The regulatory T cell family: distinct subsets and their interrelations

Regulatory T Cell Dysfunction in Autoimmune Diseases

Regulatory T cells (Tregs), a suppressive subpopulation of T cells, are potent mediators of peripheral tolerance, responsible for immune homeostasis. Many autoimmune diseases exhibit disruptions in Treg function or quantity, resulting in an imbalance between protective and pathogenic immune cells. Selective expansion or manipulation of Tregs is a promising therapeutic approach for autoimmune diseases. However, the extensive diversity of Treg subpopulations and the multiple approaches used for Treg identification leads to high complexity, making it difficult to develop a successful treatment capable of modulating Tregs. In this review, we describe the suppressive mechanisms, subpopulations, classification, and identification methodology for Tregs, and their role in the pathogenesis of autoimmune diseases.

Translating mechanisms into therapeutic strategies for immune thrombocytopenia (ITP): Lessons from clinical trials

Immune thrombocytopenia (ITP) is an autoimmune disorder that causes a significant reduction in peripheral blood platelet count. Fortunately, due to an increased understanding of ITP, there have been significant improvements in the diagnosis and treatment of these patients. Over the past decade, there have been a variety of proven therapeutic options available for ITP patients, including intravenous immunoglobulins (IVIG), Rituximab, corticosteroids, and thrombopoietin receptor agonists (TPO-RAs). Although the effectiveness of current therapies in treating more than two-thirds of patients, still some patients do not respond well to conventional therapies or fail to achieve long-term remission. Recently, a significant advancement has been made in identifying various mechanisms involved in the pathogenesis of ITP, leading to the development of novel treatments targeting these pathways. It seems that new agents that target plasma cells, Bruton tyrosine kinase, FcRn, platelet desialylation, splenic tyrosine kinase, and classical complement pathways are opening new ways to treat ITP. In this study, we reviewed the pathophysiology of ITP and summarized updates in this population's management and treatment options. We also took a closer look at the 315 ongoing trials to investigate their progress status and compare the effectiveness of interventions. May our comprehensive view of ongoing clinical trials serve as a guiding beacon, illuminating the path towards future trials of different drugs in the treatment of ITP patients.

Targeting T regulatory (Treg) cells in immunotherapy-resistant cancers

Primary or secondary (i.e., acquired) resistance is a common occurrence in cancer patients and is often associated with high numbers of T regulatory (Treg) cells (CD4+CD25+FOXP3+). The approval of ipilimumab and the development of similar pharmacological agents targeting cell surface proteins on Treg cells demonstrates that such intervention may overcome resistance in cancer patients. Hence, the clinical development and subsequent approval of Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) targeting agents can serve as a prototype for similar agents. Such new agents aspire to be highly specific and have a reduced toxicity profile while increasing effector T cell function or effector T/T regulatory (Teff/Treg) ratio. While clinical development with large molecules has shown the greatest advancement, small molecule inhibitors that target immunomodulation are increasingly entering early clinical investigation. These new small molecule inhibitors often target specific intracellular signaling pathways [e.g., phosphoinositide-3-kinase delta (PI3K-δ)] that play an important role in regulating the function of Treg cells. This review will summarize the lessons currently applied to develop novel clinical agents that target Treg cells.

Discrepancy in the suppressive function of regulatory T cells in allergic asthmatic vs. allergic rhinitis subjects upon low-dose allergen challenges

Background

Regulatory T cells (Tregs) contribute to the maintenance of immunological tolerance. There is evidence of impaired function of these cells in people with asthma and allergy. In this study, we evaluated and compared the function of Tregs in allergic asthmatic and allergic non-asthmatic patients, both before and after low-dose allergen challenges.

Methods

Three groups of subjects were recruited for a baseline evaluation: healthy controls without allergy or asthma, allergic asthmatic subjects, and allergic non-asthmatic subjects. All of them were subjected to expiratory flow measurements, sputum induction, and blood sampling. In addition, both groups of allergic subjects underwent low-dose allergen challenges. Tregs were isolated from whole blood using CD4+CD25high and CD127low staining. The suppression function was measured by flow cytometry. The levels of IL-10, IFN-γ, IgG4, IgA, and TGF-β were measured using ELISA, and sputum Foxp3 was evaluated using qRT-PCR.

Results

The suppressive function of Tregs in healthy controls was significantly higher than in allergic asthmatic or allergic non-asthmatic subjects. Repeated exposure to low doses of allergen increased the suppressor function of Tregs in allergic non-asthmatic subjects but decreased it in allergic asthmatic subjects. Foxp3 gene expression was increased in induced sputum in allergic non-asthmatic subjects, whereas it did not change in asthmatic subjects. Serum IL-10 level was decreased in allergic asthmatic subjects after allergen challenge but not in allergic non-asthmatic subjects. IFN-γ level increased upon allergen challenge in allergic non-asthmatic subjects. IgG4 level was higher in allergic non-asthmatic subjects than in allergic asthmatic subjects.

Conclusions

Low-dose allergen challenges stimulate the suppressor function of Tregs in non-asthmatic allergic subjects but not in allergic asthmatic subjects.

Polysaccharides from Paecilomyces hepiali Prevent Acute Colitis in Association with Modulating Gut Microbiota and Treg/Th17 Immune Balance in Mice

Cordyceps exopolysaccharide (CEP) has shown emerging potential in adjustment of gut microbiota and immune cell function. In this study, a water-soluble CEP with a molecular weight of 58.14 kDa was extracted from the fermentation broth of Paecilomyces hepiali, an endophytic fungus of Cordyceps sinensis. Our results indicated that Paecilomyces hepiali polysaccharide (PHP) showed significantly preventive potential on dextran sulfate sodium (DSS)-induced colitis in mice, which can prevent colon shortening, reduce intestinal epithelial cell (IEC) destruction, suppress inflammatory cell infiltration, and regulate the balance between regulatory T (Treg) cells and T helper type 17 (Th17) cells. Meanwhile, the disturbed gut microbiota was partially restored after PHP treatment. Further Pearson correlation coefficient analyses exhibited that the alteration of the gut microbiota was significantly related to adjustment of the IEC barrier and Treg/Th17 balance. In conclusion, all findings proposed that purified PHP has the potential to develop into a promising agent for colitis prevention and adjuvant therapy via maintaining intestinal homeostasis of gut microbiota and immune system.

Heat shock protein 60 in parasitic helminths: A role in immune responses and therapeutic applications

Heat shock protein 60 (HSP60) is an unique member of the heat shock protein family, being involved in parasite infections. To cope with harsh environments where parasites live, HSP60s are indispensable and involved in a variety of biological processes. HSP60s have relative low similarity among parasites, but their ATPase /Mg²⁺ active sites are highly conserved. The interactions of HSP60s with signaling pathway regulators in immune cells suggest a crucial role in immune responses, rendering them a potential therapeutic target. This paper reviews the current understandings of HSP60s in parasitic helminths in aspects of molecular characteristics, immunoregulatory responses and HSP60-based therapeutics.

Crosstalk between dendritic cells and regulatory T cells: Protective effect and therapeutic potential in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system related to autoimmunity and is characterized by demyelination, neuroinflammation, and neurodegeneration. Cell therapies mediated by dendritic cells (DCs) and regulatory T cells (Tregs) have gradually become accumulating focusing in MS, and the protective crosstalk mechanisms between DCs and Tregs provide the basis for the efficacy of treatment regimens. In MS and its animal model experimental autoimmune encephalomyelitis, DCs communicate with Tregs to form immune synapses and complete a variety of complex interactions to counteract the unbalanced immune tolerance. Through different co-stimulatory/inhibitory molecules, cytokines, and metabolic enzymes, DCs regulate the proliferation, differentiation and function of Tregs. On the other hand, Tregs inhibit the mature state and antigen presentation ability of DCs, ultimately improving immune tolerance. In this review, we summarized the pivotal immune targets in the interaction between DCs and Tregs, and elucidated the protective mechanisms of DC-Treg cell crosstalk in MS, finally interpreted the complex cell interplay in the manner of inhibitory feedback loops to explore novel therapeutic directions for MS.

Pharmacological effects of berberine on models of ulcerative colitis: A meta-analysis and systematic review of animal studies

Berberine (BBR) is the main active constituent of the Rhizoma coptidis (Huanglian) and has multiple biological activities. Although current evidence suggests that the BBR has a multi-target effect in ulcerative colitis (UC), its action and mechanism are unclear. The purpose of this meta-analysis was to assess the pharmacological effects and potential mechanisms of BBR in UC models. Studies were searched from four databases (PubMed, Embase, Web of Science, and Cochrane Library) until March 2022. Standardized mean difference (SMD) and 95% confidence intervals (CI) were used for the adjudication of outcomes. Stata 15.0 software was used for statistical analysis. Twenty-eight publications and 29 studies involving 508 animals were included in the meta-analysis. The results showed that BBR reduced disease activity index (DAI) scores, alleviated UC-induced colon length (CL) loss, prevented weight loss, and reduced histological colitis score (HCS). Mechanistically, BBR was found to reduce myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels, reduce levels of pro-inflammatory factors interleukin-1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), interferon-γ (IFN-γ) and mRNA expression of interleukin 17, increase levels of anti-inflammatory factor interleukin 10 (IL-10), and to increase levels of tight junction protein zonula occludens-1 (ZO-1) and occludin, which may involve antioxidant, anti-apoptotic, neuromodulation, anti-fibrotic, anti-inflammatory, barrier protection, and flora regulation aspects. However, additional attention should be paid to these outcomes due to the heterogeneity and methodological quality of the studies.

Changes in circulating TCF1- and GARP-associated regulatory T cell subsets reflect the clinical status of patients with chronic HBV infection

This study aimed to clarify the expression changes and clinical significance of regulatory T (Treg) cells and follicular regulatory T (TFR) cell subsets divided by glycoprotein A repetitions predominant protein (GARP) and T cell factor 1(TCF1) in peripheral blood of patients with chronic HBV infection. The peripheral blood of 26 chronic hepatitis B (CHB) patients, 27 inactive HBsAg carriers and 32 healthy controls were collected and GARP + percentages in Treg and TFR cells were analyzed by flow cytometry. In addition, Treg and TFR cell subsets sorted by CD62L and TCF1 were analyzed and compared. Correlation analyses were performed between Treg and TFR cell subpopulations and clinical parameters as well as cytokine concentrations, including IL-21, IL-10 and TGF-β1 in plasma. Circulating Treg and TFR levels were elevated in CHB patients. Moreover, GARP and TCF1 were up-regulated in circulating Treg and TFR cells of CHB patients. TCF1 + CD62L- Treg cells were increased while TCF1-CD62L + Treg cells were decreased in CHB patients. TCF1 + CD62L- and TCF1-CD62L- TFR cells were increased while TCF1 + CD62L + TFR cells were decreased in CHB patients. TCF1 + CD62L- Treg cells were positively correlated with HBV DNA, ALT and plasma IL-10, while TCF1 + CD62L + TFR cells were negatively correlated with HBV DNA, HBeAg, HBsAg, ALT, AST, T-BIL and positively correlated with plasma IL-21. Treg and TFR subsets sorted by TCF1, CD62L and GARP were changed in CHB patients. Changes in Treg and TFR functional subsets are associated with antiviral immunity in CHB patients.

New therapeutic strategies based on biasing IL-2 mutants for cancers and autoimmune diseases

Interleukin-2 (IL-2) is an immunomodulatory multifunctional cytokine. High-dose IL-2 was first approved by the U.S. Food and Drug Administration (FDA) in the 1990s for the treatment of metastatic renal cell carcinoma and metastatic melanoma. However, the short half-life of IL-2 and its toxicity caused by high-dose IL-2 limit the clinical use of IL-2. Recently, the development of cell-type-selective engineered IL-2 products become a hot research filed, mainly because IL-2 stimulates both regulatory T cells (Treg) and effector T cells (Teff) in vivo. The selective effect of IL-2 on Treg and Teff can be improved by designing biased IL-2 mutants, which showed reduced toxicity while being more effective in stimulating anti-tumor effector immunity or ameliorating autoimmune diseases. In this review we summarize the biological properties of IL-2 mutants reported so far. The design process and principle of IL-2 mutants, IL-2 mutant antibody complexes and IL-2 fusion proteins were discussed, which provided research basis for the design and application of IL-2 mutants in the future.

Advance of T regulatory cells in tumor microenvironment remodeling and immunotherapy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive, deadly, and is rarely diagnosed early. Regulatory T cells (Treg) are a multifunctional class of immunosuppressive T cells that help maintain immunologic homeostasis and participate in autoimmune diseases, transplants, and tumors. This cell type mediates immune homeostasis, tolerance, and surveillance and is associated with poor outcomes in PDAC. Tregs remodel the tumor immune microenvironment, mediate tumor immune escape, and promote tumor invasion and metastasis. A promising area of research involves regulating Tregs to reduce their infiltration into tumor tissues. However, the complexity of the immune microenvironment has limited the efficacy of immunotherapy in PDAC. Treg modulation combined with other treatments is emerging. This review summarizes the mechanisms of Tregs activity in tumor immune microenvironments in PDAC and the latest developments in immunotherapy and clinical trials.

T cells in the peritoneum

The peritoneal cavity is a fluid-packed area that houses most of the abdominal organs, including the omentum, a visceral adipose tissue with milky patches or groups of leukocytes organized in the same way to those observed in typical lymphoid tissues. A distinct population of leukocytes patrols the peritoneal cavity and travels in and out of the milky spots, facing antigens or pathogens in the peritoneal fluid and responding appropriately. T cells may play a crucial function in regulating adaptive immune responses to antigens in the peritoneal cavity to ensure tissue homeostasis and healing. When peritoneal homeostasis is interrupted by inflammation, infection, obesity, or tumor metastasis, the omentum's dedicated fibroblastic stromal cells and mesothelial cells control peritoneal leukocyte recruitment and activation in unique ways. T cells, which employ their T cell receptor to target specific antigens, are an important component of the acquired immune response since they are present in the peritoneal cavity. The peritoneum provides a different environment for T cells to respond to pathogens. This chapter outlines the anatomy relevant to T cell function and biology, such as antigen processing/presentation, T cell activation, and the many T cell subpopulations in the peritoneal cavity, as well as their role in cancer or other infection.

Fingolimod ameliorates acetic acid-induced ulcerative colitis: An insight into its modulatory impact on pro/anti-inflammatory cytokines and AKT/mTOR signalling

BACKGROUND

Because of the approved immunomodulatory activities of fingolimod, the current study aimed at studying the curative potential of fingolimod against experimentally induced ulcerative colitis (UC) via modulating pro/anti-inflammatory cytokines release and AKT/mTOR signalling.

METHODS

UC was induced in rats by intracolonic instillation of acetic acid. Fingo (0.5 mg/kg/day, p.o.) was given for 8 consecutive days that started 48 h after UC induction.

RESULTS

Fingolimod increased body weight growth rate and colon body/weight and colon weight/length indices compared to the UC group. Fingolimod significantly decreased clinical evaluation score and macroscopic score compared to the UC group. The curative potential of fingolimod was further confirmed by histopathological examination revealing marked attenuation of mucosal injury and inflammatory cells infiltration. Fingolimod significantly decreased colon malondialdehyde content and increased colon glutathione contents compared to the UC group. Fingolimod also significantly decreased the expressions of pro-inflammatory cytokines interleukin-9 and T-helper 17 along with increasing the expression of anti-inflammatory interleukin-10 and transforming growth factor-β compared to the UC group. In addition, fingolimod decreased the expressions of AKT and mTOR compared to the UC group.

CONCLUSION

Fingolimod attenuated acetic acid-induced UC through its immunomodulatory effect by shifting the balance to favour anti-inflammatory cytokine production rather than pro-inflammatory cytokines and modulating the AKT/mTOR signalling.

Two novel human anti-CD25 antibodies with antitumor activity inversely related to their affinity and in vitro activity

High tumor regulatory T (Treg) cell infiltration is associated with poor prognosis of many cancers. CD25 is highly expressed on tumor Treg cells and is a potential target for Treg deletion. Previously characterized anti-CD25 antibodies appear to have limited efficacy in tumor inhibition. Here we identified two human anti-CD25 antibodies, BA9 and BT942, which did not prevent the activation of IL-2R signaling pathway by IL-2. BT942 had weaker binding and cytotoxic activity to human CD25-expressing cell lines than BA9. But both demonstrated significant tumor growth inhibition in early and late-stage animal cancer models. BT942 resulted in a higher expansion of CD8⁺ T cells and CD4⁺ T cells in tumor microenvironment in mouse MC38 model compared to BA9. BT942 also demonstrated significant higher tumor growth inhibition and higher expansion of CD8⁺ T cells and CD4⁺ T cells in combination with an anti-PD1 antibody. Pharmacokinetic study of BT942 in cynomolgus monkeys demonstrated a half-life of 206.97 ± 19.03 h. Structural analysis by cryo-EM revealed that BT942 recognizes an epitope on opposite side of the CD25-IL-2 binding site, consistent with no IL-2 signaling blockade in vitro. BT942 appears to be an excellent candidate for cancer immunotherapy.

The Kynurenine Pathway-New Linkage between Innate and Adaptive Immunity in Autoimmune Endocrinopathies

The kynurenine pathway (KP) is highly regulated in the immune system, where it promotes immunosuppression in response to infection or inflammation. Indoleamine 2,3-dioxygenase 1 (IDO1), the main enzyme of KP, has a broad spectrum of activity on immune cells regulation, controlling the balance between stimulation and suppression of the immune system at sites of local inflammation, relevant to a wide range of autoimmune and inflammatory diseases. Various autoimmune diseases, among them endocrinopathies, have been identified to date, but despite significant progress in their diagnosis and treatment, they are still associated with significant complications, morbidity, and mortality. The precise cellular and molecular mechanisms leading to the onset and development of autoimmune disease remain poorly clarified so far. In breaking of tolerance, the cells of the innate immunity provide a decisive microenvironment that regulates immune cells' differentiation, leading to activation of adaptive immunity. The current review provided a comprehensive presentation of the known role of IDO1 and KP activation in the regulation of the innate and adaptive arms of the immune system. Significant attention has been paid to the immunoregulatory role of IDO1 in the most prevalent, organ-specific autoimmune endocrinopathies-type 1 diabetes mellitus (T1DM) and autoimmune thyroiditis.

Progression on the Roles and Mechanisms of Tumor-Infiltrating T Lymphocytes in Patients With Hepatocellular Carcinoma

Primary liver cancer (PLC) is one of the most common malignancies in China, where it ranks second in mortality and fifth in morbidity. Currently, liver transplantation, hepatic tumor resection, radiofrequency ablation, and molecular-targeted agents are the major treatments for hepatocellular carcinoma (HCC). Overall, HCC has a poor survival rate and a high recurrence rate. Tumor-infiltrating lymphocytes (TILs) have been discovered to play essential roles in the development, prognosis, and immunotherapy treatment of HCC. As the major component cells of TILs, T cells are also proved to show antitumor and protumor effects in HCC. Foxp3+, CD8+, CD3+, and CD4+ T lymphocytes are the broadly studied subgroups of TILs. This article reviews the roles and mechanisms of different tumor-infiltrating T lymphocyte subtypes in HCC.

Ingestion of Lactobacillus rhamnosus modulates chronic stress-induced feather pecking in chickens

Feather pecking (FP) is a stress-induced neuropsychological disorder of birds. Intestinal dysbiosis and inflammation are common traits of these disorders. FP is, therefore, proposed to be a behavioral consequence of dysregulated communication between the gut and the brain. Probiotic bacteria are known to favorably modulate the gut microbiome and hence the neurochemical and immune components of the gut-brain axis. Consequently, probiotic supplementation represents a promising new therapeutic to mitigate widespread FP in domestic chickens. We monitored FP, gut microbiota composition, immune markers, and amino acids related to the production of neurochemicals in chickens supplemented with Lactobacillus rhamnosus or a placebo. Data demonstrate that, when stressed, the incidence of FP increased significantly; however, L. rhamnosus prevented this increase. L. rhamnosus supplementation showed a strong immunological effect by increasing the regulatory T cell population of the spleen and the cecal tonsils, in addition to limiting cecal microbiota dysbiosis. Despite minimal changes in aromatic amino acid levels, data suggest that catecholaminergic circuits may be an interesting target for further studies. Overall, our findings provide the first data supporting the use of a single-strain probiotic to reduce stress-induced FP in chickens and promise to improve domestic birds' welfare.

Cytotoxic T Lymphocytes (CTLs) and Kidney Transplantation: An Overview

Involvement of T lymphocytes in kidney transplantation is a well-developed topic; however, most of the scientific interest focused on the different type of CD4+ lymphocyte subpopulations. Few authors, instead, investigated the role of CD8+ T cells in renal transplantation and how deleterious they can be to long-term allograft survival. Recently, there has been a renewed interest in the CD8+ T cells involvement in the transplantation field with the aim to investigate the immunological mechanisms underlying the infiltration of CD8+ T cells and their biological functions in human kidney allografts. The purpose of the present review is to highlight the role of allo-reactive cytotoxic T lymphocytes (CTLs) CD8⁺ subset in allograft kidney recipients and their related clinical complications.

Exploring the Pathogenic Role and Therapeutic Implications of Interleukin 2 in Autoimmune Hepatitis

Interleukin 2 is essential for the expansion of regulatory T cells, and low-dose recombinant interleukin 2 has improved the clinical manifestations of diverse autoimmune diseases in preliminary studies. The goals of this review are to describe the actions of interleukin 2 and its receptor, present preliminary experiences with low-dose interleukin 2 in the treatment of diverse autoimmune diseases, and evaluate its potential as a therapeutic intervention in autoimmune hepatitis. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Interleukin 2 is critical for the thymic selection, peripheral expansion, induction, and survival of regulatory T cells, and it is also a growth factor for activated T cells and natural killer cells. Interleukin 2 activates the signal transducer and activator of transcription 5 after binding with its trimeric receptor on regulatory T cells. Immune suppressor activity is increased; anti-inflammatory interleukin 10 is released; pro-inflammatory interferon-gamma is inhibited; and activation-induced apoptosis of CD8⁺ T cells is upregulated. Preliminary experiences with cyclic injections of low-dose recombinant interleukin 2 in diverse autoimmune diseases have demonstrated increased numbers of circulating regulatory T cells, preserved regulatory function, improved clinical manifestations, and excellent tolerance. Similar improvements have been recognized in one of two patients with refractory autoimmune hepatitis. In conclusion, interferon 2 has biological actions that favor the immune suppressor functions of regulatory T cells, and low-dose regimens in preliminary studies encourage its rigorous investigation in autoimmune hepatitis.

The Therapeutic Potential of Regulatory T Cells: Challenges and Opportunities

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

Analysis of Same Selected Immunomodulatory Properties of Chorionic Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) represent a population of adherent cells that can be isolated from multiple adult tissues. MSCs have immunomodulatory capacity and the ability to differentiate into many cell lines. Research study examines the immunomodulatory properties of MSCs isolated from chorion (CMSCs). Following the stimulation process, it was found that MSCs are capable of immunomodulatory action via the release of bioactive molecules as well as through direct contact with the immune cells. Immunomodulatory potential of the CMSCs was analyzed by modifying proliferative capacity of mitogen-activated lymphocytes. CMSCs and lymphocytes were tested in cell-to-cell contact. Lymphocytes were stained with carboxyfluorescein diacetate succinimidyl ester. Inhibition of the proliferation of activated lymphocytes was observed. Following the co-cultivation, the expression of markers involved in the immune response modulation was assessed. Afterwards, an increase in CMSCs expression of IL-10 was detected. Following the co-cultivation with activated lymphocyte, adhesion molecules CD54 and CD44 in the CMSCs increased. An increase of CD54 expression was observed. The properties of CMSCs, adherence and differentiation ability, were confirmed. The phenotype of CMSCs CD105+, CD90+, CD73+, CD44+, CD29+, CD45−, CD34−, CD54+ was characterized. It was demonstrated that chorion-derived MSCs have important immunomodulatory effects.

Anti-inflammatory and immune-modulatory impacts of berberine on activation of autoreactive T cells in autoimmune inflammation

Autoreactive inflammatory CD4+ T cells, such as T helper (Th)1 and Th17 subtypes, have been found to associate with the pathogenesis of autoimmune disorders. On the other hand, CD4+ Foxp3+ T regulatory (Treg) cells are crucial for the immune tolerance and have a critical role in the suppression of the excessive immune and inflammatory response promoted by these Th cells. In contrast, dendritic cells (DCs) and macrophages are immune cells that through their inflammatory functions promote autoreactive T-cell responses in autoimmune conditions. In recent years, there has been increasing attention to exploring effective immunomodulatory or anti-inflammatory agents from the herbal collection of traditional medicine. Berberine, an isoquinoline alkaloid, is one of the main active ingredients extracted from medicinal herbs and has been shown to exert various biological and pharmacological effects that are suggested to be mainly attributed to its anti-inflammatory and immunomodulatory properties. Several lines of experimental study have recently investigated the therapeutic potential of berberine for treating autoimmune conditions in animal models of human autoimmune diseases. Here, we aimed to seek mechanisms underlying immunomodulatory and anti-inflammatory effects of berberine on autoreactive inflammatory responses in autoimmune conditions. Reported data reveal that berberine can directly suppress functions and differentiation of pro-inflammatory Th1 and Th17 cells, and indirectly decrease Th cell-mediated inflammation through modulating or suppressing other cells assisting autoreactive inflammation, such as Tregs, DCs and macrophages.

Granuloma formation and tissue pathology in Schistosoma japonicum versus Schistosoma mansoni infections

Schistosomiasis is the most important helminth disease in the world from a public health perspective. S mansoni and S japonicum account for the majority of global intestinal schistosomiasis cases, and the pathogenesis is widely assumed to be fundamentally similar. However, the majority of research on schistosomiasis has been carried out on S mansoni and comparisons between the two species are rarely made. Here, we will discuss aspects of both older and recent literature where such comparisons have been made, with a particular focus on the pathological agent, the host granulomatous response to the egg. Major differences between the two species are apparent in features such as egg production patterns and cellular infiltration; however, it is also clear that even subtle differences in the cascade of various cytokines and chemokines contribute to the different levels of pathology observed between these two main species of intestinal schistosomiasis. A better understanding of such differences at species level will be vital when it comes to the development of new treatment strategies and vaccines.

An emerging role of regulatory T-cells in cardiovascular repair and regeneration

Accumulating evidence has demonstrated that immune cells play an important role in the regulation of tissue repair and regeneration. After injury, danger signals released by the damaged tissue trigger the initial pro-inflammatory phase essential for removing pathogens or cellular debris that is later replaced by the anti-inflammatory phase responsible for tissue healing. On the other hand, impaired immune regulation can lead to excessive scarring and fibrosis that could be detrimental for the restoration of organ function. Regulatory T-cells (Treg) have been revealed as the master regulator of the immune system that have both the immune and regenerative functions. In this review, we will summarize their immune role in the induction and maintenance of self-tolerance; as well as their regenerative role in directing tissue specific response for repair and regeneration. The latter is clearly demonstrated when Treg enhance the differentiation of stem or progenitor cells such as satellite cells to replace the damaged skeletal muscle, as well as the proliferation of parenchymal cells including neonatal cardiomyocytes for functional regeneration. Moreover, we will also discuss the reparative and regenerative role of Treg with a particular focus on blood vessels and cardiac tissues. Last but not least, we will describe the ongoing clinical trials with Treg in the treatment of autoimmune diseases that could give clinically relevant insights into the development of Treg therapy targeting tissue repair and regeneration.

Adoptive Treg cell-based immunotherapy: Frontier therapeutic aspects in rheumatoid arthritis

The major current focus on treating rheumatoid arthritis is to put an end to long-term treatments and instead, specifically block widespread immunosuppression by developing antigen-specific tolerance, while also permitting an intact immune response toward other antigens to occur. There have been promising preclinical findings regarding adoptive Treg cells immunotherapy with a critically responsible function in the prevention of autoimmunity, tissue repair and regeneration, which make them an attractive candidate to develop effective therapeutic approaches to achieve this interesting concept in many human immune-mediated diseases, such as rheumatoid arthritis. Ex vivo or invivo manipulation protocols are not only utilized to correct Treg cells defect, but also to benefit from their specific immunosuppressive properties by identifying specific antigens that are expressed in the inflamedjoint. The methods able to address these deficiencies can be considered as a target for immunity interventions to restore appropriate immune function.

The Immune Response to the fVIII Gene Therapy in Preclinical Models

Neutralizing antibodies to factor VIII (fVIII), referred to as "inhibitors," remain the most challenging complication post-fVIII replacement therapy. Preclinical development of novel fVIII products involves studies incorporating hemophilia A (HA) and wild-type animal models. Though immunogenicity is a critical aspect of preclinical pharmacology studies, gene therapy studies tend to focus on fVIII expression levels without major consideration for immunogenicity. Therefore, little clarity exists on whether preclinical testing can be predictive of clinical immunogenicity risk. Despite this, but perhaps due to the potential for transformative benefits, clinical gene therapy trials have progressed rapidly. In more than two decades, no inhibitors have been observed. However, all trials are conducted in previously treated patients without a history of inhibitors. The current review thus focuses on our understanding of preclinical immunogenicity for HA gene therapy candidates and the potential indication for inhibitor treatment, with a focus on product- and platform-specific determinants, including fVIII transgene sequence composition and tissue/vector biodistribution. Currently, the two leading clinical gene therapy vectors are adeno-associated viral (AAV) and lentiviral (LV) vectors. For HA applications, AAV vectors are liver-tropic and employ synthetic, high-expressing, liver-specific promoters. Factors including vector serotype and biodistribution, transcriptional regulatory elements, transgene sequence, dosing, liver immunoprivilege, and host immune status may contribute to tipping the scale between immunogenicity and tolerance. Many of these factors can also be important in delivery of LV-fVIII gene therapy, especially when delivered intravenously for liver-directed fVIII expression. However, ex vivo LV-fVIII targeting and transplantation of hematopoietic stem and progenitor cells (HSPC) has been demonstrated to achieve durable and curative fVIII production without inhibitor development in preclinical models. A critical variable appears to be pre-transplantation conditioning regimens that suppress and/or ablate T cells. Additionally, we and others have demonstrated the potential of LV-fVIII HSPC and liver-directed AAV-fVIII gene therapy to eradicate pre-existing inhibitors in murine and canine models of HA, respectively. Future preclinical studies will be essential to elucidate immune mechanism(s) at play in the context of gene therapy for HA, as well as strategies for preventing adverse immune responses and promoting immune tolerance even in the setting of pre-existing inhibitors.

Increased proportion of functional subpopulations in circulating regulatory T cells in patients with chronic hepatitis B

AIM

This study was designed to investigate the levels of circulating regulatory T cells (Tregs), and their functional subpopulations and related cytokines in chronic hepatitis B patients (CHB) and inactive hepatitis B surface antigen carriers.

METHODS

The peripheral blood of 24 hepatitis B virus inactive carriers, 26 CHB patients, and 34 healthy controls was collected and analyzed by flow cytometry for Tregs and CD4⁺ CXCR5⁺ FoxP3⁺ follicular regulatory T cells. Interleukin (IL)-10, transforming growth factor-β, and IL-21 levels in plasma were determined by enzyme-linked immunosorbent assay. Proportions of functional Treg subpopulations were analyzed by staining of Helios, CD45RA and FoxP3, TIGIT, and CD226, and the correlations between Treg subsets and clinical indicators were explored.

RESULTS

CD4⁺ FoxP3⁺ levels in the peripheral blood of CHB patients were significantly increased, and the inhibitory ability of Tregs in CHB patients for cytokine secretion was stronger, and CD4⁺ CXCR5⁺ FoxP3⁺ follicular Tregs were also significantly higher than inactive carriers and healthy controls. Transforming growth factor-β and IL-10 in the plasma of CHB patients were significantly higher than those of healthy controls, with IL-21 levels not significantly changed. Circulating CD4⁺ CXCR5-FoxP3⁺ Treg cells in CHB patients were positively correlated with hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B virus DNA. The proportions of Helios⁺ FoxP3⁺ , CD45RA^- FoxP3^hi , and CD226^- TIGIT⁺ functional subpopulations in CD4⁺ CXCR5^- FoxP3⁺ Tregs in CHB patients were significantly increased, and they were significantly correlated with clinical indicators.

CONCLUSIONS

Circulating Tregs in CHB patients not only have elevated levels, but their follicular Treg subpopulations are also increased, and Tregs tend to have stronger immunosuppressive functions.

T Lymphocytes: The “Cellular” Arm of Acquired Immunity in the Peritoneum

T cells are an important part of the acquired immune response and target specific antigen with their T cell receptor. The peritoneum is a special milieu within which T cells react. We describe briefly the anatomy important for T cell function. T cell biology including antigen presentation, T cell activation, and the different T cell subpopulations are reviewed. We also define innate and acquired immunity and describe the role of polymorphonuclear cells and peritoneal mesothelial cells in the regulation of leukocyte population recruitment during peritonitis. We focus particularly on peritoneal lymphocytes and compare them to the regular lymphocyte populations in the circulation. We illustrate the role of PMCs in antigen presentation and discuss the changes of CD4+ helper T cell subtypes (Th1 and Th2) during peritoneal dialysis. The role of CD8+ cytotoxic T lymphocytes and their possible destructive role for the peritoneal membrane modified by advanced glycation end products are discussed. Polymorphonuclear cells play an important role in the regulation of inflammation and immunity. We describe their possible role in supporting T cells and particularly for generating memory CD8+ T cells by secretion of interleukin-15, a potent T cell growth factor. Light is shed on γδ T cells, a special T cell population that is able to recognize antigens without the restriction of antigen presentation. We end our review with a description of regulatory T cells. This cell population is extremely important in preventing autoimmunity and in the regulation of acquired immunity.

T Lymphocyte-Mediated Liver Immunopathology of Schistosomiasis

The parasitic worms, Schistosoma mansoni and Schistosoma japonicum, reside in the mesenteric veins, where they release eggs that induce a dramatic granulomatous response in the liver and intestines. Subsequently, infection may further develop into significant fibrosis and portal hypertension. Over the past several years, uncovering the mechanism of immunopathology in schistosomiasis has become a major research objective. It is known that T lymphocytes, especially CD4⁺ T cells, are essential for immune responses against Schistosoma species. However, obtaining a clear understanding of how T lymphocytes regulate the pathological process is proving to be a daunting challenge. To date, CD4⁺ T cell subsets have been classified into several distinct T helper (Th) phenotypes including Th1, Th2, Th17, T follicular helper cells (Tfh), Th9, and regulatory T cells (Tregs). In the case of schistosomiasis, the granulomatous inflammation and the chronic liver pathology are critically regulated by the Th1/Th2 responses. Animal studies suggest that there is a moderate Th1 response to parasite antigens during the acute stage, but then, egg-derived antigens induce a sustained and dominant Th2 response that mediates granuloma formation and liver fibrosis. In addition, the newly discovered Th17 cells also play a critical role in the hepatic immunopathology of schistosomiasis. Within the liver, Tregs are recruited to hepatic granulomas and exert an immunosuppressive role to limit the granulomatous inflammation and fibrosis. Moreover, recent studies have shown that Tfh and Th9 cells might also promote liver granulomas and fibrogenesis in the murine schistosomiasis. Thus, during infection, T-cell subsets undergo complicated cross-talk with antigen presenting cells that then defines their various roles in the local microenvironment for regulating the pathological progression of schistosomiasis. This current review summarizes a vast body of literature to elucidate the contribution of T lymphocytes and their associated cytokines in the immunopathology of schistosomiasis.

Chimeric antigen receptor T cells in solid tumors: a war against the tumor microenvironment

Chimeric antigen receptor (CAR) T cell is a novel approach, which utilizes anti-tumor immunity for cancer treatment. As compared to the traditional cell-mediated immunity, CAR-T possesses the improved specificity of tumor antigens and independent cytotoxicity from major histocompatibility complex molecules through a monoclonal antibody in addition to the T-cell receptor. CAR-T cell has proven its effectiveness, primarily in hematological malignancies, specifically where the CD 19 CAR-T cells were used to treat B-cell acute lymphoblastic leukemia and B-cell lymphomas. Nevertheless, there is little progress in the treatment of solid tumors despite the fact that many CAR agents have been created to target tumor antigens such as CEA, EGFR/EGFRvIII, GD2, HER2, MSLN, MUC1, and other antigens. The main obstruction against the progress of research in solid tumors is the tumor microenvironment, in which several elements, such as poor locating ability, immunosuppressive cells, cytokines, chemokines, immunosuppressive checkpoints, inhibitory metabolic factors, tumor antigen loss, and antigen heterogeneity, could affect the potency of CAR-T cells. To overcome these hurdles, researchers have reconstructed the CAR-T cells in various ways. The purpose of this review is to summarize the current research in this field, analyze the mechanisms of the major barriers mentioned above, outline the main solutions, and discuss the outlook of this novel immunotherapeutic modality.

Phloretin ameliorates dextran sulfate sodium-induced ulcerative colitis in mice by regulating the gut microbiota

Phloretin, extracted from the pericarp and velamen of apples or pears, is a dihydrochalcone flavonoid with anti-bacterial and anti-inflammatory activities. It has been reported that phloretin has anti-inflammatory effects in ulcerative colitis (UC) mice. However, the role of the gut microbiota in the phloretin anti-UC process remains unclear. In this study, we observed that the anti-UC effect of phloretin was affected by co-housing, probably because of the transmissible nature of the gut micobiota. Through fecal micobiota transplantation (FMT), the effects of the gut microbiota on the anti-UC of phloretin were further confirmed. UC was induced in mice by administrating 3% dextran sulfate sodium (DSS) in drinking water for 7 days. Phloretin (60 mg/kg) was administered by gavage every day during the experiment. Fecal microbes (10⁹ CFU/mL) from phloretin-treated UC mice were administered by gavage to non-phloretin-treated UC mice for 7 days. The results showed that FMT, like phloretin, ameliorated UC by improving disease symptoms and colon inflammation, balancing inflammatory cytokines, maintaining intestinal barrier integrity, restoring systemic immune function, inhibiting NF-κB and NLRP3 inflammasome activation and ameliorating the oxidant stress. Both FMT and phloretin treatment increased the levels of Bacteroidetes, Alistipes and Lactobacillus and decreased those of Firmicutes, Oscillibacter and Ruminiclostridium_6. Correlation analysis between gut microbes and micro-environmental factors revealed that Alistipes abundance was negatively correlated with DAI, pathological score, and TNF-α, IL-6 and IL-1β levels, and Alistipes was more abundant in phloretin or FMT treated UC mice. Oscillibacter abundance was significantly positively correlated with IL-6 and IL-1β levels and pathological score, and Oscillibacter was increased in UC mice. Furthermore, network analysis of the dominant genera revealed that Alistipes abundance was negatively related to Oscillibacter abundance. In conclusion, this study suggests that the anti-UC effects of phloretin are achieved through regulation of the gut microbiota and phloretin has the potential to be developed as a promising agent for the treatment of UC.

Akt3-Mediated Protection Against Inflammatory Demyelinating Disease

Akt is a serine/threonine protein kinase that plays a major role in regulating multiple cellular processes. While the isoforms Akt1 and Akt2 are involved in apoptosis and insulin signaling, respectively, the role for Akt3 remains uncertain. Akt3 is predominantly expressed in the brain, and total deletion of Akt3 in mice results in a reduction in brain size and neurodegeneration following injury. Previously, we found that Akt3-/- mice have a significantly worse clinical course during myelin-oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), an animal model in which autoreactive immune cells enter the CNS, resulting in inflammation, demyelination, and axonal injury. Spinal cords of Akt3-/- mice are severely demyelinated and have increased inflammation compared to WT, suggesting a neuroprotective role for Akt3 during EAE. To specifically address the role of Akt3 in neuroinflammation and maintaining neuronal integrity, we used several mouse strains with different manipulations to Akt3. During EAE, Akt3 Nmf350 mice (with enhanced Akt3 kinase activity) had lower clinical scores, a lag in disease onset, a delay in the influx of inflammatory cells into the CNS, and less axonal damage compared to WT mice. A significant increased efficiency of differentiation toward FOXP3 expressing iTregs was also observed in Akt3 Nmf350 mice relative to WT. Mice with a conditional deletion of Akt3 in CD4+ T-cells had an earlier onset of EAE symptoms, increased inflammation in the spinal cord and brain, and had fewer FOXP3+ cells and FOXP3 mRNA expression. No difference in EAE outcome was observed when Akt3 expression was deleted in neurons (Syn1-CKO). These results indicate that Akt3 signaling in T-cells and not neurons is necessary for maintaining CNS integrity during an inflammatory demyelinating disease.

The Tolerogenic Function of Regulatory T Cells in Pregnancy and Cancer

Regulatory T cells, a subpopulation of suppressive T cells, are potent mediators of self-tolerance and essential for the suppression of triggered immune responses. The immune modulating capacity of these cells play a major role in both transplantation, autoimmune disease, allergy, cancer and pregnancy. During pregnancy, low numbers of regulatory T cells are associated with pregnancy failure and pregnancy complications such as pre-eclampsia. On the other hand, in cancer, low numbers of immunosuppressive T cells are correlated with better prognosis. Hence, maternal immune tolerance toward the fetus during pregnancy and the escape from host immunosurveillance by cancer seem to be based on similar immunological mechanisms being highly dependent on the balance between immune activation and suppression. As regulatory T cells hold a crucial role in several biological processes, they may also be promising subjects for therapeutic use. Especially in the field of cancer, cell therapy and checkpoint inhibitors have demonstrated that immune-based therapies have a very promising potential in treatment of human malignancies. However, these therapies are often accompanied by adverse autoimmune side effects. Therefore, expanding the knowledge to recognize the complexities of immune regulation pathways shared across different immunological scenarios is extremely important in order to improve and develop new strategies for immune-based therapy. The intent of this review is to highlight the functional characteristics of regulatory T cells in the context of mechanisms of immune regulation in pregnancy and cancer, and how manipulation of these mechanisms potentially may improve therapeutic options.

The absolute counts of peripheral T lymphocyte subsets in patient with ankylosing spondylitis and the effect of low-dose interleukin-2

The aim of this analysis is to investigate the level of T cell subsets in ankylosing spondylitis (AS) and the effect of low-dose interleukin 2 (IL-2).This is a retrospective cohort study, we collected basic information, inflammatory markers, BASDAI scores, and T lymphocyte subsets of peripheral blood in patients with AS, baseline analysis, correlation analysis and comparative analysis before and after treatment were performed.Data from 73 patients (of these, 36 patients were treated with IL-2) and 85 the health were included. The absolute numbers of peripheral CD4 Treg and CD8 Treg cells were lower, while the Th17 cell number and the ratio of Th17/CD4 Treg and CD4/CD8 Treg were higher. The CD4 Treg levels and the ratio of Th17/CD4 Tregs were correlated with BASDAI. The CD4 Treg, CD8 Treg, and Th17 cells were increased after treatment with IL-2 and the ratio of Th17/CD4 Treg was decreased.Increase in ratio of Th17/CD4 Treg involved in the occurrence of AS. At the same time, low-dose IL-2 could decrease the ratio of Th17/CD4 Treg in short time, low-dose IL-2 can be used to treat autoimmune diseases to avoid adverse reactions caused by immunosuppressants. Further clinical study is needed on the efficacy of IL-2.

Adoptive transfer of regulatory T cells stimulated by Allogeneic Hepatic Stellate Cells mitigates liver injury in mice with concanavalin A-induced autoimmune hepatitis

Regulatory T cell (Treg)-based therapy can effectively control autoimmune hepatitis (AIH). Hepatic stellate cells (HSC) can selectively stimulate allogeneic Treg proliferation following liver transplantation. This study tested the therapeutic effect and potential mechanisms underlying the action of HSC-stimulated Tregs on AIH in a mouse model of Concanavalin A (ConA)-induced AIH. HSC were isolated from BALB/c mice and characterized. Splenic CD4⁺CD25⁺ Tregs were isolated from C57BL/6 mice by immunomagnetic beads. The cells were co-cultured with primary (HSC-0), the second generation of HSC (HSC-2) for 72 h. The proliferation of Tregs was determined by flow cytometry. Similarly, the Tregs were co-cultured with HSC in transwell plates to determine the potential cell-cell contact dependent. The CD4⁺CD25^- effector T cells (CFSE-Teffs) were co-cultured with Teff or Tregs in the presence or absence of HSC to determine the suppressive capacity of Tregs. The effects of Tregs or HSC-stimulated Tregs on AIH severity and the frequency of splenic Tregs and Th17 cells were examined in mice. Co-culture with HSC-2 significantly promoted Treg proliferation in a dose- and cell-cell contact-dependent manner, and allogeneic HSC enhanced the suppressive activity of Tregs to inhibit the proliferation of Teff in vitro. Adoptive transfer of Tregs, particularly of HSC-stimulated Tregs, significantly reduced liver injury, inflammation and Ishak modified histology activity index in AIH mice, which were associated with improving the balance of Treg and Th17 cell responses. Our data indicated that mature HSC stimulated allogeneic Treg proliferation in a dose and cell-cell contact-dependent manner, and HSC enhanced the suppressive activity of Tregs to inhibit the proliferation of Teff. Adoptive transfer of HSC-stimulated Tregs significantly reduced liver injury in AIH mice by modulating the balance of Treg and Th17 cell responses.

T cell subsets: an integral component in pathogenesis of rheumatic heart disease

Acute rheumatic fever (ARF) is a consequence of pharyngeal infection of group A streptococcal (GAS) infection. Carditis is the most common manifestation of ARF which occurs in 30-45% of the susceptible individuals. Overlooked ARF cases might further progress towards rheumatic heart disease (RHD) in susceptible individuals, which ultimately leads to permanent heart valve damage. Molecular mimicry between streptococcal antigens and human proteins is the most widely accepted theory to describe the pathogenesis of RHD. In the recent past, various subsets of T cells have been reported to play an imperative role in the pathogenesis of RHD. Alterations in various T cell subsets, viz. Th1, Th2, Th17, and Treg cells, and their signature cytokines influence the immune responses and are associated with pathogenesis of RHD. Association of other T cell subsets (Th3, Th9, Th22, and T_FH) is not defined in context of RHD. Several investigations have confirmed the up-regulation of adhesion molecules and thus infiltration of T cells into the heart tissues. T cells secrete both Th type 1 and type 2 cytokines and these auto-reactive T cells play a key role in progression of heart valve damage. In this review, we are going to discuss about the role of T cell subsets and their corresponding cytokines in the pathogenesis of RHD.

Intestinal CD4 Depletion in HIV / SIV Infection

Among the most significant findings in the pathogenesis of HIV infection was the discovery that almost total depletion of intestinal CD4+ T cells occurs rapidly after SIV or HIV infection, regardless of the route of exposure, and long before CD4+ T cell losses occur in blood or lymph nodes. Since these seminal discoveries, we have learned much about mucosal and systemic CD4+ T cells, and found several key differences between the circulating and intestinal CD4+ T cell subsets, both in phenotype, relative proportions, and functional capabilities. Further, specific subsets of CD4+ T cells are selectively targeted and eliminated first, especially cells critically important for initiating primary immune responses, and for maintenance of mucosal integrity (Th1, Th17, and Th22 cells). This simultaneously results in loss of innate immune responses, and loss of mucosal integrity, resulting in mucosal, and systemic immune activation that drives proliferation and activation of new target cells throughout the course of infection. The propensity for the SIV/HIV to infect and efficiently replicate in specific cells also permits viral persistence, as the mucosal and systemic activation that ensues continues to damage mucosal barriers, resulting in continued influx of target cells to maintain viral replication. Finally, infection and elimination of recently activated and proliferating CD4+ T cells, and infection and dysregulation of Tfh and other key CD4+ T cell results in hyperactive, yet non-protective immune responses that support active viral replication and evolution, and thus persistence in host tissue reservoirs, all of which continue to challenge our efforts to design effective vaccine or cure strategies.

Polymeric micro- and nanoparticles for immune modulation

New advances in biomaterial-based approaches to modulate the immune system are being applied to treat cancer, infectious diseases, and autoimmunity. Particulate systems are especially well-suited to deliver immunomodulatory factors to immune cells since their small size allows them to engage cell surface receptors or deliver cargo intracellularly after internalization. Biodegradable polymeric particles are a particularly versatile platform for the delivery of signals to the immune system because they can be easily surface-modified to target specific receptors and engineered to release encapsulated cargo in a precise, sustained manner. Micro- and nanoscale systems have been used to deliver a variety of therapeutic agents including monoclonal antibodies, peptides, and small molecule drugs that function to activate the immune system against cancer or infectious disease, or suppress the immune system to combat autoimmune diseases and transplant rejection. This review provides an overview of recent advances in the development of polymeric micro- and nanoparticulate systems for the presentation and delivery of immunomodulatory agents targeted to a variety of immune cell types including APCs, T cells, B cells, and NK cells.

Serum levels of proinflammatory, anti-inflammatory cytokines, and RANKL/OPG in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome

OBJECTIVE

To measure the expression of proinflammatory, anti-inflammatory cytokines, and receptor activator NK-κB ligand (RANKL)/osteoprotegerin (OPG) in synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO) syndrome, and to assess the relationship between those factors and disease activity.

METHODS

We studied 30 cases of SAPHO syndrome and 15 healthy controls. According to the Visual Analogue Scale (VAS) pain scores and Bath Ankylosing Spondylitis Activity Index (BASDAI), patients were divided into active group and stable group. The serum levels of IFN-γ, TNF-α, TGF-β1, IL-1β, IL-4, IL-6, IL-8, IL-17A, IL-22, RANKL, and OPG were determined by ELISA.

RESULTS

The active group IL-6 (2.34 ± 1.31 pg/ml), IL-8 (36.41 ± 12.93 pg/ml), and IL-17A (29.17 ± 4.01 pg/ml) levels were significantly higher than those in the stable group (p < .01) and healthy controls (p < .01). RANKL in active group (73.43 ± 57.07 pg/ml) was significantly higher than the ones in other groups (p < .0001), with increased RANKL/OPG ratio in the active group compared with other groups (p < .05). While the level of TGF-β1 in the active group was significantly lower than that in the stable and control groups (p < .0001). There was no significant difference with clinical significance were found in IFN-γ, TNF-α, IL-1β, IL-4, IL-22, and OPG.

CONCLUSION

In active SAPHO patients, there was an anomaly of proinflammatory and anti-inflammatory cytokines balance in SAPHO syndrome.

Potential Effect of Cyclophosphamide on Bleb Survival in Five Patients with Multiple Sclerosis Who Underwent Glaucoma Surgery

INTRODUCTION

The purpose of this case series was to report the potential role of cyclophosphamide (CY) on bleb survival and to evaluate the safety of the trabeculectomy procedure under immunosuppressant systemic therapy.

CASE SERIES

Five eyes of five patients with unresponsive to intraocular pressure (IOP) lowering medication, progressive glaucoma, underwent mytomicin C (MMC) augmented phaco-trabeculectomy, performed by the same surgeon, A.G., during the period from May 2015 to January 2016. All patients were treated with low doses of systemic CY at the time of surgery, to control their relapsing progressive multiple sclerosis (MS) form.

RESULTS

During a mean follow-up period of 20.6 ± 8.1 months, for cases of "complete success" (when the IOP was < 15 mmHg without glaucoma therapy) were observed, while one case was classified as a "qualified success" since the IOP was ≤ 15 mmHg with β-blocker drops. There were no bleb infections, nor bleb-related complications.

CONCLUSION

This study reports the safety of performing the filtration surgical procedure under immunosuppressant systemic therapy and provides a possible explication of CY anti-fibrotic mechanism and its possible role on bleb survival. Our findings may suggest new perspectives of study in this field.

Berberine Regulates Treg/Th17 Balance to Treat Ulcerative Colitis Through Modulating the Gut Microbiota in the Colon

Berberine (BBR), an alkaloid isolated from Rhizoma Coptidis, Cortex Phellode, and Berberis, has been widely used in the treatment of ulcerative colitis (UC). However, the mechanism of BBR on UC is unknown. In this study, we investigated the activities of T regulatory cell (Treg) and T helper 17 cell (Th17) in a dextran sulfate sodium (DSS)-induced UC mouse model after BBR administration. We also investigated the changes of gut microbiota composition using 16S rRNA analysis. We also examined whether BBR could regulate the Treg/Th17 balance by modifying gut microbiota. The mechanism was further confirmed by depleting gut microbiota through a combination of antibiotic treatment and fecal transplantations. Results showed that BBR treatment could improve the Treg/Th17 balance in the DSS-induced UC model. BBR also reduced diversity of the gut microbiota and interfered with the relative abundance of Desulfovibrio, Eubacterium, and Bacteroides. Moreover, BBR treatment did not influence the Treg/Th17 balance after the depletion of gut microbiota. Our results also revealed that fecal transplantation from BBR-treated mice could relieve UC and regulate the Treg/Th17 balance. In conclusion, our study provides evidence that BBR prevents UC by modifying gut microbiota and regulating the balance of Treg/Th17.

Emergence of NK Cell Hyporesponsiveness after Two IL-15 Stimulation Cycles

IL-15 is a cytokine playing a crucial role in the function of immune cells, including NK and CD8 T cells. In this study, we demonstrated that in vivo, in mice, IL-15-prestimulated NK cells were no longer able to respond to a second cycle of IL-15 stimulation. This was illustrated by defects in cell maturation, proliferation, and activation, seemingly linked to the environment surrounding NK cells but not related to the presence of CD4 regulatory T cells, TGF-β, or IL-10. Moreover, NK cells from immunodeficient mice could respond to two cycles of IL-15 stimulation, whereas an adoptive transfer of CD44⁺CD8⁺ cells impaired their responsiveness to the second cycle. Conversely, in immunocompetent mice, NK cell responsiveness to a second IL-15 stimulation was restored by the depletion of CD8⁺ cells. These biological findings refine our understanding of the complex mode of action of NK cells in vivo, and they should be taken into consideration for IL-15-based therapy.

Targeting regulatory T cells for improving cancer therapy: Challenges and prospects

OBJECTIVE

Regulatory T cells (Tregs) play a central role in immune responses to infectious agents and tumors. Paradoxically, Tregs protect self-cells from the immune response as a part of peripheral tolerance and prevents autoimmune disorders, whereas during the process of carcinogenesis, they are exploited by tumor cells for protection against antitumor immune responses. Therefore, Tregs are often considered as a major obstacle in anticancer therapy. The objective of this review is to provide a current understanding on Tregs as a potential cellular target for achieving therapeutic gain and discuss various approaches that are implicated at preclinical and clinical scenario.

RECENT FINDINGS

Several approaches like immunotherapy and adjuvant chemotherapy, which reduce Tregs population, have been found to be useful in improving local tumor control. Our recent observations with the glycolytic inhibitor, 2-deoxy-D-glucose, established as an adjuvant in radiotherapy and chemotherapy of tumors also show that potential of 2-deoxy-D-glucose to improve local tumor control is linked with its ability to reduce the Tregs pool.

CONCLUSIONS

Several published studies and emerging evidences indicate that suppression of Treg numbers, infiltration into the tumors, and function can improve the cancer therapy by enhancing the antitumor immunity.

Regulatory T cells: from the bench to the clinic and back

PURPOSE OF REVIEW

The main objective of this review is to briefly highlight how we gradually came to understand regulatory T cells (Tregs) and forkhead box p3 (FoxP3) biology, including their function and regulation. We will also discuss how this knowledge is being translated into the clinical setting and the significant challenges that need to be overcome.

RECENT FINDINGS

CD4FoxP3 Tregs are key players in immune regulation. Their deficiency and dysfunction have been implicated in the pathogenesis of many autoimmune diseases. This has led towards extensive work across the years to figure out the biology and suppressive mechanisms of these cells. Furthermore, Tregs' ability to suppress immune responses makes the idea of their utilization in adoptive immunotherapy appealing. Work has been underway to establish ideal methods to integrate Tregs into the management of autoimmune diseases and alloimmunity, either by treatment with IL-2 or infusion of ex-vivo expanded Tregs. Despite Tregs' scarcity and increased tendency for Activation-induced cell death, many groups have developed effective methods to expand them ex vivo.

SUMMARY

Although clinical trials are ongoing to test the safety and efficacy of regulatory cells in transplant recipients, it is vital to continue exploring the cellular and molecular mechanisms that control their stability and homeostasis.

The Dual Role of Treg in Cancer

Regulatory T cells (Tregs) represent a small subpopulation of CD4⁺ cells. Tregs are characterized by the expression of transcription factor Forkhead box protein 3 (FoxP3), also known as scurfin. Tregs are modulators of adaptive immune responses and play an important role in maintaining tolerance to self-antigens, providing the suppression associated with tumour microenvironment as well. These immunomodulatory properties are the main reason for the development of numerous therapeutic strategies, designed to inhibit the activity of cancer cells. However, due to Treg subpopulation diversity and its many functional pathways, the role of these cells in the cancer development and progression is still not fully understood.

Inhibition of CD8+ T cells and elimination of myeloid cells by CD4+ Foxp3- T regulatory type 1 cells in acute respiratory distress syndrome

Acute lung injury and acute respiratory distress syndrome (ARDS) are caused by rapid-onset bilateral pulmonary inflammation. We therefore investigated the potential role of interleukin (IL)-10⁺ CD4⁺ Tr1 cells, a regulatory T cell subset with previously identified immunosuppressive functions, in ARDS patients. We first showed that circulating Tr1 cells were upregulated in active and resolved ARDS patients compared to healthy controls and pneumonia patient controls. A significant fraction of these Tr1 cells expressed granzyme B and perforin, while most Tr1 cells did not express interferon gamma (IFN-γ), IL-4, IL-17 or FOXP3, suggesting that the effector functions of these Tr1 cells were primarily mediated by IL-10, granzyme B, and perforin. Indeed, Tr1 cells effectively suppressed CD8⁺ T cell IFN-γ production and induced lysis of monocytes and dendritic cells in vitro. The elimination of myeloid antigen-presenting cells depended on granzyme B production. We also discovered that Tr1 cells could be identified in the bronchoalveolar lavage fluid collected from ARDS patients. All these results suggested that Tr1 cells possessed the capacity to downregulate inflammation in ARDS. In support of this, we found that ARDS patients who resolved the inflammation and survived the syndrome contained significantly higher levels of Tr1 cells than ARDS patients who succumbed to the syndrome. Overall, this report added a novel piece of evidence that ARDS could be intervened by regulatory T cell-mediated suppressive mechanisms.

Regulatory T Cells in SLE: Biology and Use in Treatment

T regulatory cells (Tregs) represent a phenotypically and functionally heterogeneous group of lymphocytes that exert immunosuppressive activities on effector immune responses. Tregs play a key role in maintaining immune tolerance and homeostasis through diverse mechanisms which involve interactions with components of both the innate and adaptive immune systems. As in many autoimmune diseases, Tregs have been proposed to play a relevant role in the pathogenesis of systemic lupus erythematosus (SLE), an autoimmune disease characterized by a progressive breakdown of tolerance to self-antigens and the presence of concomitant hyperactive immune responses. Here, we review how Tregs dysfunction in SLE has been manipulated experimentally and preclinically in the attempt to restore, at last in part, the immune disturbances in the disease.