Biomaterial implants are a critical aspect of our medical therapies and biomedical research and come in various forms: stents, implantable glucose sensors, orthopedic implants, silicone implants, drug delivery systems, and tissue engineered scaffolds. Their implantation triggers a series of biological responses that often times lead to the foreign body response and subsequent fibrotic encapsulation, a dense ECM-rich capsule that isolates the biomaterial and renders it ineffective. These responses lead to the failure of biomaterials and is a major hurdle to overcome and in promoting their success. Much attention has been given to macrophage populations for the inflammatory component of these responses to biomaterials but recent work has identified an important role of T cells and their ability to modulate fibroblast activity and vice versa. In this review, we focus on T cell-fibroblast crosstalk by exploring T cell subsets, critical signaling pathways, and fibroblast populations that have been shown to dictate biomaterial-mediated fibrosis. We then highlight emerging technologies and model systems that enable new insights and avenues to T cell-fibroblast crosstalk that will improve biomaterial outcomes.

Pulmonary fibrosis is an incurable disease that manifests with advanced age. Yet, how hematopoietic aging influences immune responses and fibrosis progression remains unclear. Using heterochronic bone marrow transplant mouse models, we found that an aged bone marrow exacerbates lung fibrosis irrespective of lung tissue age. Upon lung injury, there was an increased accumulation of monocyte-derived alveolar macrophages (Mo-AMs) driven by cell-intrinsic hematopoietic aging. These Mo-AMs exhibited an enhanced profibrotic profile and stalled maturation into a homeostatic, tissue-resident phenotype. This delay was shaped by cell-extrinsic environmental signals such as reduced pulmonary interleukin-10 (IL-10), perpetuating a profibrotic macrophage state. We identified regulatory T cells (Tregs) as critical providers of IL-10 upon lung injury that promote Mo-AM maturation and attenuate fibrosis progression. Our study highlights the impact of an aging bone marrow on lung immune regulation and identifies Treg-mediated IL-10 signaling as a promising target to mitigate fibrosis and promote tissue repair.

24-Nor-ursodeoxycholic acid (NorUDCA) is a novel therapeutic bile acid for treating immune-mediated cholestatic liver diseases, such as primary sclerosing cholangitis (PSC).

Since PSC strongly associates with T helper-type-like 17 (TH17)-mediated intestinal inflammation, we explored NorUDCA's immunomodulatory potential on TH17 cells.

NorUDCA's impact on TH17 differentiation was assessed using a CD4+TNaive adoptive transfer mouse model, and on intraepithelial TH17 pathogenicity and transdifferentiation using an αCD3 stimulation model combined with interleukin-17A-fate-mapping. Mechanistic studies used molecular and multiomics approaches, flow cytometry and metabolic assays with pathogenic (p) TH17. Pathogenicity of pTH17 exposed to NorUDCA in vitro was evaluated following adoptive transfer in intestinal tissues or the central nervous system (CNS). Key findings were validated in an αCD3-stimulated humanised NSG mouse model reconstituted with peripheral blood mononuclear cells from patients with PSC.

NorUDCA suppressed TH17 effector function and enriched regulatory T cell (Treg) abundance upon CD4+TNaive cell transfer. NorUDCA mitigated intraepithelial TH17 pathogenicity and decreased the generation of proinflammatory 'TH1-like-TH17' cells, and enhanced TH17 transdifferentiation into Treg and Tr1 (regulatory type 1) cells in the αCD3-model. In vivo ablation revealed that Treg induction is crucial for NorUDCA's anti-inflammatory effect on TH17 pathogenicity. Mechanistically, NorUDCA restrained pTH17 effector function and simultaneously promoted functional Treg formation in vitro, by attenuating a glutamine-mTORC1-glycolysis signalling axis. Exposure of pTH17 to NorUDCA dampened their pathogenicity and expansion in the intestine or CNS upon transfer. NorUDCA's impact on TH17 inflammation was corroborated in the humanised NSG mouse model.

NorUDCA restricts TH17 inflammation in multiple mouse models, potentiating future clinical applications for treating TH17-mediated intestinal diseases and beyond.

Preeclampsia (PE) is an obstetrical disorder that occurs after the 20th week of gestation. It is recognized as one of the "Great Obstetrical Syndromes" and principally contributes to maternal morbidity and mortality. PE has been associated with a range of immune disorders, including a preponderance of T helper (Th) 1 over Th2 cells and imbalanced levels of Th17 and T regulatory cells (Tregs). During pregnancy, T cells safeguard the placenta against immune rejection and aid embryo implantation while involved in pregnancy complications, such as PE. Promoting alloantigen-specific Treg cells is a potential preventive and therapeutic strategy for PE. However, ensuring the safety of mothers and infants is of the utmost importance since the risk-benefit ratio of reproductive and obstetric conditions differs significantly from that of immune diseases that pose a life-threatening risk. In this review, we systematically summarize the roles of T-cell immunity in the peripheral blood, reproductive tissues, and at the maternal-fetal interface of PE patients. Furthermore, the recent therapeutic approaches centered on targeting T cell immunity in PE are critically appraised.

Interleukin-10 (IL-10)-producing group 2 innate lymphoid cells (ILC210) regulate inflammatory immune responses, yet their therapeutic potential remains largely unexplored. Here, we demonstrate that cell therapy with human ILC210 inhibits pathogenic T cell responses in humanized mouse models of graft-versus-host disease (GVHD), resulting in reduced GVHD severity and improved overall survival without limiting the graft-versus-leukemia effect. ILC210 conferred superior protection from GVHD than IL-10-/low ILC2s, and blocking IL-10 and IL-4 abrogated ILC210 protective effects, indicating that these cytokines are important for the protective effects of ILC210. Notably, ILC210 provided comparable protection from GVHD to regulatory T cells without impairing T cell engraftment, instead decreasing intestinal T cell infiltration and suppressing CD4+ Th1 and CD8+ Tc1 cells. CITE-seq of expanded ILC2s revealed CD49d and CD86 are markers that allow for enrichment of ILC210 from conventional ILC2s and tracking of ILC210 in patient studies. Altogether, these findings demonstrate the potential of ILC210 in cell therapies for GVHD and other immune-mediated diseases.

In the last decade, advancements in immunotherapy knowledge have highlighted CTLA-4, PD-1, LAG-3, TIM-3, and TIGIT, decisive immune checkpoints exhibiting within the tumor microenvironment (TME), as fundamental objects for cancer immunotherapy. The widespread clinical use of immune checkpoint inhibitors (ICls), employing PD-1/PD-L1 or CTLA-4 antibodies to obstruct crucial checkpoint regulators, is noted in treating B-cell lymphoma patients. Nevertheless, the prolonged advantages of the currently employed treatments against CTLA-4, PD-1, and PD-L1 are uncommon among patients. Thus, recent focus has been progressively moved to additional immune checkpoints on T cells, like LAG-3, TIM-3, and TIGIT, which are now seen as reassuring targets for treatment and broadly acknowledged. There are several types of immunecheckpoint molecules expressed by T cells, and inhibitors targeting immune checkpoints can revive and amplify the immune response of T lymphocytes against tumors, a crucial aspect in lymphoma therapy. However, there is little knowledge about their regulation. Herein, we discuss the anti-tumor effects and functions of ICIs in controlling T-cell activity, as well as the progress in combined application with other immunotherapies.

The association between male infertility and health status has yet to be unraveled. Here, by combining multiparameter phenotyping and scRNA-seq, we delineate the immune status of infertile men both at the semen and systemic levels. We first observe that young infertile men have a pro-inflammatory milieu with increased frequency of myeloid cells and inflammatory mediators in the seminal fluid and the peripheral blood, which are immune alterations typically observed in healthy elderly men. Transcriptomic profiling confirms the upregulation of genes associated with the interferon-gamma and -alpha responses in peripheral blood T cells of infertile men with oligo-astheno-teratozoospermia or non-obstructive azoospermia, with distinct T cell signatures of exhaustion and senescence discriminating the two infertile conditions. These findings provide evidence that subtypes of male infertility are characterized by specific immune signatures and unravel the potential link between infertility and the risk of developing secondary diseases.

Immune checkpoint molecules, including both co-inhibitory molecules and co-stimulatory molecules, are known to play critical roles in regulating T-cell responses. During the last decades, immunotherapies targeting these molecules (such as programmed cell death 1 (PD-1), and lymphocyte activation gene 3 (LAG-3)) have provided clinical benefits in many cancers. It is becoming apparent that not only T cells, but also B cells have a capacity to express some checkpoint molecules. These were originally thought to be only the markers for regulatory B cells which produce IL-10, but recent studies suggest that these molecules (especially T-cell immunoglobulin and mucin domain 1 (TIM-1), T cell immunoreceptor with Ig and ITIM domains (TIGIT), and PD-1) can regulate intrinsic B-cell activation and functions. Here, we focus on these molecules and summarize their characteristics, ligands, and functions on B cells.

Immunogenicity continues to be a challenge for development and clinical utility of monoclonal antibodies, and there are gaps in our current ability to prevent anti-drug antibody development in a safe and antigen-specific manner.

To mitigate immunogenicity of monoclonal antibodies administered subcutaneously, O-phospho-L-serine (OPLS)-the head group of the tolerance-inducing phospholipid, phosphatidylserine-was investigated as an immunoregulatory adjuvant.

Formulations of adalimumab, trastuzumab or rituximab with OPLS showed reduction in relative immunogenicity in mice compared to vehicle formulations, indicated by reduced anti-drug antibody development and significant reductions in CD138+ plasma cell differentiation in bone marrow. Titer development toward recombinant human hyaluronidase, a dispersion enhancer that was co-formulated with monoclonal antibodies, was similarly reduced. Subcutaneous administration of adalimumab with OPLS resulted in a two-fold increase in expression of type 1 regulatory (Tr1) T cell subset in the spleen. This is consistent with in vitro studies where co-culturing of dendritic cells primed with ovalbumin in the presence and absence of OPLS and antigen specific T-cells induced expression of Tr1 phenotype on live CD4+ T cells.

This adjuvant does not impact immune competence of non-human primates and mice, and repeated administration of the adjuvant does not show renal or hepatic toxicity. Formulation of monoclonal antibodies with the immunoregulatory adjuvant, OPLS, was found to be safe and effective at mitigating immunogenicity.

Autoimmune diseases, characterized by the immune system's attack on the body's own tissues, affect millions of people worldwide. Current treatments, which primarily rely on broad immunosuppression and symptom management, are often associated with significant adverse effects and necessitate lifelong therapy. This review explores the next generation of therapies for immune-mediated diseases, including chimeric antigen receptor (CAR) T cell and regulatory T cell (Treg)-based approaches, which offer the prospect of targeted, durable disease remission. Notably, we highlight the emergence of CD19-targeted CAR T cell therapies, and their ability to drive sustained remission in B cell-mediated autoimmune diseases, suggesting a possible paradigm shift. Further, we discuss the therapeutic potential of Type 1 and FOXP3+ Treg and CAR-Treg cells, which aim to achieve localized immune modulation by targeting their activity to specific tissues or cell types, thereby minimizing the risk of generalized immunosuppression. By examining the latest advances in this rapidly evolving field, we underscore the potential of these innovative cell therapies to address the unmet need for long-term remission and potential tolerance induction in individuals with autoimmune and immune-mediated diseases.

Intricate immune regulation is required at mucosal surfaces to allow tolerance to microbiota and harmless allergens and to prevent overexuberant inflammatory responses to pathogens. The cytokine Interleukin-10 (IL-10) is a key mediator of mucosal immune regulation. While IL-10 can be produced by virtually all cells of the immune system, many of its in vivo functions depend upon its production by regulatory or effector T cell populations and its signalling to macrophages, dendritic cells and specific T cell subsets. In this review, we discuss our current understanding of the role of IL-10 in regulation of immune responses, with a focus on its context-specific roles in intestinal homeostasis, respiratory infection and asthma. We highlight the importance of appropriate production and function of IL-10 for balancing pathogen clearance, control of microbiota and host tissue damage, and that precise modulation of IL-10 functions in vivo could present therapeutic opportunities.

Regulatory T (Treg) cells are crucial for maintaining immune tolerance by suppressing response to self-antigens and harmless antigens to prevent autoimmune diseases and uncontrolled immune responses. Therefore, using Treg cells is considered a therapeutic strategy treating inflammatory diseases. Based on their origin, Treg cells are classified into thymus-derived, peripherally induced, and in vitro induced Treg cells. Our group discovered a novel Treg cell subset, namely, Treg-of-B (Treg/B) cells, generated by culturing CD4+CD25- T cells with B cells, including Peyer's patch B cells, splenic B cells and peritoneal B1a cells, for 3 days. Treg/B cells express CD44, OX40 (CD134), cytotoxic T-lymphocyte-associated antigen-4 (CD152), glucocorticoid-induced tumor necrosis factor receptor family-related protein (CD357), interleukin-10 receptor, lymphocyte activation gene-3 (CD223), inducible co-stimulator (CD278), programmed-death 1 (CD279), tumor necrosis factor receptor II, and high levels of IL-10, but not forkhead box protein P3, similar to type 1 Treg (Tr1) cells. However, unlike Tr1 cells, Treg/B cells do not express CD103, CD226, and latency-associated peptide. Treg/B cells have been applied for the treatment of some murine models of inflammatory diseases, including allergic asthma, inflammatory bowel disease, collagen-induced arthritis, gout, psoriasis and primary biliary cholangitis. This review summarizes the current knowledge of Treg/B cells.

Systemic lupus erythematosus (SLE) represents an autoimmune disorder that affects multiple systems. In the treatment of this condition, the focus primarily revolves around inflammation suppression and immunosuppression. Consequently, targeted therapy has emerged as a prevailing approach. Currently, the quest for highly sensitive and specifically effective targets has gained significant momentum in the context of SLE treatment. Lymphocyte activation gene-3 (LAG-3) stands out as a crucial inhibitory receptor that binds to pMHC-II, thereby effectively dampening autoimmune responses. Fibrinogen-like protein 1 (FGL1) serves as the principal immunosuppressive ligand for LAG-3, and their combined action demonstrates a potent immunosuppressive effect. This intricate mechanism paves the way for potential SLE treatment by targeting LAG-3 with FGL1. This work provides a comprehensive summary of LAG-3's role in the pathogenesis of SLE and elucidates the feasibility of leveraging FGL1 as a therapeutic approach for SLE management. It introduces a novel therapeutic target and opens up new avenues of therapeutic consideration in the clinical context of SLE treatment.

Artemisinin and its derivatives, used as front-line anti-malarial drugs, exhibit anti-inflammatory properties. They were found to suppress the generation and function of Th1 and Th17 cells while promoting the generation of Foxp3 + regulatory T cells (Tregs). However, the specific role of Artemotil (β-arteether) in modulating the generation and functions of CD4 + T cells, particularly Type 1 regulatory T cells (Tr1), remains to be explored. Tr1 cells are one of the key cell types that are essential for regulating inflammatory response through IL-10. In this study, we report that Artemotil selectively promotes generation of Tr1 cells induced by IL-27 by upregulating signature genes of Tr1 cells, such as c-Maf, AhR, prdm1, IRF-1, and Batf, while inhibiting the Th1, Th2, and Th17 cells generation. We found that co-administration of Artemotil with anti-CD3 antibody increases the induction of IL-10 and frequency of Tr1 cells while suppressing Th1 and Th17 cells in vivo. Artemotil suppresses T-cell-induced enteropathy and alleviates the signs of colitis associated with the increased frequencies of Tr1 cells. Taken together, our data suggest that Artemotil provides protection in T-cell-mediated colitis by increasing the expansion of Tr1 cells and inhibiting the generation of Th1 and Th17 cells.

Lymphocyte activation gene 3 (Lag3) is an inhibitory co-receptor expressed on activated T cells and has been proposed to regulate regulatory T (Treg) cell function. However, its precise modality and mechanisms remain elusive. We generated Treg cell-specific Lag3-mutant mouse models and found that Lag3 was essential for Treg cell control of autoimmunity. RNA sequencing analysis revealed that Lag3 mutation altered genes associated with metabolic processes, especially Myc target genes. Myc expression in Lag3-mutant Treg cells was increased to the level seen in conventional T helper (Th)1-type effector cells and directly correlated with their metabolic profiles and in vivo suppressive functions. The phosphatidylinositol 3-kinase (PI3K)-Akt-Rictor pathway was activated in Lag3-mutant Treg cells, and inhibiting PI3K, Rictor, or lactate dehydrogenase A (Ldha), a key Myc target enzyme converting pyruvate to lactate, was sufficient to restore normal metabolism and suppressive function in Lag3-mutant Treg cells. These findings indicate that Lag3 supports Treg cell suppression partly by tuning Myc-dependent metabolic programming.

Integrins are a family of cell surface membrane receptors and play a crucial role in facilitating bidirectional cell signaling. Integrin α2 (ITGA2) is expressed across a range of cell types, including epithelial cells, platelets, megakaryocytes, and fibroblasts, where it functions as a surface marker and it is implicated in the cell movements. The most recent findings have indicated that ITAG2 has the potential to function as a novel regulatory factor in cancer, responsible for driving tumorigenesis, inducing chemoresistance, regulating genomic instability and remodeling tumor microenvironment. Hence, we primarily focus on elucidating the biological function and mechanism of ITGA2 within the digestive tumor microenvironment, while highlighting its prospective utilization as a therapeutic target for cancer therapy.

LAG3 is an immune checkpoint molecule with emerging therapeutic use. Expression of LAG3 is well studied on T cells, but the proportion of LAG3-expressing cells varies greatly by study and its comparative expression between non-T cells is lacking.

This study uses flow cytometry to compare surface LAG3 expression between T cells, NK cells, B cells, pDCs and monocytes of healthy donors. This study also compares three monoclonal LAG3 antibodies to a commonly used polyclonal LAG3 antibody on ex vivo and PHA-blasts from healthy donors and LAG3+ and LAG3- cell lines.

LAG3 was most highly expressed on classical and intermediate monocytes (25 % and 32 %, respectively), while LAG3 expression on B cells, NK cells and iNKT cells was negligible. Notably, the polyclonal antibody stained a higher proportion of all cell types than the monoclonal antibodies, which had similar staining patterns to one another. Further study using LAG3+ and LAG3- cell lines showed greater specificity and similar sensitivity of the monoclonal antibody T47-530 than the polyclonal antibody.

Monocytes may represent an unappreciated source of LAG3 and target of LAG3 checkpoint inhibitors. Furthermore, the discrepancies between monoclonal and polyclonal LAG3 antibodies warrants consideration when designing future studies and interpreting past studies, and may explain discrepancies in the literature.

Dendritic cell (DC) activation and function are underpinned by profound changes in cellular metabolism. Several studies indicate that the ability of DCs to promote tolerance is dependent on catabolic metabolism. Yet the contribution of AMP-activated kinase (AMPK), a central energy sensor promoting catabolism, to DC tolerogenicity remains unknown. Here, we show that AMPK activation renders human monocyte-derived DCs tolerogenic as evidenced by an enhanced ability to drive differentiation of regulatory T cells, a process dependent on increased RALDH activity. This is accompanied by several metabolic changes, including increased breakdown of glycerophospholipids, enhanced mitochondrial fission-dependent fatty acid oxidation, and upregulated glucose catabolism. This metabolic rewiring is functionally important as we found interference with these metabolic processes to reduce to various degrees AMPK-induced RALDH activity as well as the tolerogenic capacity of moDCs. Altogether, our findings reveal a key role for AMPK signaling in shaping DC tolerogenicity and suggest AMPK as a target to direct DC-driven tolerogenic responses in therapeutic settings.

Approximately 70% of individuals allergic to birch pollen (Bet v 1.01 [Bet]) develop a secondary food allergy (e.g., hazelnut: Cor a 1.04 [Cor]), due to allergen cross-reactivity. However, standard immunotherapy for type I allergies often does not improve the food allergy sufficiently. We analyzed the allergen-specific and cross-reactive suppressive capacity of primary human regulatory T cells (Treg) induced by autologous IL-10-modulated dendritic cells (IL-10 DC) in vitro and in vivo.

CD4+ T cells of patients with birch pollen and associated hazelnut allergies were differentiated into Bet-specific or non-specific induced Treg (iTreg). After Bet- or Cor-specific restimulation the phenotype, proliferation, and suppressive capacity of iTreg subsets were analyzed. iTreg function was further investigated in humanized mouse models of airway and intestinal allergy, generated by engraftment of peripheral blood mononuclear cells from allergic donors into immunodeficient animals.

After IL-10 DC priming and allergen-specific restimulation (Bet or Cor), non-specific control iTreg remained anergic, whereas Bet-specific iTreg proliferated extensively and exhibited a regulatory phenotype (enhanced expression of CTLA-4, PD-1, TNFR2, IL-10). Accordingly, activated Bet-specific iTreg displayed a high capacity to suppress Bet- and Cor-induced responder Th2 cell responses in vitro, indicating induction of both allergen-specific (birch) and cross-reactive tolerance (hazelnut). In vivo, the beneficial effect of Bet-specific iTreg was verified in humanized mouse models of allergic airway and intestinal inflammation, resulting in reduced allergen-induced clinical symptoms, and immune responses.

Human IL-10 DC-induced iTreg facilitate allergen-specific and cross-reactive tolerance. Therefore, they are potential candidates for regulatory cell therapy in allergic and autoimmune diseases.

After transplantation of allogeneic tissues and organs, recognition by recipient T cells of donor MHC molecules initiates the pro-inflammatory adaptive immune response leading to allograft rejection. T cell allorecognition has long been known to be mediated via two distinct pathways: the direct pathway in which T cells recognize intact allogeneic MHC molecules displayed on donor cells and the indirect pathway whereby T cells recognize donor MHC peptides processed and presented by recipient antigen-presenting cells (APCs). It is believed that direct allorecognition is the driving force behind early acute allograft rejection while indirect allorecognition is involved in chronic allograft rejection, a progressive condition characterized by graft vasculopathy and tissue fibrosis. Recently, we and others have reported that after transplantation of allogeneic skin and organs, donor MHC molecules are transferred from donor cells to the host's APCs via trogocytosis or extracellular vesicles. Recipient APCs having captured donor MHC molecules can either present them to T cells in their intact form on their surface (semi-direct pathway) or the form of peptides bound to self-MHC molecules (indirect pathway). The present article provides an overview of recent studies evaluating the role of intercellular exchange of MHC molecules in T cell alloimmunity and its contribution to allograft rejection and tolerance.

This study aimed to investigate the effect of interleukin-35 (IL-35) on inflamed lung tissue in a murine model of asthma. IL-35 was examined for its potential to induce regulatory lymphocytes during ovalbumin (OVA)-induced acute lung injury.

Female BALB/c mice sensitized with OVA and were treated with recombinant IL-35 (rIL-35) via intranasal or intraperitoneal routes and were administered 4 h before OVA challenge. The effects of rIL-35 treatment on the lung and blood levels of regulatory B cells (Bregs) and regulatory T cells (Tregs), as well as their production of immunosuppressive cytokines, were determined using flow cytometry and enzyme-linked immunosorbent assay (ELISA), respectively.

Treatment of OVA-sensitized asthmatic mice with rIL-35, whether administered intranasally or intraperitoneally, resulted in reduced lung inflammation and injury. This reduction was accompanied by an increase in the frequency of IL-35 producing Bregs, IL-35 and IL-10 producing Bregs, and conventional LAG3+ Tregs in the lung tissues and blood. This increase was more pronounced with intranasal rIL-35. Furthermore, there was a positive correlation between the levels of these regulatory cells and lung gene expression of IL-35 and IL-10, and an inverse correlation with both lung gene expression and plasma level of IL-17.

The results of this study suggest that IL-35, through its ability to increase Bregs and Tregs, is effective in reversing lung inflammation in the context of asthma. Since the increase was more pronounced with intranasal administration, this highlights the therapeutic potential of its local intrapulmonary application in managing asthma-related inflammation.

Interleukin-10 (IL-10) is a highly pleiotropic cytokine that regulates immunological homeostasis through anti-inflammatory and/or immunostimulatory functions. Moreover, IL-10 is well known to exert diverse roles in tumor immunology and immunotherapy. The present study investigated the presence of circulating tumor antigen-specific IL-10-producing T cells in patients with head and neck squamous cell carcinoma (HNSCC), and determined factors that may influence the immunodynamics of IL-10-producing T cells. In vitro, peripheral blood mononuclear cells (PBMCs) stimulated with the tumor antigens p53 and MAGE-A4 were evaluated for interferon (IFN)-γ/IL-10 production using the IFN-γ/IL-10 double-color enzyme-linked immunosorbent spot assay. The proportion of T cells expressing immune checkpoint molecules in PBMCs was analyzed using flow cytometry. Of the 18 patients with HNSCC, 2 (11.1%) and 9 (50.0%) exhibited p53-specific IFN-γ and IL-10 production, respectively. Meanwhile, MAGE-A4-specific IFN-γ and IL-10 production was detected in 4 (28.6%) and 7 (50.0%) of 14 patients. In the p53-specific responses, IL-10-producing T cells were observed in significantly more patients than IFN-γ producing T cells (P=0.0275). In both CD4+ and CD8+ T cells, the proportion of T cells expressing lymphocyte activation gene-3 (Lag-3) was significantly lower in patients with p53-specific IL-10 production than in those without. In certain patients, Lag-3 blockade enhanced tumor antigen-specific IL-10. Taken together, the present study successfully demonstrated that tumor antigen-specific IL-10-producing T cells exist in the peripheral blood of patients with HNSCC and that Lag-3+ T cells may serve an important role in modulating IL-10-producing T cells. These findings provide novel insights into the roles of IL-10 and Lag-3 in mediating antitumor immune responses.

Blockade of immune checkpoint receptors has shown outstanding efficacy for tumor immunotherapy. Promising treatment with anti-lymphocyte-activation gene-3 (LAG-3) has already been recognized as the next efficacious treatment, but there is still limited understanding of the mechanism of LAG-3-mediated immune suppression. Here, utilizing high-resolution molecular imaging, we find a mechanism of CD4 T cell suppression via LAG-3, in which LAG-3-bound major histocompatibility complex (MHC) class II molecules on antigen-presenting cells (APCs) gather at the central region of an immunological synapse and are trans-endocytosed by T cell receptor-driven internalization motility toward CD4 and CD8 T cells expressing LAG-3. Downregulation of MHC class II molecules on APCs thus results in the attenuation of their antigen-presentation function and impairment of CD4 T cell activation. From these data, anti-LAG-3 treatment is suggested to have potency to directly block the inhibitory signaling via LAG-3 and simultaneously reduce MHC class II expression on APCs by LAG-3-mediated trans-endocytosis for recovery from T cell exhaustion.

The collapse of immune homeostasis induces type 1 diabetes (T1D). In T1D, uncontrolled immune attacks against islet β cells reduce insulin secretion, resulting in hyperglycaemia and various complications. Type 1 regulatory (Tr1) cell therapy is a promising approach for the treatment of T1D. Tr1 cells are a subset of regulatory T (Treg) cells that are characterised by high interleukin-10 secretion and forkhead box protein P3 non-expression. Tr1 cells are reduced and have impaired function in patients with T1D. Immunotherapy is used to treat various diseases, and Treg cells have been applied to treat T1D in animal models and clinical trials. However, the safety and efficacy of Tr1 cells in treating diabetes and other diseases remain unclear. In this review, we aim to investigate the identification and biological function of Tr1 cells and related studies on immune diseases; additionally, we discuss the feasibility, limitations, and possible solutions of Tr1 cell therapy in T1D. This review shows that T1D is caused by an immune imbalance where defective Tr1 cells fail to control effector T cells, leading to the destruction of islet β cells. However, Tr1 cell therapy is safe and effective for other immune diseases, suggesting its potential for treating T1D.

Progesterone receptor (PR) serves as a crucial prognostic and predictive marker in breast cancer. Nonetheless, the interplay between PR and the tumor immune microenvironment remains inadequately understood. This investigation employs bioinformatics analyses, mouse models, and clinical specimens to elucidate the impact of PR on immune microenvironment and identify potential targets for immunotherapy, furnishing valuable guidance for clinical practice.

Analysis of immune infiltration score by Xcell between PR-positive and PR-negative breast cancer tumors. Construction of overexpression mouse progesterone receptor (mPgr) EMT-6 cell was to explore the tumor immune microenvironment. Furthermore, anti- Lymphocyte-activation gene 3 (LAG3) therapy aimed to investigate whether PR could influence the effectiveness of immune treatments.

Overexpression mPgr inhibited tumor growth in vitro, but promoted tumor growth in Balb/c mouse. Flow cytometry showed that the proportion and cytotoxicity of CD8+T cells in tumor of overexpressing mPgr group were significantly reduced. The significant reduction in overexpressing mPgr group was found in the proportions of LAG3+CD8+ T cells and LAG3+ Treg T cells. Anti-LAG3 treatment resulted in reduced tumor growth in EV group mouse rather than in overexpressing mPgr group. Patents derived tumor fragment (PDTF) also showed higher anti-tumor ability of CD3+T cell in patents' tumor with PR <20% after anti-human LAG3 treatment in vitro.

The mPgr promotes tumor growth by downregulating the infiltration and function of cytotoxic cell. LAG3 may be a target of ER-positive breast cancer immunotherapy. The high expression of PR hinders the sensitivity to anti-LAG3 treatment.

Immune checkpoint inhibitors (ICIs) have achieved remarkable success in clinical research and practice. Notably, liver metastasis is not sensitive to ICIs. Liver locoregional therapies can cause irreversible damage to tumor cells and release tumor antigens, thereby providing a rationale for immunotherapy treatments in liver metastasis. The combination therapy of ICIs with locoregional therapies is a promising option for patients with liver metastasis. Preclinical studies have demonstrated that combining ICIs with locoregional therapies produces a significantly synergistic anti-tumor effect. However, the current evidence for the efficacy of ICIs combined with locoregional therapies remains insufficient. Therefore, we review the literature on the mechanisms of locoregional therapies in treating liver metastasis and the clinical research progress of their combination with ICIs.

CD4+ T cells can either enhance or inhibit tumour immunity. Although regulatory T cells have long been known to impede antitumour responses1-5, other CD4+ T cells have recently been implicated in inhibiting this response6,7. Yet, the nature and function of the latter remain unclear. Here, using vaccines containing MHC class I (MHC-I) neoantigens (neoAgs) and different doses of tumour-derived MHC-II neoAgs, we discovered that whereas the inclusion of vaccines with low doses of MHC-II-restricted peptides (LDVax) promoted tumour rejection, vaccines containing high doses of the same MHC-II neoAgs (HDVax) inhibited rejection. Characterization of the inhibitory cells induced by HDVax identified them as type 1 regulatory T (Tr1) cells expressing IL-10, granzyme B, perforin, CCL5 and LILRB4. Tumour-specific Tr1 cells suppressed tumour rejection induced by anti-PD1, LDVax or adoptively transferred tumour-specific effector T cells. Mechanistically, HDVax-induced Tr1 cells selectively killed MHC-II tumour antigen-presenting type 1 conventional dendritic cells (cDC1s), leading to low numbers of cDC1s in tumours. We then documented modalities to overcome this inhibition, specifically via anti-LILRB4 blockade, using a CD8-directed IL-2 mutein, or targeted loss of cDC2/monocytes. Collectively, these data show that cytotoxic Tr1 cells, which maintain peripheral tolerance, also inhibit antitumour responses and thereby function to impede immune control of cancer.

In the last decade, cell therapies have revolutionized the treatment of some diseases, earning the definition of being the "third pillar" of therapeutics. In particular, the infusion of regulatory T cells (Tregs) is explored for the prevention and control of autoimmune reactions and acute/chronic allograft rejection. Such an approach represents a promising new treatment for autoimmune diseases to recover an immunotolerance against autoantigens, and to prevent an immune response to alloantigens. The efficacy of the in vitro expanded polyclonal and antigen-specific Treg infusion in the treatment of a large number of autoimmune diseases has been extensively demonstrated in mouse models. Similarly, experimental work documented the efficacy of Treg infusions to prevent acute and chronic allograft rejections. The Treg therapy has shown encouraging results in the control of type 1 diabetes (T1D) as well as Crohn's disease, systemic lupus erythematosus, autoimmune hepatitis and delaying graft rejection in clinical trials. However, the best method for Treg expansion and the advantages and pitfalls with the different types of Tregs are not fully understood in terms of how these therapeutic treatments can be applied in the clinical setting. This review provides an up-to-date overview of Treg infusion-based treatments in autoimmune diseases and allograft transplantation, the current technical challenges, and the highlights and disadvantages of this therapeutic approaches."

Cenicriviroc, a dual CCR2/CCR5 antagonist, initially developed as an anti-HIV drug, has shown promising results in nonalcoholic steatohepatitis phase 2 clinical trials. It inhibits the infiltration and activation of CCR2+/CCR5+ monocytes and macrophages to the site of liver injury, preventing liver fibrosis. However, the role of Cenicriviroc in the modulation of helper T cell differentiation and functions remains to be explored. In inflamed colons of Crohn's disease patients, CCR2+ and CCR5+ CD4+ T cells are enriched. Considering the role of CCR2+ and CCR5+ T cells in IBD pathogenesis, we investigated the potential role of Cenicriviroc in colitis. Our in vitro studies revealed that Cenicriviroc inhibits Th1-, Th2-, and Th17-cell differentiation while promoting the generation of type 1 regulatory T cells (Tr1), known for preventing inflammation through induction of IL-10. This study is the first to report that Cenicriviroc promotes Tr1 cell generation by up-regulating the signature of Tr1 cell transcription factors such as c-Maf, Prdm1, Irf-1, Batf, and EGR-2. Cenicriviroc displayed a protective effect in experimental colitis models by preventing body weight loss and intestinal inflammation and preserving epithelial barrier integrity. We show that Cenicriviroc induced IL-10 and inhibited the generation of pro-inflammatory cytokines IFN-γ, IL-17, IL-6, and IL-1β during colitis. Based on our data, we propose Cenicriviroc as a potential therapeutic in controlling tissue inflammation by inhibiting the generation and functions of effector T cells and promoting the induction of anti-inflammatory Tr1 cells.

Type 2 diabetes mellitus (T2DM) is usually accompanied by a low-grade inflammatory phenomenon, which participates in the pathogenesis of different complications of this condition. The inflammatory response is under the regulation of different mechanisms, including T regulatory (Treg) lymphocytes. However, the possible role of type 1 T regulatory (Tr1) cells in T2DM has not been explored so far.

To carry out a quantitative analysis of Tr1 lymphocytes and other immune cell subsets in patients with T2DM and correlate these results with clinical findings and treatments.

Sixty patients with T2DM and twenty-three healthy controls were included in the study. Biochemical and anthropometric variables were evaluated, and Tr1 lymphocytes (CD4+CD49+LAG-3+IL-10+) and other cell subsets (Th17, Th22 and Foxp3 + Treg cells) were analyzed in peripheral blood samples by multiparametric flow cytometry.

Significant increased levels of Tr1 cells were detected in patients with severe and mild disease, compared to healthy controls. In addition, CD4+IL-10+ lymphocytes were also increased in patients with T2DM. In contrast, similar levels of Foxp3+ Treg cells, Th17 and Th22 lymphocytes were observed in patients and controls. Likewise, no significant associations were detected between Tr1 cell levels and different clinical and laboratory parameters. However, those patients receiving glucagon-like peptide-1 receptor agonists (GLP-1-RA) showed similar levels of Tr1 cells than healthy controls, and significant lower numbers than untreated patients.

We observed an increase in Tr1 and CD4+IL10+ lymphocyte levels in T2DM. Moreover, GLP1-RA treatment was significantly associated with normalization of the Tr1 levels. This highlights another potential immune dysfunction in patients with T2DM, which could participate in the pathogenesis of this condition.

Regulatory T cells (Tregs) are essential to maintain immune homeostasis by promoting self-tolerance. Reduced Treg numbers or functionality can lead to a loss of tolerance, increasing the risk of developing autoimmune diseases. An overwhelming variety of human Tregs has been described, based on either specific phenotype, tissue compartment, or pathological condition, yet the bulk of the literature only addresses CD25-positive and CD127-negative cells, coined by naturally occurring Tregs (nTregs), most of which express the transcription factor Forkhead box protein 3 (FOXP3). While the discovery of FOXP3 was seminal to understanding the origin and biology of nTregs, there is evidence in humans that not all T cells expressing FOXP3 are regulatory, and that not all Tregs express FOXP3. Namely, the activation of human T cells induces the transient expression of FOXP3, irrespective of whether they are regulatory or inflammatory effectors, while some induced T cells that may be broadly defined as Tregs (e.g., Tr1 cells) typically lack demethylation and do not express FOXP3. Furthermore, it is unknown whether and how many nTregs exist without FOXP3 expression. Several other candidate regulatory molecules, such as GITR, Lag-3, GARP, GPA33, Helios, and Neuropilin, have been identified but subsequently discarded as Treg-specific markers. Multiparametric analyses have uncovered a plethora of Treg phenotypes, and neither single markers nor combinations thereof can define all and only Tregs. To date, only the functional capacity to inhibit immune responses defines a Treg and distinguishes Tregs from inflammatory T cells (Teffs) in humans. This review revisits current knowledge of the Treg universe with respect to their heterogeneity in phenotype and function. We propose that it is unavoidable to characterize human Tregs by their phenotype in combination with their function, since phenotype alone does not unambiguously define Tregs. There is an unmet need to align the expression of specific markers or combinations thereof with a particular suppressive function to coin functional Treg entities and categorize Treg diversity.

The glycoprotein CD226 plays a key role in regulating immune cell function. Soluble CD226 (sCD226) is increased in sera of patients with several chronic inflammatory diseases but its levels in neuroinflammatory diseases such as multiple sclerosis (MS) are unknown.

To investigate the presence and functional implications of sCD226 in persons with multiple sclerosis (pwMS) and other neurological diseases.

The mechanisms of sCD226 production were first investigated by analyzing CD226 surface expression levels and supernatants of CD3/CD226-coactivated T cells. The role of sCD226 on dendritic cell maturation was evaluated. The concentration of sCD226 in the sera from healthy donors (HD), pwMS, neuromyelitis optica (NMO), and Alzheimer's disease (AD) was measured.

CD3/CD226-costimulation induced CD226 shedding. Addition of sCD226 to dendritic cells during their maturation led to an increased production of the pro-inflammatory cytokine interleukin (IL)-23. We observed a significant increase in sCD226 in sera from pwMS and NMO compared to HD and AD. In MS, levels were increased in both relapsing-remitting multiple sclerosis (RRMS) and secondary-progressive multiple sclerosis (SPMS) compared to clinically isolated syndrome (CIS).

Our data suggest that T-cell activation leads to release of sCD226 that could promote inflammation and raises the possibility of using sCD226 as a biomarker for neuroinflammation.

The active vitamin A metabolite, all-trans-retinoic acid (RA), primes precursor dendritic cells (DCs) into a mucosal phenotype with tolerogenic properties characterized by the expression of integrin CD103. CD103+ DCs can counteract pathogenic Th1 and Th17 in inflammatory bowel disease (IBD) or celiac disease (CD). Tolerogenic manipulation of DCs using nanoparticles carrying tolerogenic adjuvants and disease-specific antigens is a valuable treatment strategy to induce antigen-specific mucosal tolerance in vivo. Here, we investigated the effects of RA-loaded liposomes on human DC phenotype and function, including DC-driven T-cell development, both during the generation of monocyte-derived DCs (moDCs) as well as by priming immature moDCs. RA liposomes drove CD103+ DC differentiation as well as ALDH1A2 expression in DCs. Neutrophil-dependent Th17 cell development was reduced by RA-liposome-differentiated and RA-liposome-primed DCs. Moreover, RA liposome treatment shifted T-cell development toward a Th2 cell profile. Importantly, RA liposomes induced the development of IL-10-producing and FoxP3+ regulatory T cells (Tregs) of various Treg subsets, including ICOS+ Tregs, that were potent inhibitors of bystander memory T-cell proliferation. Taken together, RA-loaded liposomes could be a novel treatment avenue for IBD or CD patients.

Dendritic cells (DCs) are professional antigen-presenting cells and trigger downstream immune responses to antigen while integrating cellular pathogen and damage-associated molecular pattern (PAMP and DAMP) or immunomodulatory signals. In healthy individuals, resting and tolerogenic DCs draining skin and intestine facilitate expansion of regulatory T cells (Treg) to maintain peripheral antigen-specific immune tolerance. In patients with rheumatic diseases, however, DCs activated by PAMPs and DAMPs expand self-reactive effector T cells, including follicular helper T cells that promote the expansion of activated autoreactive B cells, chronic inflammation and end-organ damage. With the development of cellular and nanoparticle (NP)-based self-antigen-specific immunotherapies we here consider the new opportunities and the challenges for restoring immunoregulation in the treatment and prevention of autoimmune inflammatory rheumatic conditions through DCs.

In many autoimmune diseases, autoantigen-specific Th17 cells play a pivotal role in disease pathogenesis. Th17 cells can transdifferentiate into other T cell subsets in inflammatory conditions, however, there have been no attempts to target Th17 cell plasticity using vaccines. We investigated if autoantigen-specific Th17 cells could be specifically targeted using a therapeutic vaccine approach, where antigen was formulated in all-trans retinoic acid (ATRA)-containing liposomes, permitting co-delivery of antigen and ATRA to the same target cell. Whilst ATRA was previously found to broadly reduce Th17 responses, we found that antigen formulated in ATRA-containing cationic liposomes only inhibited Th17 cells in an antigen-specific manner and not when combined with an irrelevant antigen. Furthermore, this approach shifted existing Th17 cells away from IL-17A expression and transcriptomic analysis of sorted Th17 lineage cells from IL-17 fate reporter mice revealed a shift of antigen-specific Th17 cells to exTh17 cells, expressing functional markers associated with T cell regulation and tolerance. In the experimental autoimmune encephalomyelitis (EAE) mouse model of MS, vaccination with myelin-specific (MOG) antigen in ATRA-containing liposomes reduced Th17 responses and alleviated disease. This highlights the potential of therapeutic vaccination for changing the phenotype of existing Th17 cells in the context of immune mediated diseases.

Maintenance of CD4 T cells during chronic infections is vital for limiting pathogen burden and disease recrudescence. Although inhibitory receptor expression by CD4 T cells is commonly associated with immune suppression and exhaustion, such cell-intrinsic mechanisms that control activation are also associated with cell survival. Using a mouse model of visceral leishmaniasis (VL), we discovered a subset of lymphocyte activation gene 3 (LAG-3)-expressing CD4 T cells that co-express CXCR5. Although LAG3+CXCR5+ CD4 T cells are present in naive mice, they expand during VL. These cells express gene signatures associated with self-renewal capacity, suggesting progenitor-like properties. When transferred into Rag1-/- mice, these LAG3+CXCR5+ CD4 T cells differentiated into multiple effector types upon Leishmania donovani infection. The transcriptional repressor B cell lymphoma-6 was partially required for their maintenance. Altogether, we propose that the LAG3+CXCR5+ CD4 T cell subset could play a role in maintaining CD4 T cell responses during persistent infections.

Human adaptive immunity is orchestrated by effector and regulatory T (Treg) cells. Natural Tregs arise in the thymus where they are shaped to recognize self-antigens, while type 1 Tregs or Tr1 cells are induced from conventional peripheral CD4 + T cells in response to peripheral antigens, such as alloantigens and allergens. Tr1 cells have been developed as a potential therapy for inducing antigen-specific tolerance, because they can be rapidly differentiated in vitro in response to a target antigen. However, the epigenetic landscape and the identity of transcription factors (TFs) that regulate differentiation, phenotype, and functions of human antigen-specific Tr1 cells is largely unknown, hindering Tr1 research and broader clinical development. Here, we reveal the unique epigenetic signature of antigen-specific Tr1 cells, and TFs that regulate their differentiation, phenotype and function. We showed that in vitro induced antigen-specific Tr1 cells are distinct both clonally and transcriptionally from natural Tregs and other conventional CD4 + T cells on a single-cell level. An integrative analysis of Tr1 cell epigenome and transcriptome identified a TF signature unique to antigen-specific Tr1 cells, and predicted that IRF4, BATF, and MAF act as their transcriptional regulators. Using functional genomics, we showed that each of these TFs play a non-redundant role in regulating Tr1 cell differentiation, suppressive function, and expression of co-inhibitory and cytotoxic proteins. By using the Tr1-specific TF signature as a molecular fingerprint, we tracked Tr1 cells in peripheral blood of recipients of allogeneic hematopoietic stem cell transplantation treated with adoptive Tr1 cell therapy. Furthermore, the same signature identified Tr1 cells in resident CD4 + T cells in solid tumors. Altogether, these results reveal the epigenetic signature and the key transcriptional regulators of human Tr1 cells. These data will guide mechanistic studies of human Tr1 cell biology and the development and optimization of adoptive Tr1 cell therapies.

Celiac Disease (CD) is a T-cell mediated disorder caused by immune response to gluten, although the mechanisms underlying CD progression are still elusive. We analyzed immune cell composition, plasma cytokines, and gliadin-specific T-cell responses in patients with positive serology and normal intestinal mucosa (potential-CD) or villous atrophy (acute-CD), and after gluten-free diet (GFD). We found: an inflammatory signature and the presence of circulating gliadin-specific IFN-γ+ T cells in CD patients regardless of mucosal damage; an increased frequency of IL-10-secreting dendritic cells (DC-10) in the gut and of circulating gliadin-specific IL-10-secreting T cells in potential-CD; IL-10 inhibition increased IFN-γ secretion by gliadin-specific intestinal T cells from acute- and potential-CD. On GFD, inflammatory cytokines normalized, while IL-10-producing T cells accumulated in the gut. We show that IL-10-producing cells are fundamental in controlling pathological T-cell responses to gluten: DC-10 protect the intestinal mucosa from damage and represent a marker of potential-CD.