of the gut microbiome in human diseases. The association between dysbiosis, an altered microbial composition, as related to human disease is being explored in the context of different autoimmune conditions, including multiple sclerosis (MS). Recent studies suggest that MS affects the composition of the gut microbiota by altering the relative abundances of specific bacteria and archaea species. Remarkably, some of the bacterial species shown reduced in the gut of MS patients are known to promote immunosuppressive regulatory T cells (Tregs). In MS, the function of a phenotype of Tregs that express CD39, an ectoenzyme involved in the catabolism of adenosine triphosphate as immunomodulatory cells, appears to be reduced. In this review, we discuss the involvement of the gut microbiota in the regulation of experimental models of central nervous system inflammatory demyelination and review the evidence that link the gut microbiome with MS. Further, we hypothesize that the gut microbiome is an essential organ for the control of tolerance in MS patients and a potential source for safer novel therapeutics.

An imbalance between innate and adaptive immune cells at the maternal-fetal interface occurs prior to endotoxin-induced preterm birth

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. A transition from an anti-inflammatory state to a pro-inflammatory state in the mother and at the maternal-fetal interface has been implicated in the pathophysiology of microbial-induced preterm labor. However, it is unclear which immune cells mediate this transition. We hypothesized that an imbalance between innate and adaptive immune cells at the maternal-fetal interface will occur prior to microbial-induced preterm labor. Using an established murine model of endotoxin-induced PTB, our results demonstrate that prior to delivery there is a reduction of CD4+ regulatory T cells (Tregs) in the uterine tissues. This reduction is neither linked to a diminished number of Tregs in the spleen, nor to an impaired production of IL10, CCL17, or CCL22 by the uterine tissues. Endotoxin administration to pregnant mice does not alter effector CD4+ T cells at the maternal-fetal interface. However, it causes an imbalance between Tregs (CD4+ and CD8+), effector CD8+ T cells, and Th17 cells in the spleen. In addition, endotoxin administration to pregnant mice leads to an excessive production of CCL2, CCL3, CCL17, and CCL22 by the uterine tissues as well as abundant neutrophils. This imbalance in the uterine microenvironment is accompanied by scarce APC-like cells such as macrophages and MHC II+ neutrophils. Collectively, these results demonstrate that endotoxin administration to pregnant mice causes an imbalance between innate and adaptive immune cells at the maternal-fetal interface.

Immunopathogenesis of Hepatitis C Virus Infection

Despite advances in therapy, hepatitis C virus infection remains a major global health issue with 3 to 4 million incident cases and 170 million prevalent chronic infections. Complex, partially understood, host-virus interactions determine whether an acute infection with hepatitis C resolves, as occurs in approximately 30% of cases, or generates a persistent hepatic infection, as occurs in the remainder. Once chronic infection is established, the velocity of hepatocyte injury and resultant fibrosis is significantly modulated by immunologic as well as environmental factors. Immunomodulation has been the backbone of antiviral therapy despite poor understanding of its mechanism of action.

Impairment of dendritic cell function and induction of CD4(+)CD25(+)Foxp3(+) T cells by excretory-secretory products: a potential mechanism of immune evasion adopted by Echinococcus granulosus

Background

Cystic echinococcosis, caused by infection with Echinococcus granulosus, is one of the most widespread zoonotic helminth diseases. Modulation of host responses is an important strategy used by helminth parasites to promote infection. To better understand the mechanisms adopted by E. granulosus to escape host immune responses, we investigated the effects of excretory–secretory products (ES) and adult worm antigen (AWA) derived from adult E. granulosus on murine bone marrow-derived dendritic cells (BMDC).

Results

Compared with lipopolysaccharide (LPS), AWA, but not ES, induced BMDC maturation or stimulated BMDC cytokine production and co-stimulatory molecule expression (CD40, CD80 and MHC class II). Furthermore, ES-treated BMDCs pulsed with ovalbumin exhibited reduced co-stimulatory molecule expression in comparison with untreated BMDC, even in the presence of the strong Th1 inducer, CpG. Moreover, we detected the effects of ES-treated DC on T cell activation by an in vitro T cell priming assay. We observed that ES-treated BMDC co-cultured with DO11.10 transgenic CD4⁺ T cells induced the generation of CD4⁺CD25⁺Foxp3⁺ T cells. In addition, in contrast to AWA-treated BMDCs, which had markedly induced IFN-γ secretion and reduced of IL-4 levels in co-cultured T cells, ES-treated BMDCs did not modify their capacity to stimulate IFN-γ or IL-4 production by T cells.

Conclusions

We conclude that ES of adult E. granulosus inhibited DC function, impaired the development of Th1 cells induced by CpG, and induced CD4⁺CD25⁺Foxp3⁺ regulatory T cells in an IL-10-independent manner.

Preclinical development and first-in-human study of ATX-MS-1467 for immunotherapy of MS

OBJECTIVE

The study was designed to test the efficacy of ATX-MS-1467 in a relevant preclinical model and to assess its safety for the treatment of patients with secondary progressive multiple sclerosis (SPMS).

METHODS

ATX-MS-1467 was tested for its ability to suppress experimental autoimmune encephalomyelitis (EAE) in the (Ob x DR2)F1 mouse both before and after disease onset. Safety was assessed by clinical assessment, MRI analysis, and the measurement of immune responses to self- and nonself-antigens in patients with SPMS.

RESULTS

ATX-MS-1467 displayed a dose-dependent inhibition of EAE and was more effective than glatiramer acetate in the treatment of ongoing disease in humanized mice. A phase 1 open-label dose-escalating study demonstrated that ATX-MS-1467 was safe and well-tolerated in a group of 6 patients with SPMS, up to a dose of 800 µg.

CONCLUSIONS

The results of this study support further development of ATX-MS-1467 in a clinical trial powered to investigate the immunologic and clinical benefits of treatment in relapsing-remitting MS.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that ATX-MS-1467 is safe and tolerated in a group of 6 patients with SPMS.

Mechanisms of immunological tolerance in central nervous system inflammatory demyelination

Multiple sclerosis is a complex autoimmune disease of the central nervous system that results in a disruption of the balance between pro-inflammatory and anti-inflammatory signals in the immune system. Given that central nervous system inflammation can be suppressed by various immunological tolerance mechanisms, immune tolerance has become a focus of research in the attempt to induce long-lasting immune suppression of pathogenic T cells. Mechanisms underlying this tolerance induction include induction of regulatory T cell populations, anergy and the induction of tolerogenic antigen-presenting cells. The intravenous administration of encephalitogenic peptides has been shown to suppress experimental autoimmune encephalomyelitis and induce tolerance by promoting the generation of regulatory T cells and inducing apoptosis of pathogenic T cells. Safe and effective methods of inducing long-lasting immune tolerance are essential for the treatment of multiple sclerosis. By exploring tolerogenic mechanisms, new strategies can be devised to strengthen the regulatory, anti-inflammatory cell populations thereby weakening the pathogenic, pro-inflammatory cell populations.

Sequential transcriptional changes dictate safe and effective antigen-specific immunotherapy

Antigen-specific immunotherapy combats autoimmunity or allergy by reinstating immunological tolerance to target antigens without compromising immune function. Optimization of dosing strategy is critical for effective modulation of pathogenic CD4⁺ T-cell activity. Here we report that dose escalation is imperative for safe, subcutaneous delivery of the high self-antigen doses required for effective tolerance induction and elicits anergic, interleukin (IL)-10-secreting regulatory CD4⁺ T cells. Analysis of the CD4⁺ T-cell transcriptome, at consecutive stages of escalating dose immunotherapy, reveals progressive suppression of transcripts positively regulating inflammatory effector function and repression of cell cycle pathways. We identify transcription factors, c-Maf and NFIL3, and negative co-stimulatory molecules, LAG-3, TIGIT, PD-1 and TIM-3, which characterize this regulatory CD4⁺ T-cell population and whose expression correlates with the immunoregulatory cytokine IL-10. These results provide a rationale for dose escalation in T-cell-directed immunotherapy and reveal novel immunological and transcriptional signatures as surrogate markers of successful immunotherapy.

Dose escalation in antigen-specific therapies is recognized as safe and effective, but the underlying effects of dosing variables on the immune system are not understood. Here, the authors demonstrate that dose escalation causes sequential modulation of gene expression among antigen-specific lymphocytes.

Harnessing FOXP3+ regulatory T cells for transplantation tolerance

Early demonstrations that mice could be tolerized to transplanted tissues with short courses of immunosuppressive therapy and that with regard to tolerance to self, CD4+FOXP3+ regulatory T cells (Tregs) appeared to play a critical role, have catalyzed strategies to harness FOXP3-dependent processes to control rejection in human transplantation. This review seeks to examine the scientific underpinning for this new approach to finesse immunosuppression.

Therapeutic potential of regulatory T cells in autoimmune disorders

Regulatory T cells (Tregs) play a dominant role in the regulation of immune responses. Quantitative and/or qualitative abnormalities of Tregs were observed in patients with autoimmune diseases and therapeutic interventions focusing Tregs are an attractive new target with the potential to cure these disorders. Biological agents approved for treatment of inflammatory rheumatic diseases transiently influence Treg prevalences and function and experimental therapies including novel biological agents, gene therapy, activation and ex vivo expansion of purified Tregs as well as substances influencing tolerogenic dendritic cells will be developed for selective Treg therapy. Although many of these interventions are effective in vitro, in animal models as well as in early clinical trials, significant concerns exist regarding the stability of Treg modifications as well as the long-term safety of Treg-based therapies.

Changes of regulatory T cells in Graves' disease

The immune mechanism of Graves' diseases (GD) and the roles of regulator T cells were investigated. In 32 patients with GD (GD group) and 20 healthy volunteers (control group), flow cytometry was used to detect the proportion of CD4+CD25+ cells, MACS to isolate CD4+ CD25+ cells, RT-PCR to assay the expression of FOXP3, and ELISA to test the level of IL-10, respectively. It was found that there was no significant change in the proportion of CD4+CD25+ T cells between GD group and control group (P>0.05), while secretion of IL-10 and expression of FOXP3 in GD group were lower than control group (P<0.01 and P<0.05, respectively). In conclusion, though the proportion of regulatory T cells of peripheral blood lymphocytes in the patients with GD, the functions of them were significantly weakened, which might be a pathogenic factor in GD.