IL-35 production by inducible costimulator (ICOS)-positive regulatory T cells reverses established IL-17-dependent allergic airways disease

Adaptive plasticity of natural interleukin-35-induced regulatory T cells (Tr35) that are required for T-cell immune regulation

Background: IL-35 potently inhibits immune responses both in vivo and in vitro. However, the specific characteristics of IL-35-producing cells, including their developmental origin, cellular phenotype, and function, are unknown. Methods: By using a novel IL-35 reporter mouse (Ebi3-Dre-Thy1.1) and double transgenic fate-mapping reporter mice (35EbiT-Rosa26-rox-tdTomato reporter mice or Foxp3 fate-mapping system), we tracked and analyzed the differentiation and developmental trajectories of Tr35 cells in vivo. And then we investigated the therapeutic effects of OVA-specific Tr35 cells in an OVA-induced allergic airway disease model. Results: We identified a subset of cells, denoted Tr35 cells, that secrete IL-35 but do not express Foxp3. These cells have high expression of molecules associated with T-cell activation and can inhibit T-cell proliferation in vitro. Our analyses showed that Tr35 cells are a distinct subpopulation of cells that are independent of Tr1 cells. Tr35 cells exhibit a unique gene expression profile and tissue distribution. The presence of Thy1.1 (Ebi3) expression in Tr35 cells indicates their active secretion of IL-35. However, the proportion of ex-Tr35 cells (Thy1.1-) is significantly higher compared to Tr35 cells (Thy1.1+). This suggests that Tr35 cells possess the ability to regulate IL-35 expression rapidly in vivo. Tr35 cells downregulated the expression of the inflammatory cytokines IL-4, IFN-γ and IL-17A. However, once Tr35 cells lost IL-35 expression and became exTr35 cells, the expression of inflammatory cytokines was upregulated. Importantly, our findings indicate that Tr35 cells have therapeutic potential. In an OVA-induced allergic airway disease mouse model, Tr35 cell reinfusion significantly reduced airway hyperresponsiveness and histopathological airway and lung inflammation. Conclusions: We have identified a subset of Tregs, Tr35 cells, that are distinct from Tr1 cells. Tr35 cells can dynamically regulate the secretion of inflammatory cytokines by controlling IL-35 expression to regulate inflammatory immune responses.

Interplay of IL-33 and IL-35 Modulates Th2/Th17 Responses in Cigarette Smoke Exposure HDM-Induced Asthma

Cigarette smoke (CS) facilitates adverse effects on the airway inflammation and treatment of asthma. Here, we investigated the mechanisms by which CS exacerbates asthma. The roles of IL-33 and IL-35 in asthma development were examined by treatment with IL-33 knockout (IL-33 KO) or transfection of adenovirus encoding IL-35 (Ad-IL-35) in a murine model of cigarette smoke-exposure asthma. Furthermore, the involvement of IL-33 and IL-35 in regulating DCs and Th2/Th17 cells was examined in a coculture system of DCs with CD4+ T cells. Additionally, we observed the effect of CpG-ODNs on the balance of IL-33 and IL-35. We show that CS and house dust mite (HDM) exposure induced IL-33 and suppressed IL-35 levels in cigarette smoke-exposure asthma in vivo and in vitro. Treatment with IL-33 KO or Ad-IL-35 significantly attenuated airway hyperreactivity, goblet hyperplasia, airway remodelling, and eosinophil and neutrophil infiltration in the lung tissues from asthmatic mice. Furthermore, we demonstrated reciprocal regulation between CS and HDM-modulated IL-33 and IL-35. Mechanistically, IL-33 KO (or anti-ST2) and Ad-IL-35 attenuated Th2- and Th17-associated inflammation by downregulating TSLP-DC signalling. Finally, administration of CpG-ODNs suppressed the expression of IL-33/ST2 and elevated the levels of IL-35, which is mainly derived from CD4+Foxp+ Tregs, to alleviate Th2- and Th17-associated inflammation by inhibiting the activation of BMDCs. Taken together, the IL-33/ST2 pathway drives the DC-Th2 and Th17 responses of cigarette smoke-exposure asthma, while IL-35 has the opposite effect. CpG-ODNs represent a potential therapeutic strategy for modulating the balance of IL-33 and IL-35 to suppress allergic airway inflammation.

Estimating the salivary levels of IL-35 in smokers with periodontitis: A cross sectional study

Background

A refined network and integrated host immune response to bacteria are formed by anti-inflammatory cytokines and the cells that they are associated to IL-35 has been recognized as having strong suppressive activity in chronic inflammatory diseases, together with IL-10 and TGF-β. It is believed that inflammatory diseases like periodontitis trigger the inducible Treg population to express IL-35, expanding regulatory responses by increasing infection.

Aim

The objective is to estimate and compare the salivary IL-35 levels in Periodontally healthy subjects, smokers and non-smokers with Periodontitis in order to educate on the consequences of periodontal health among the diseased patients.

Materials and Methods

Totally 42 subjects were included and they were categorized into Group 1 (n = 14) as Periodontally healthy subjects, Group 2 (n = 14) as systemically healthy non-Smokers with periodontitis and Group 3 (n = 14) as systemically healthy smokers with periodontitis. Each subject was assessed for clinical parameters such as Plaque index, Gingival index, Probing depth, clinical attachment. A polypropylene tube was used to collect unstimulated saliva and centrifuged it at 800 × g for 10 min. Supernatants were collected and stored at -80◦C. A commercially available enzyme-linked immunosorbent assay kit was used to analyse levels of human salivary IL-35.

Results

The average age of the subjects in Group 1, Group 2 and Group 3 were 50.53, 52.93 and 52.07 years respectively. All three groups showed a statistically significant difference in clinical parameters including Plaque index, Gingival index, Probing depth and clinical attachment. The salivary IL-35 level was found to be elevated in non-smokers who have periodontitis compared to smokers with periodontitis and healthy individuals. Despite this, the salivary IL-35 levels were found to be statistically significant among three groups at P < 0.001.

Conclusion

The salivary levels of IL-35 were found to increase in Periodontitis patients with/without smoking, along with increased clinical parameters. IL-35 is considered a influential biomarker for periodontal disease.

Effects of mesenchymal stem cells on Treg cells in rats with colitis

The aim was to investigate the therapeutic effect of bone marrow mesenchymal stem cells (BM-MSC) on dextran sulfate sodium (DSS) induced colitis in rats and its effect on regulatory T cells (Treg). A model of DSS-induced colitis was established. BM-MSC was isolated and cultured to observe the efficacy of BM-MSC on colitis, including general vital signs, weight changes, colonic length changes, colonic histopathological changes, and colonic tissue MPO activity. The expression of inflammatory factors (IFN-γ, IL-4, IL-17, TGF-β) in colonic tissues was measured by real-time PCR. The amount of CD4 + CD25 + Treg was detected by flow cytometry. Real-time PCR was used to detect Foxp3+mRNA in CD4 + CD25 + Treg, western to detect Foxp3+protein expression in CD4 + CD25 + Treg, and ELISA was used to detect IL-35 and IL-10 cytokines in CD4 + CD25 + Treg culture supernatant. Results show that intravenous injection of BM-MSC significantly improved the clinical manifestations and histopathological changes in rats with experimental DSS colitis; significantly down-regulated the expression of inflammatory factors IFN-γ, IL-4, and IL-17 and up-regulated the expression of TGF-β in colon tissues; BM-MSC also increased the number of CD4+CD25+Foxp3+Treg and enhanced the function of CD4+CD25+Foxp3+Treg in colon tissues, and up-regulated the expression of IL-35. In conclusion, BM-MSC has a certain therapeutic effect on DSS-induced colitis. It can improve the general signs of colitis rats and reduce intestinal injury and inflammatory response. The immunoregulatory effect of BM-MSC is achieved by enhancing the function of CD4+CD25+Foxp3+Treg and up-regulating the secretion of immunosuppressive inflammatory factors.

Human IL-35 Inhibits the Bioactivity of IL-12 and Its Interaction with IL-12Rβ2

IL-35 is an immunosuppressive cytokine with roles in cancer, autoimmunity, and infectious disease. In the conventional model of IL-35 biology, the p35 and Ebi3 domains of this cytokine interact with IL-12Rβ2 and gp130, respectively, on the cell surface of regulatory T and regulatory B cells, triggering their suppression of Th cell activity. Here we use a human IL-12 bioactivity reporter cell line, protein binding assays, and primary human Th cells to demonstrate an additional mechanism by which IL-35 suppresses Th cell activity, wherein IL-35 directly inhibits the association of IL-12 with its surface receptor IL-12Rβ2 and downstream IL-12-dependent activities. IL-12 binding to the surface receptor IL-12Rβ1 was unaffected by IL-35. These data demonstrate that in addition to acting via regulatory T and regulatory B cells, human IL-35 can also directly suppress IL-12 bioactivity and its interaction with IL-12Rβ2.

Immunomodulatory effect of IL-35 gene-transfected mesenchymal stem cells on allergic asthma

Asthma is a common respiratory disease that has no definitive treatment at now. Immune response shifting from T helper (Th)1 to the Th2 is a main problem in asthma, and immunomodulation can help to control asthma. IL-35 and mesenchymal stem cells (MSCs) have regulatory effect on the immune system and may have the ability to control asthma pathology. After culturing MSCs, expression vector of IL-35 (pUNO1-mIL35elasti) was transduced to the MSCs, and then, asthmatic mice were treated with MSCs, MSCs-vector, MSCs-vector-IL-35, and no treatment. Airway hyperresponsiveness (AHR), levels of the cytokines, total and ovalbumin (OVA) specific immunoglobulin (Ig)E, LTB4, and LTC4 were measured. Lung tissue histopathology was also done. MSCs were successfully transduced by pUNO1-mIL35elasti vector, and IL-35 was produced in transduced cells. AHR, levels of the cytokines, IgEs, LTs, goblet cell hyperplasia, mucus secretion, peribronchial, and perivascular inflammation were controlled by MSCs therapy. In MSCs-IL-35 group, these controls were stronger than MSCs without IL-35 group. MSCs had strong effect on control of asthma. Transfected MSCs by expressing IL-35 gene could significantly better control allergic asthma symptoms than MSCs without IL-35. In the future, identification of the IL-35 mechanism of action would be useful to improve cytokine-cell based therapies.

Immune checkpoint molecules in prevention and development of asthma

Allergic asthma is a respiratory disease initiated by type-2 immune responses characterized by secretion of alarmins, interleukin-4 (IL-4), IL-5, and IL-13, eosinophilic inflammation, and airway hyperresponsiveness (AHR). Immune checkpoints (ICPs) are inhibitory or stimulatory molecules expressed on different immune cells, tumor cells, or other cell types that regulate immune system activation and maintain immune homeostasis. Compelling evidence indicates a key role for ICPs in both the progression and prevention of asthma. There is also evidence of asthma development or exacerbation in some cancer patients receiving ICP therapy. The aim of this review is to provide an updated overview of ICPs and their roles in asthma pathogenesis, and to assess their implications as therapeutic targets in asthma.

Evolutional perspective and functional characteristics of interleukin-17 in teleosts

Interleukin (IL)-17 is a proinflammatory cytokine and plays essential roles in adaptive and innate immune responses against bacterial and fungal infections. Especially in mammalian mucosal tissues, it is well known that innate immune responses via IL-17A and IL-17F, such as the production of antimicrobial peptides, are very important for microbiota control. In contrast, interesting insights into the functions of IL-17 have recently been reported in several teleost species, although little research has been conducted on teleost IL-17. In the present review, we focused on current insights on teleost IL-17 and speculated on the different or consensus parts of teleost IL-17 signaling compared to that of mammals. This review focuses on the role of teleost IL-17 in intestinal immunity. We expect that this review will encourage a further understanding of the roles and importance of IL-17 signaling in teleosts.

Pomegranate extract supplementation improves lung function parameters and IL-35 expression in participants with mild and moderate persistent allergic asthma: A randomized, double-blind, placebo-controlled trial

Existing asthma treatments are associated with side effects and limitations, which has led to an interest in alternative and complementary therapies. Given the anti-inflammatory properties of pomegranate, the present study aimed to determine the impact of pomegranate extract supplementation on lung function parameters evaluated through spirometry, high-sensitivity C-reactive protein (hs-CRP), pro-oxidant antioxidant balance, and interleukin 35) (IL-35) in participants with mild and moderate allergic asthma (based on forced expiratory volume in 1 second (FEV1) and clinical symptoms). Participants with mild and moderate allergic asthma (n = 64) were randomly assigned to two groups: the intervention group, which received two pomegranate extract capsules (500 mg/day), or the control group for eight weeks. Also, the physician prescribed similar drugs to the participants in the study. Independent samples T-test and Mann-Whitney U were used to compare the quantitative outcomes between the intervention group and the comparison group. The Wilcoxon test and the paired T-test were applied for within-group comparisons. A p-value <0.05 was considered significant. At the end of the study, the change levels of IL-35 in the intervention group increased significantly compared to the control group. In terms of the lung function parameters, FEV1/ forced vital capacity (FVC) (FEV1/FVC) ratio enhanced significantly in the intervention group compared to the control group. Also, the pomegranate extract significantly improved forced expiratory flow 25-75% (FEF25-75%), FEV1/FVC ratio, and FEV1 in the intervention group. No significant changes in FEV1 values were observed between the two groups at the end of the study. Also, no significant changes were seen in other indicators. It seems that pomegranate extract can improve lung function parameters and IL-35 expression in mild and moderate allergic asthma.

Clinical trial registration

https://www.irct.ir/trial/45612; identifier: IRCT20200205046384N1.

Interleukin-35 in autoimmune dermatoses: Current concepts

Interleukin-35 (IL-35) is a lately observed cytokine and is part of the IL-12 cytokine family. IL-35 includes two subunits, p35 and Epstein-Barr virus-induced gene 3, and activates subsequent signaling pathways by binding to receptors to mediate signal transduction, thereby modulating the immunoregulatory functions of T cells, B cells, macrophages, and other immune cell types. Although there is currently limited research on the roles of IL-35 in human autoimmunity, many studies have demonstrated that IL-35 may mediate immunosuppression. Therefore, it plays an essential role in some autoimmune dermatoses, including systemic lupus erythematosus, psoriasis, systemic sclerosis, and dermatomyositis. We will introduce the structure and biological characteristics of IL-35 and summarize its effects on the occurrence and development of autoimmune dermatoses in this article. It is suggested that IL-35 is a possible target for therapy in the aforementioned diseases.

Effector functions of Th17 cells are regulated by IL-35 and TGF-β in visceral leishmaniasis

Visceral leishmaniasis (VL) is a debilitating human pathogenesis in which the body's immune functions are severely compromised. Various subsets of T cells, including Th17 cells are important regulators of immune responses observed in various pathologies. The role of Th17 cells and its correlation with immuno-regulatory cytokines are however not well understood in human VL. Herein we studied how IL-17 is associated with the progression of Leishmania donovani infection using murine model of VL. We found induction of a strong IL-17 response at the early phase of infection which progressively reduced to basal level during chronic VL. The mechanistic study of this behavior was found to be linked with the role of regulatory T cells (CD4⁺ CD25⁺ T cells) that suppresses the proliferation of the Th17 cell population. Moreover, TGF-β and IL-35 derived from CD4⁺ CD25⁺ T cells are the key mediators for the downregulation of IL-17 during chronic VL. Thus, this study points to an antagonistic effect of Tregs and Th17 cells that can be used for designing better therapeutic and preventive strategies against leishmaniasis.

Reduced IL-35 in patients with immune thrombocytopenia

: The occurrence and development of primary immune thrombocytopenia is closely related to autoimmune imbalanced. Thus, we conducted the current study to investigate the modulation of IL-35, a newly identified immunological self-tolerance factor on immune thrombocytopenic purpura (ITP). We were enrolled peripheral blood in 21 adult healthy volunteers, 21 active primary ITP patients and 16 ITP patients in remission. In the same period, bone marrow plasma was drawn from active primary ITP patients and 16 bone marrow donors. Enzyme-linked immunoassay was used to measure IL-35 levels in bone marrow mononuclear cells and peripheral blood mononuclear cells. Real-time quantitative PCR was used to study the mRNA expression levels of p35, Epstein-Barr virus-induced gene 3 in bone marrow mononuclear cells and peripheral blood mononuclear cells. Compared with the normal group, IL-35 levels of in ITP patients were decreased significantly. IL-35 level in bone marrow plasma was decreased more significantly than that in peripheral blood plasma at the same stage. The results showed that plasma IL-35 levels were significantly decreased in patients with active ITP compared with those of control individuals, and IL-35 levels in bone marrow plasma were decreased more significantly compared with those at the same stage. The pathogenesis of ITP is associated with decreased IL-35 levels. Further studies are needed to expand sample content and explore more in-depth investigate a possible role of IL-35 in the pathogenesis and course of ITP.

Antigen-Specific Regulatory T Cell Therapy in Autoimmune Diseases and Transplantation

Regulatory T (Treg) cells are a heterogenous population of immunosuppressive T cells whose therapeutic potential for the treatment of autoimmune diseases and graft rejection is currently being explored. While clinical trial results thus far support the safety and efficacy of adoptive therapies using polyclonal Treg cells, some studies suggest that antigen-specific Treg cells are more potent in regulating and improving immune tolerance in a disease-specific manner. Hence, several approaches to generate and/or expand antigen-specific Treg cells in vitro or in vivo are currently under investigation. However, antigen-specific Treg cell therapies face additional challenges that require further consideration, including the identification of disease-relevant antigens as well as the in vivo stability and migratory behavior of Treg cells following transfer. In this review, we discuss these approaches and the potential limitations and describe prospective strategies to enhance the efficacy of antigen-specific Treg cell treatments in autoimmunity and transplantation.

Old Friends with Unexploited Perspectives: Current Advances in Mesenchymal Stem Cell-Based Therapies in Asthma

Mesenchymal stem cells (MSCs) have a great regenerative and immunomodulatory potential that was successfully tested in numerous pre-clinical and clinical studies of various degenerative, hematological and inflammatory disorders. Over the last few decades, substantial immunoregulatory effects of MSC treatment were widely observed in different experimental models of asthma. Therefore, it is tempting to speculate that stem cell-based treatment could become an attractive means to better suppress asthmatic airway inflammation, especially in subjects resistant to currently available anti-inflammatory therapies. In this review, we discuss mechanisms accounting for potent immunosuppressive properties of MSCs and the rationale for their use in asthma. We describe in detail an intriguing interplay between MSCs and other crucial players in the immune system as well as lung microenvironment. Finally, we reveal the potential of MSCs in maintaining airway epithelial integrity and alleviating lung remodeling.

Inflammatory versus Anti-inflammatory Profiles in Major Depressive Disorders-The Role of IL-17, IL-21, IL-23, IL-35 and Foxp3

Background: The authors of this research study intended to verify whether there are any changes in gene expression in depressed patients without coexisting inflammatory diseases for selected immune-inflammatory factors that are particularly important in autoimmune disease pathogenesis (IL-17, IL-21, IL-23, IL-35, Foxp3). Methods: The study was carried out on a group of 190 patients with depression and 100 healthy volunteers. The severity of depressive symptoms was assessed using the Hamilton Depression Scale. RT-PCR was used to evaluate mRNA expression and ELISA was used to measure protein expression of these genes. Results: The level of gene expression for IL-17, IL-21, IL-23, and IL-35 was substantially higher in the group of patients with depression compared to the control group. The mean mRNA expression of Foxp3 was considerably reduced in patients suffering from depressive disorders. There was a statistically significant correlation between the number of hospitalizations and the expression of specific inflammatory factors. Conclusions: Expression of specific inflammatory genes may be a factor in the etiopathogenesis of depressive disorders. The duration of the disease seems to be more important for the expression of the genes in question than the severity of depression. These cytokines may affect the metabolism of neurotransmitters and neuroendocrine functions in the brain as well as be a marker and a new potential therapeutic target for recurrent depressive disorders.

Interleukin-33 activates regulatory T cells to suppress innate γδ T cell responses in the lung

Foxp3⁺ regulatory T (T_reg) cells expressing the interleukin (IL)-33 receptor ST2 mediate tissue repair in response to IL-33. Whether T_reg cells also respond to the alarmin IL-33 to regulate specific aspects of the immune response is not known. Here we describe an unexpected function of ST2⁺ T_reg cells in suppressing the innate immune response in the lung to environmental allergens without altering the adaptive immune response. Following allergen exposure, ST2⁺ T_reg cells were activated by IL-33 to suppress IL-17-producing γδ T cells. ST2 signaling in T_reg cells induced Ebi3, a component of the heterodimeric cytokine IL-35 that was required for T_reg cell-mediated suppression of γδ T cells. This response resulted in fewer eosinophil-attracting chemokines and reduced eosinophil recruitment into the lung, which was beneficial to the host in reducing allergen-induced inflammation. Thus, we define a fundamental role for ST2⁺ T_reg cells in the lung as a negative regulator of the early innate γδ T cell response to mucosal injury.

Interleukin-35 regulates the balance of Th17 and Treg responses during the pathogenesis of connective tissue diseases

Interleukin (IL)-35 belongs to the IL-12 cytokine family and is a heterodimer of the p35 and Epstein-Barr virus-induced gene 3 (EBI3) subunits. Functionally, IL-35 can promote the proliferation and activation of regulatory T cells (Tregs) and suppress the function of T helper 17 (Th17) cells and other inflammatory cells to inhibit immune responses. In recent years, an abnormal IL-35 expression causing a Th17/Treg imbalance has been associated with the development and progression of several connective tissue diseases (CTDs), such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis (DM)/polymyositis (PM), and primary Sjögren's syndrome (pSS). Here, we review the role of IL-35 in regulating the balance of Th17/Treg responses in different types of CTDs and provide new insights into the role of IL-35 in these diseases.

ICOS+ Tregs: A Functional Subset of Tregs in Immune Diseases

Recent studies have reported the pathological effect of ICOS⁺ T cells, but ICOS signals also widely participate in anti-inflammatory responses, particularly ICOS⁺ regulatory T (Treg) cells. The ICOS signaling pathway endows Tregs with increased generation, proliferation, and survival abilities. Furthermore, there is enough evidence to suggest a superior capacity of ICOS⁺ Tregs, which is partly attributable to IL-10 induced by ICOS, yet the associated mechanism needs further investigation. In this review, we discuss the complicated role of ICOS⁺ Tregs in several classical autoimmune diseases, allergic diseases, and cancers and investigate the related therapeutic applications in these diseases. Moreover, we identify ICOS as a potential biomarker for disease treatment and prognostic prediction. In addition, we believe that anti-ICOS/ICOSL monoclonal antibodies exhibit excellent clinical application potential. A thorough understanding of the effect of ICOS⁺ Tregs and the holistic role of ICOS toward the immune system will help to improve the therapeutic schedule of diseases.

The effects of phenanthrene exposure on Treg and Th17 cells related cytokines in female rats

Phenanthrene (Phe) female rat model was established to explore the mechanism of Phe on immune impairment. The rats were randomly divided into three groups, including control (C), low (L), and high (H) groups. Phe was supplied to L and H groups at the dose of 180 and 900 mg/kg orally at first day and with the dose of 90 and 450 mg/kg by intraperitoneal injection at the last 2 days. The C group was enriched with the same volume of corn oil. The liver tissue was collected. Then, the protein and mRNA expressions of interleukin (IL)-35 and the concentration IL-17 were detected to evaluate the function of regulatory T cells (Treg cells) and T helper 17 cells (Th17 cells). In addition, IL-1β and interferon-γ (IFN-γ) were analyzed to evaluate the immune impairment. The results showed that the protein and mRNA expressions of IL-35 decreased significantly in H groups (P < 0.05). Meanwhile, there were significant increases in IL-17, IFN-γ and IL-1β in the liver of H group (P < 0.05). This study demonstrated that Phe exposure might be associated with the immune impairment via changing inflammatory mediators including IL-35 and IL-17 in female rats.

Role of Environmental Adjuvants in Asthma Development

PURPOSE OF REVIEW

This review summarizes recent progress in our understanding how environmental adjuvants promote the development of asthma.

RECENT FINDINGS

Asthma is a heterogeneous set of lung pathologies with overlapping features. Human studies and animal models suggest that exposure to different environmental adjuvants activate distinct immune pathways, which in turn give rise to distinct forms, or endotypes, of allergic asthma. Depending on their concentrations, inhaled TLR ligands can activate either type 2 inflammation, or Th17 differentiation, along with regulatory responses that function to attenuate inflammation. By contrast, a different category of environmental adjuvants, proteases, activate distinct immune pathways and prime predominantly type 2 immune responses. Asthma is not a single disease, but rather a group of pathologies with overlapping features. Different endotypes of asthma likely arise from perturbations of distinct immunologic pathways during allergic sensitization.

Serum IL-35 Levels Are Associated With Activity and Progression of Sarcoidosis

Objective: To investigate the relationship of interleukin (IL)-35 with sarcoidosis.

Methods: We enrolled 114 inpatients and outpatients with sarcoidosis at the Shanghai Pulmonary Hospital, and 24 healthy controls between March 2015 and December 2017. Serum and whole blood were collected during the follow-up period. Serum IL-35 levels were detected by ELISA. Proportions of Breg, Tfh, and Treg cells in the peripheral blood were detected using flow cytometry (FCM). The mRNA levels of p35, EBI3, and GAPDH in CD19⁺ cells and CD4⁺ cells were detected by real-time PCR. Sarcoidosis granuloma mice models were established with Propionibacterium acnes (PA) and one group was treated with IL-35 antibodies. Proportions of Breg, Tfh, and Treg cells in the peripheral blood and bronchoalveolar lavage fluid (BALF) were detected by FCM.

Results: The IL-35 levels and the proportions of Breg and Tfh cells in the peripheral blood of patients with active sarcoidosis were significantly higher compared to patients with stable sarcoidosis and healthy controls. Moreover, the IL-35 level in patients with progressive disease was lower than that found at the initial visit. EBI3 and p35 mRNA levels in CD19⁺ cells for patients with active sarcoidosis were significantly higher as compared to patients with stable sarcoidosis and healthy controls, while there were no significant differences in p35 and EBI3 mRNA levels in CD4⁺ cells between the three groups. In the mouse model of sarcoidosis, there were loose granulomata (macrophage accumulation in the bronchial areas and immature granuloma) after intervention with IL-35 antibodies. Meanwhile, the proportions of Breg cells in the peripheral blood and BALF of the model were significantly increased, while the proportion of Treg cells declined significantly. After intervention with IL-35 antibodies, the proportion of Breg cells in the peripheral blood of mice decreased significantly as compared to the mice not exposed to anti-IL-35 antibodies.

Conclusion: IL-35 levels increased significantly in the serum of patients with active sarcoidosis, and lower IL-35 levels were correlated with persistent disease. Serum IL-35 levels might be better correlated with Breg cell functions.

Expression imbalance of IL-17/IL-35 in peripheral blood and placental tissue of pregnant women in preeclampsia

OBJECTIVES

The possible mechanism of preeclampsia is investigated in this study to facilitate the exploration of the future remediation of this disease by analysing the changes of IL-17 and IL-35 in peripheral blood and placental tissue of pregnant women with preeclampsia (PE).

MATERIALS AND METHODS

The study was conducted using 45 healthy pregnant women as the control group and 90 pregnant women in the preeclampsia group, including 45 cases with severe preeclampsia and 45 cases with mild preeclampsia. All of 135 pregnant women underwent caesarean delivery. IL-17 and IL-35 concentrations in the serum were measured by ELISA, and IL-17 and IL-35 expression in placental specimens was detected by immunohistochemistry.

RESULTS

There were no statistically significant differences in age among the three study groups. Serum IL-17 levels were significantly higher in PE patients than in healthy pregnant women (P < 0.01). The ratio of positive staining for IL-17 was markedly higher in mild PE tissues (84.44%; 38/45) and severe PE tissues (86.67%; 39/45) than in healthy pregnant tissues (35.56%; 16/45) (P < 0.01). The strong positive rates for IL-17 were markedly higher in mild PE tissues (48.89%; 22/45) and severe PE tissues (68.89%; 31/45) than in healthy pregnant tissues (13.33%; 6/45) (P < 0.01). No differences between mild PE tissues and severe PE tissues were noted in both positive case rates and strong positive rates. Consistent with this finding, the ratio of strong positive staining for IL-35 was higher in healthy pregnant tissues (66.67%; 30/45) than in mild PE tissues (33.11%; 14/45) and severe PE tissues (26.67%; 12/45) (P < 0.01).

CONCLUSIONS

The abnormal increase in serum and placental of IL-17 has an association with the formation and development of PE. IL-35 expression is significantly lower in severe PE placenta tissue and serum compared with normal pregnant women. These results suggested that IL-17/IL-35 imbalance may play a role in the pathophysiology of PE.

Green propolis increases myeloid suppressor cells and CD4+Foxp3+ cells and reduces Th2 inflammation in the lungs after allergen exposure

ETHNOPHARMACOLOGICAL RELEVANCE

Propolis is a natural product produced by honeybees used as a medicine at least to 300 BC. In the last decades, several studies showed biological and pharmacological properties of propolis, witch scientifically explains the empirical use for centuries. The anti-inflammatory activity of propolis with the purpose to reduce Th2 inflammation has been evaluated in allergic asthma. However, it remains to be determined how propolis negatively regulates the immune response after allergen re-exposure.

AIM OF THE STUDY

We hypothesized that the anti-inflammatory activity of propolis is dependent on the induction of myeloid derived suppressor cells (MDSC) and regulatory T cells.

MATERIALS AND METHODS

To assess this hypothesis, we used an ovalbumin-induced asthma model to evaluate the effect of EPP-AF® dry extract from Brazilian green propolis.

RESULTS

Propolis treatment decreased pulmonary inflammation and mucus production as well as eosinophils and IL-5 in the broncoalveolar lavage. Propolis enhanced also in vitro differentiation and in vivo frequency of lung MDSC and CD4⁺Foxp3⁺ regulatory T cells.

CONCLUSIONS

Together these results confirm the immunomodulatory potential of propolis during sensitization and challenge with allergen. In addition, the collecting findings show, for the first time, that propolis increases the frequency of MDSC and CD4⁺Foxp3⁺ regulatory T cells in the lungs, and suggest that it could be use as target for development of new immunotherapy or adjuvant immunotherapy for asthma.

Different expression levels of interleukin-35 in asthma phenotypes

Background

Interleukin (IL)-35 is a newly discovered inhibitory cytokine which is produced by regulatory B and T lymphocytes and belongs to the IL-12 family. It plays a suppressive role in human inflammatory diseases; however, its role in asthma phenotypes is unclear. Our study focuses on the sputum IL-35 level in patients and investigates different airway inflammation capacities of sputum IL-35 in patients with different asthma phenotypes.

Objective

We aimed to determine the sputum IL-35 levels in asthmatic patients with clinical remission phenotypes and control subjects and to investigate possible correlations among lung function, age, sex, fractional exhaled nitric oxide (FeNO), and smoking history in these phenotypes.

Methods

Sputum samples were collected from patients with clinical asthma remission (n = 89, 37 males, age 52.24 ± 13.32 years) and a healthy control group (n = 19, 9 males, age 44.58 ± 16.3 years). All subjects underwent sputum induction. Induced sputum was assessed for inflammatory cell count, and sputum levels of IL-35 and other cytokines were measured by ELISA and Cytometric Bead Array, respectively.

Results

Sputum IL-35 (median (q1, q3)) levels showed no significant difference between asthma patients (4.89 ng/mL (2.97, 22.75)) and healthy controls (6.01 ng/mL (4.09, 30.47)). However, the sputum IL-35 level was significantly reduced in patients with eosinophilic asthma (EA) (3.95 ng/mL (2.80, 11.00)) compared to patients with neutrophilic asthma (NA) (40.59 ng/mL (20.59, 65.06), p = 0.002), paucigranulocytic asthma (PA) (6.25 ng/mL (3.10, 24.60), p = 0.012), and mixed granulocytic asthma (MA) (22.54 ng/mL (2.58, 52.45), p = 0.026). IL-35 levels in sputum showed a positive correlation with sputum neutrophil cells and a negative correlation with FeNO, FEV1% predicted, and FVC predicted. Furthermore, sputum IL-35 had a significant positive association with Th1-related factors and a negative correlation with Th2-related factors.

Conclusions

Sputum IL-35 is likely involved in different pathophysiological mechanisms of NA and EA and exerts different effects in asthma phenotypes.

Interleukin-35 inhibits human umbilical vein endothelial cell injury induced by sera from pre-eclampsia patients by up-regulating S100A8 protein expression

Objectives: The protective effects of interleukin(IL)-35 against injury to human umbilical vein endothelial cells (HUVECs) induced by the serum of pre-eclampsia patients were analyzed.Methods: This cross-sectional study included 24 patients with pre-eclampsia (PE) and 24 normotensive pregnant women.Results: Compared to normotensive pregnant women, patients with pre-eclampsia had lower IL-35 levels (P < 0.05). In addition, our in vitro experiments, IL-35 inhibited the PE serum-induced apoptosis of HUVECs and the levels of reactive oxygen species in HUVECs.Conclusion: Decreases in the serum IL-35 level may play an important role in the pathogenesis of endothelial dysfunction in patients with pre-eclampsia.

Elevated Th17 cell frequencies and Th17/Treg ratio are associated with airway hyperresponsiveness in asthmatic children

Introduction: The elevation of T helper (Th)17 cell frequencies and the imbalance of Th17/regulatory T (Treg) cells occur in asthma pathogenesis. Airway hyperresponsiveness (AHR) is a cardinal feature of asthma, and Th17 responses can promote AHR. We hypothesized that changes in Th17 cells and the Th17/Treg ratio correlate with AHR in asthmatic children.Methods: Twenty asthmatic children and twenty healthy children were included in the study. The peak expiratory flow (PEF) % pred, forced expiratory volume in 1 s (FEV₁) % pred and the FEV₁/forced vital capacity (FVC) ratio were measured in all subjects. Methacholine challenge test (MCT) was performed in asthmatic children. Flow cytometric analysis was used to determine the proportions of Th17 and Treg cells in peripheral blood mononuclear cells. ELISA was used to assess serum levels of interleukin (IL)-17A and IL-10.Results: Th17 cell frequencies (2.272 ± 0.207% in asthmatics, 1.193 ± 0.131% in controls, P < 0.01) and Th17/Treg ratios (0.371 ± 0.0387 in asthmatics, 0.183 ± 0.020 in controls, P < 0.01) were significantly increased in asthmatic children compared to controls. In asthmatic children, the MCT grade had positive correlations with the Th17 cell frequencies [r = 0.718, P < 0.01], serum IL-17A level [r = 0.753, P < 0.01] and Th17/Treg ratio [r = 0.721, P < 0.01], while the log₁₀PD20-FEV₁ value was negatively correlated with the Th17 cell frequencies [r = -0.654, P < 0.01], serum IL-17A level [r = -0.652, P < 0.01] and Th17/Treg ratio [r = -0.625, P < 0.01].Conclusion: Th17 cell, IL-17A and Th17/Treg ratio were positively correlated with AHR in asthmatic children. It may be helpful to monitor Th17 cells and the Th17/Treg ratio as indicators of AHR in clinical practice.

Interleukin-35 sensitizes monocytes from patients with asthma to glucocorticoid therapy by regulating p38 MAPK

The activation of monocytes and macrophages is associated with steroid-resistant (SR) asthma. Interleukin-35 (IL-35) is an important anti-inflammatory cytokine, but its regulatory effects on monocytes in patients with SR asthma is not fully understood. Based on clinical response to oral prednisolone, 34 patients with steroid-sensitive (SS) asthma and 20 patients with SR asthma were enrolled in the present study. Serum IL-35 levels were analyzed using the Luminex 200 platform. Monocytes from patients with asthma were pretreated with IL-35 followed by dexamethasone (DEX) and lipopolysaccharide (LPS), then corticosteroid sensitivity was evaluated according to the half-maximal inhibitory concentration of DEX with respect to LPS-induced IL-6 maximal production in monocytes (DEX-IC₅₀). The percentage of maximal inhibition of IL-6 by DEX was presented as E_max. Phosphorylated-P38 mitogen activated kinase (p-p38 MAPK) and mitogen-activated protein kinase phosphatase-1 (MKP-1) were examined by flow cytometry and reverse transcription-quantitative PCR analysis, respectively. Glucocorticoid receptor (GR) binding to the glucocorticoid response element (GRE) was assessed by chromatin immunoprecipitation. Compared with patients with SS asthma, patients with SR asthma had lower IL-35 expression levels (P<0.05). Correlation analysis results demonstrated that the expression levels of IL-35 showed a weak negative correlation with log DEX-IC₅₀ (r=-0.351; P<0.01) and a moderate positive correlation with E_max value (r=0.4501; P<0.01) in all patients with asthma. Moreover, IL-35 enhanced DEX-suppressed IL-6 production and the DEX-induced upregulation of the MKP-1 mRNA expression level in monocytes from both patient groups (P<0.01). In addition, IL-35 inhibited p-p38 MAPK expression in monocytes, and these effects were mediated via an increase in DEX-induced GR binding to GRE. Therefore, IL-35 may be involved in the corticosteroid enhancing effects in monocytes of patients with SR and SS asthma, suggesting potential benefits of IL-35 supplementation in asthmatics with DEX.

IL-35 is critical in suppressing superantigenic Staphylococcus aureus-driven inflammatory Th17 responses in human nasopharynx-associated lymphoid tissue

The human nasopharynx is frequently exposed to microbial pathogens, including superantigen-producing Staphylococcus aureus (SAg-Sau), which activates potent pro-inflammatory T cell responses. However, cellular mechanisms that control SAg-Sau-driven T cell activation are poorly understood. Using human nasopharynx-associated lymphoid tissue (NALT), we show that SAg-Sau drove a strong Th17 activation, which was associated with an impaired CD4⁺ T cell-mediated immune regulation. This impairment of immune control correlated with a significant downregulation of interleukin-35 (IL-35) expression in tonsillar CD4⁺ T cells by SAg-Sau. Supplementing recombinant IL-35 suppressed SAg-Sau-activated Th17 responses, and this IL-35-mediated suppression positively correlated with the level of Th17 activation. Interestingly, SAg-Sau stimulation induced Foxp3⁺ Treg expansion and interleukin-10 (IL-10) production, which effectively suppressed the Th1 response, but failed to control the activation of Th17 cells. Overall, our results reveal an aberrant T cell regulation on SAg-Sau-driven Th17 activation and identify IL-35 as a critical cytokine to control superantigenic S.aureus-activated Th17 responses.

Aberrant Th2 Immune Responses Are Associated With a Reduced Frequency of IL-35-Induced Regulatory T Cells After Allergen Exposure in Patients With Allergic Asthma

PURPOSE

Allergen exposure induces aberrant T helper (Th) 2 immune responses in patients with allergic asthma, but not in sensitized asymptomatic and nonallergic subjects. Interleukin (IL)-35-induced regulatory T (iTr35) cells are a new subset of regulatory T cells with immunoregulatory properties. These cells can significantly suppress Th2 responses in seasonal allergic rhinitis. However, it remains unknown whether iTr35 cells are involved in the immunoregulation of allergic asthmatic individuals after specific allergen exposure.

METHODS

The iTr35 cell frequency in peripheral blood mononuclear cells (PBMCs) was measured in patients with allergic asthma as well as in asymptomatic and healthy subjects. The difference in naïve CD4⁺ T cell conversion to iTr35 cells in vitro during allergen stimulation was also investigated. The effects of iTr35 cells on naïve CD4⁺ T cell differentiation into Th2 cells, CD4⁺CD25^- T (Teff) cell proliferation and Th2 cytokine production in vitro were assessed.

RESULTS

Significantly reduced iTr35 cell frequencies and IL-35 expression levels were found in asthmatic patients with Derp1 allergy compared with asymptomatic and healthy subjects. Moreover, the circulating iTr35 cell proportion and IL-35 expression level in asthmatic patients gradually decreased with disease severity. Patients with allergic asthma had reduced transformation of naïve CD4⁺ T cells into iTr35 cells and IL-35 production after allergen exposure compared with asymptomatic and healthy subjects. Most importantly, iTr35 cells inhibited allergen-driven differentiation of naïve CD4⁺ T cells into Th2 cells, Teff cell proliferation and Th2 cytokine production in an IL-35-dependent manner.

CONCLUSIONS

The results of our study suggest that iTr35 cells may play an important role in preventing Th2 responses to allergens by secreting IL-35 and that iTr35 cells may be a potential new immune regulator of allergic asthma.

BAFF gene silencing attenuates allergic airway inflammation by promoting the generation of Tregs via activating pro-Treg cytokines

AIMS

Allergic airway inflammation is one of the major pathological events involved in asthma, and dysregulation of regulatory T cells (Treg) plays a crucial role in the development of allergic airway inflammation. Here, we attempted to investigate the regulatory effects of B cell-activating factor (BAFF) on Tregs in allergic airway inflammation.

MAIN METHODS

BAFF expression was analyzed by ELISA, quantitative reverse transcription PCR (RT-PCR) and Western blot assays. The levels of IL-4, TGF-β, IL-2, and IL-10 were tested using ELISA kits. Flow cytometry was conducted to analyze the populations of CTLA4⁺ Foxp3⁺ Tregs.

KEY FINDINGS

BAFF was found to be aberrantly expressed in sputum and lungs in patients with asthma as well as OVA sensitized mice. BAFF silencing by lentiviral BAFF shRNA reduced the number of eosinophils and levels of IL-4 in the BAL fluid, as well as the Fizz1 expression in the lungs of OVA mice. Additionally, the population of CTLA4⁺ Foxp3⁺ Tregs were significantly decreased in OVA mice and had a negative correlation to BAFF levels in asthmatic patients and OVA mice. BAFF silencing in vivo increased levels of CTLA4⁺ Foxp3⁺ Tregs and the secretion of IL-10, and improved the regulatory phenotype and suppressor function of Tregs in vitro. Furthermore, BAFF can affect Tregs generation by regulating the production of the pro-Treg cytokines IL-2 and TGF-β.

SIGNIFICANCE

BAFF has an inhibitory effect on the generation and suppressor function of Tregs by affecting pro-Tregs cytokines, thereby contributing to the development of allergic airway inflammation.

Cancer Immunotherapies Targeting Tumor-Associated Regulatory T Cells

Tumor-associated regulatory T cells (Tregs) are important effectors in the tumor microenvironment (TME), acting as accomplices in the promotion of tumor progression. Currently, the importance of removing the immunosuppressive activity in the TME has received its due attention, and Tregs have been focused on. The cytokine-receptor axes are among the essential signaling pathways in immunocytes, and tumor-associated Tregs are no exception. Therefore, manipulating cytokine-receptor pathways may be a promising effective strategy for treating various malignancies. Here, we summarize the classification, immunosuppressive mechanisms, existing immunotherapies, and potential biomarkers related to tumor-infiltrating Tregs to guide the development of effective cancer immunotherapies.

Interleukin-35 as an Emerging Player in Tumor Microenvironment

IL-35 is the newest member of IL-12 family. A dimeric protein consisting of two separate subunits has manifested suppressive actions on immune system, which is counterproductive in the context of cancers. Various reports have confirmed its inhibitory role on immune system which is carried out via formation of IL-35-producing regulatory T cells (iTr35), increased Treg development and suppressive Th17 cells growth. Although last decade has seen a great deal of scientific interest on this subject, the exact role, precise signal transduction and elaborative functions of IL-35 in tumor microenvironment (TME) remained elusive. Search for anti-IL-35 therapies have exhibited limited success in animal models. Contrarily, few studies have denied the idea that IL-35 plays a role in cancer. The purpose of this review is to analyze the reported scientific data on continuous symphony of IL-35 in cancers since the inception of former.

Interleukin-35 in immune-related diseases: protection or destruction

Interleukin-35 (IL-35) is a recently identified heterodimeric cytokine in the IL-12 family. It consists of an IL-12 subunit α chain (P35) and IL-27 subunit Epstein-Barr virus-induced gene 3 (EBI3) β chain. Unlike the other IL-12 family members, it signals through four unconventional receptors: IL-12Rβ2-IL-27Rα, IL-12Rβ2-IL-12Rβ2, IL-12Rβ2-GP130, and GP130-GP130. Interleukin-35 signaling is mainly carried out through the signal transducer and activator of transcription family of proteins. It is secreted not only by regulatory T (Treg) cells, but also by CD8+ Treg cells, activated dendritic cells and regulatory B cells. It exhibits immunosuppressive functions distinct from those of other members of the IL-12 family; these are mediated primarily by the inhibition of T helper type 17 cell differentiation and promotion of Treg cell proliferation. Interleukin-35 plays a critical role in several immune-associated diseases, such as autoimmune diseases and viral and bacterial infections, as well as in tumors. In this review, we summarize the structure and function of IL-35, describe its role in immune-related disorders, and discuss the mechanisms by which it regulates the development and progression of diseases, including inflammatory bowel disease, collagen-induced arthritis, allergic airway disease, hepatitis, and tumors. The recent research on IL-35, combined with improved techniques of studying receptors and signal transduction pathways, allows for consideration of IL-35 as a novel immunotherapy target.

Association between Interleukin 35 Gene Single Nucleotide Polymorphisms and Systemic Lupus Erythematosus in a Chinese Han Population

Interleukin-35 (IL-35) exerts crucial roles in the pathogenesis and development of systemic lupus erythematosus (SLE), in this study we aim to explore the associations between IL-35 gene polymorphisms and the susceptibility, clinical features and plasma IL-35 levels of SLE patients, respectively. 490 SLE patients and 489 healthy controls were recruited in our study. The correlations between the polymorphisms of seven SNPs of IL-35 encoding gene and the susceptibility, main clinical manifestations of SLE were evaluated, respectively. Plasma IL-35 levels were assessed in 76 SLE patients, and the associations between plasma IL-35 levels and the polymorphisms of genotyped SNPs were explored. There were significant associations between the polymorphisms of rs4740 and the occurrence of renal disorder, hematological disorder in SLE patients, respectively (p = 0.001; p = 0.001). In addition, there were no significant associations observed between the genotype frequencies of genotyped SNPs and the risk of SLE, plasma IL-35 levels, respectively. The polymorphism of rs4740 of IL-35 encoding gene is associated with the occurrence of renal disorder and hematological disorder of SLE patients.

The Role of Interleukin-1 cytokine family (IL-1β, IL-37) and interleukin-12 cytokine family (IL-12, IL-35) in eumycetoma infection pathogenesis

Mycetoma is a neglected tropical disease, endemic in many tropical and subtropical regions, characterised by massive deformity and disability and can be fatal if untreated early and appropriately. Interleukins (IL) -35 and IL-37 are newly discovered cytokines that play an important role in suppressing the immune system. However, the expression of these interleukins in patients with Madurella mycetomatis (M. mycetomatis) induced eumycetoma has not yet been explored. The aim of this study is to determine the levels of IL-1 family (IL-1β, IL-37) and IL-12 family (IL-12, IL-35) in a group of these patients and the association between these cytokines levels and the patients’ demographic characteristics. The present, case-control study was conducted at the Mycetoma Research Centre, Soba University Hospital, University of Khartoum, Sudan and it included 140 individuals. They were divided into two groups; group I: healthy controls [n = 70; median age 25 years (range 12 to 70 years)]. Group II: mycetoma patients [n = 70 patients; median age 25 (range 13 to 70 years)]. Cytokines levels were measured in sera using enzyme linked immunosorbent assay (ELISA). There was a significant negative correlation between IL-1β and IL-12 levels and lesion size and disease duration, while IL-37 and IL-35 levels were significantly positively correlated with both lesion size and disease duration. The analysis of the risk factors of higher circulatory levels of IL-37 in patients of mycetoma showed a negative significant association with IL-1β cytokine, where a unit increment in IL-1β will decrease the levels of IL-37 by 35.28 pg/ml. The levels of IL-37 among the patients with a duration of mycetoma infection ≤ 1 year were significantly low by an average of 18.45 pg/ml compared to patients with a mycetoma infection’s duration of ≥ 5years (reference group). Furthermore, the risk factors of higher levels of IL-35 in mycetoma patients revealed a negative significant association with IL-12, as a unit increment in IL-12 decreases the levels of IL-35 by 8.99 pg/ml (p < 0.001). Levels of IL-35 among the patients with duration of mycetoma infection ≤ one year were significantly low on average by 41.82 pg/ml (p value = 0.002) compared to patients with a duration of mycetoma infection ≥ 5 years (reference group). In conclusion, this study indicates that both IL-35 and IL-37 are negatively associated with the levels of IL-1β and IL-12 in eumycetoma mycetoma infection; and high levels of IL-37 and IL-35 may have a negative impact on disease progression.

Mycetoma is a progressive chronic granulomatous fungal or bacterial infection that may result in massive destruction of subcutaneous tissues, muscles and bones. Mycetoma is a neglected disease which is endemic in many tropical and subtropical areas. If the disease is not treated properly, eventually it ends up with amputation and adverse medical, health and socioeconomic effects on patients and the community. Previous data suggested a crucial role of adaptive immunity in host resistance to causative agents and in the disease progress. The recently identified IL-35 and IL-37 cytokines revealed an important role in immune suppression. Nevertheless, the expression of these interleukins in patients with mycetoma has not yet been investigated. Therefore, the present case-control study aimed to determine the levels of IL-1 family (IL-1β, IL-37) and IL-12 family (IL-12, IL-35) in these patients and the association between these cytokines levels and the patients’ demographic characteristics. The results of this study showed that, the levels of IL-37 and IL-35 were consistently positively correlated with different diameters of mycetoma lesions as well as its duration. However, the levels of IL-1β and IL-12 were consistently negatively correlated with different diameters of lesions and the duration of mycetoma infection. The analysis of the risk factors of higher circulatory levels of IL-37 in patients of mycetoma showed a negative significant association with IL-1β cytokine Furthermore, the risk factors of higher levels of IL-35 in patients of mycetoma revealed a negative significant association with IL-12. These findings uncover a possible the role of IL-35 and IL-37 in the pathogenesis of mycetoma, and may declare their potential value in treatment of mycetoma.

Investigating the potential immune role of IL-35 in grass carp (Ctenopharyngodon idella)

Interleukin-35 (IL-35) is a member of the IL-12 cytokine family and a heterodimeric protein formed by Epstein-Barr virus-induced gene 3 (EBI3) and IL-12p35. Emerging evidence showed that IL-35 is a key player in the regulation of cellular communication, differentiation, and inflammation. To date, no studies on fish IL-35 have been documented. In this work, we first identify two splicing isoforms of EBI3, EBI3a and EBI3b, from grass carp (Ctenopharyngodon idella). EBI3a is composed of 299 amino acid residues and possesses an immunoglobulin-like (Ig-like) domain and a fibronectin type 3 (FN3) domain that is a conservative domain in vertebrate EBI3. However, the EBI3b is composed of 177 amino acid residues and only contains an Ig-like domain. The result of Co-immunoprecipitation suggests that only EBI3a can associate with IL-12p35 to form IL-35 in grass carp. Like the function of IL-35 in human and mouse, recombinant grass carp IL-35 protein could induce the expression of genes EBI3a, IL-12p35, and CD25-like and downregulate the expression of genes CD4-1, CD4-2, IL-17A/F1, and RORγ2. Taken together, these results indicate for the first time that a teleost IL-35 may also have the ability to induce regulatory T (Treg) cells, inhibit effector T (Teff) cell proliferation and restrict the differentiation and function of T helper 17 (Th17) cells in teleost.

Aberrant IL-35 levels in patients with primary Sjogren's syndrome

OBJECTIVE

IL-35 is a newly discovered immunoregulatory cytokine that possesses the ability to inhibit CD4 + effector T cells and alleviate autoimmune diseases. The objective of this study was to investigate IL-35 levels in patients with primary Sjogren's syndrome (pSS) and explore the roles of IL-35 in the pathogenesis of pSS.

METHODS

Thirty-four hospitalized patients with pSS were recruited, and 34 volunteers were enrolled as healthy controls. An ELISA was adopted to measure plasma IL-35 levels. The levels of P35 and EBI3 mRNAs in peripheral blood mononuclear cells (PBMCs) were determined using real-time quantitative PCR. The percentage of CD4 + EBI3 + T cells and CD19 + EBI3 + B cells was analysed using flow cytometry. Correlations between IL-35 levels, P35 and EBI3 mRNAs, numbers of CD4 + EBI3 + T cells, CD19 + EBI3 + B cells and clinical parameters were analysed.

RESULTS

Significantly lower plasma IL-35 levels, P35 and EBI3 mRNA levels, and percentages of CD4 + EBI3 + T cells but increased percentages of CD19 + EBI3 + B cells were observed in patients with pSS than in healthy controls. IL-35 levels, EBI3 mRNA expression and the percentage of CD4 + EBI3 + T cells exhibited negative correlations with the ESSDAI score, whereas levels of the IL-35 protein and EBI3 mRNA were negatively correlated with the ESR. Patients who were positive for anti-SSB antibodies presented with lower IL-35 levels and percentages of CD4 + EBI3 + T cells.

CONCLUSIONS

Based on these results, a decrease in the IL-35 levels may play an important role in the pathogenesis of pSS. IL-35 may act as a potential therapeutic agent against inflammation in patients with pSS.

Regulatory cytokine function in the respiratory tract

The respiratory tract is an important site of immune regulation; required to allow protective immunity against pathogens, while minimizing tissue damage and avoiding aberrant inflammatory responses to inhaled allergens. Several cell types work in concert to control pulmonary immune responses and maintain tolerance in the respiratory tract, including regulatory and effector T cells, airway and interstitial macrophages, dendritic cells and the airway epithelium. The cytokines transforming growth factor β, interleukin (IL-) 10, IL-27, and IL-35 are key coordinators of immune regulation in tissues such as the lung. Here, we discuss the role of these cytokines during respiratory infection and allergic airway disease, highlighting the critical importance of cellular source and immunological context for the effects of these cytokines in vivo.

The role of interleukins in preeclampsia: A comprehensive review

Preeclampsia is a multi-system hypertensive disorder of pregnancy, with significant rates of maternal and neonatal morbidity. It represents a major cause of preterm birth, as definitive treatment demands fetal delivery. Although its pathophysiology is complicated, placental hypoxia and endothelial dysfunction constitute established pathogenetic steps of the disease. Inflammation is considered to be a crucial mediator of preeclampsia process, as an imbalance between T_H 1, T_H 2, and T_H 17 immune responses is observed. The present review accumulates current knowledge about the contribution of interleukins in preeclampsia, summarizing the pathways through which each interleukin exerts its function in the disease. Also, the role of genetic polymorphisms is explored and the predictive efficacy of maternal serum interleukin levels is evaluated. Finally, recommendations about the safe interpretation of the outcomes, as well as guidance for future research, are provided.

Resolution of chronic inflammatory disease: universal and tissue-specific concepts

Inflammation and its resolution is under-studied in medicine despite being essential for understanding the development of chronic inflammatory disease. In this review article, we discuss the resolution of inflammation in both a biological and translational context. We introduce the concept of impaired resolution leading to diseases like rheumatoid arthritis, Crohn's disease, and asthma, as well as the cellular and molecular components that contribute to resolution of joint, gut, and lung inflammation, respectively. Finally, we discuss potential intervention strategies for fostering the resolution process, and their implications for the therapy of inflammatory diseases.

Role of IL-35 in sublingual allergen immunotherapy

BACKGROUND

Grass pollen-specific immunotherapy involves immunomodulation of allergen-specific T_H2 responses and induction of IL-10⁺ and/or TGF-β⁺CD4⁺CD25⁺ regulatory T cells (induced Treg cells). IL-35⁺CD4⁺CD25⁺ forkhead box protein 3-negative T (IL-35-inducible regulatory T [iT_R35]) cells have been reported as a novel subset of induced Treg cells with modulatory characteristics.

OBJECTIVE

We sought to investigate mechanisms underlying the induction and maintenance of immunologic tolerance induced by IL-35 and iT_R35 cells.

METHODS

The biological effects of IL-35 were assessed on group 2 innate lymphoid cells (ILC2s); dendritic cells primed with thymic stromal lymphopoietin, IL-25, and IL-33; and B and T_H2 cells by using flow cytometry and quantitative RT-PCR. Grass pollen-driven T_H2 cell proliferation and cytokine production were measured by using tritiated thymidine and Luminex MagPix, respectively. iT_R35 cells were quantified in patients with grass pollen allergy (seasonal allergic rhinitis [SAR] group, n = 16), sublingual immunotherapy (SLIT)-treated patients (SLIT group, n = 16), and nonatopic control subjects (NACs; NAC group, n = 16).

RESULTS

The SAR group had increased proportions of ILC2s (P = .002) and IL-5⁺ cells (P = .042), IL-13⁺ cells (P = .042), and IL-5⁺IL-13⁺ ILC2s (P = .003) compared with NACs. IL-35 inhibited IL-5 and IL-13 production by ILC2s in the presence of IL-25 or IL-33 (P = .031) and allergen-driven T_H2 cytokines by effector T cells. IL-35 inhibited CD40 ligand-, IL-4-, and IL-21-mediated IgE production by B cells (P = .015), allergen-driven T-cell proliferation (P = .001), and T_H2 cytokine production mediated by primed dendritic cells. iT_R35 cells suppressed T_H2 cell proliferation and cytokine production. In addition, allergen-driven IL-35 levels and iT_R35 cell counts were increased in patients receiving SLIT (all, P < .001) and NACs (all, P < .001) compared with patients with SAR.

CONCLUSION

IL-35 and iT_R35 cells are potential novel immune regulators induced by SLIT. The clinical relevance of SLIT can be underscored by restoration of protective iT_R35 cells.

Regulatory T Cells and Acute Lung Injury: Cytokines, Uncontrolled Inflammation, and Therapeutic Implications

Acute respiratory distress syndrome/acute lung injury (ALI) was described in 1967. The uncontrolled inflammation is a central issue of the syndrome. The regulatory T cells (Tregs), formerly known as suppressor T cells, are a subpopulation of T cells. Tregs indirectly limits immune inflammation-inflicted tissue damage by employing multiple mechanisms and creating the appropriate immune environment for successful tissue repair. And it plays a central role in the resolution of ALI. Accordingly, for this review, we will focus on Treg populations which are critical for inflammatory immunity of ALI, and the effect of interaction between Treg subsets and cytokines on ALI. And then explore the possibility of cytokines as beneficial factors in inflammation resolution of ALI.

Clinical Significance of Decreased Interleukin-35 Expression in Patients with Psoriasis

In psoriasis, a chronic, recurrent, inflammatory skin disease, CD4+T cells and their related cytokines play an important role in its pathogenesis. The role of interleukin (IL)-35, an immunosuppressive cytokine involved in many autoimmune diseases, is unclear in the pathogenesis of psoriasis. This study evaluated IL-35 expression and clinical significance in psoriasis. Protein and mRNA levels of specified markers were measured by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (qRT-PCR), respectively. Results showed that plasma IL-35 concentrations were lower in patients with psoriasis than in healthy individuals (Z = -6.525, P < .0001). Ebi3 and p35 showed lower mRNA levels in peripheral blood mononuclear cells from patients with psoriasis than in healthy individuals (Z = -5.078, P < .0001, Z = -2.609, P = .009, respectively). The areas under the receiver-operating characteristic (ROC) curves of IL-35, Ebi3, and p35 for patients with psoriasis versus the control were 0.86, 0.78, and 0.64, respectively. Pearson correlation analysis showed that plasma IL-35 expression negatively correlated with interferon-gamma, tumor necrosis factor-alpha, levels of IL-23, -17, and -22, or the Psoriasis Activity and Severity Index and positively correlated with levels of transforming growth factor beta and IL-10 levels in patients with psoriasis. Summarily, IL-35 might mediate psoriasis pathogenesis by influencing the expression of Th1/Th17/Treg -related cytokines and might be a putative target in monitoring or treating psoriasis.

Human iPSC-MSCs prevent steroid-resistant neutrophilic airway inflammation via modulating Th17 phenotypes

BACKGROUND

Human induced pluripotent stem cells-derived mesenchymal stem cells (iPSC-MSCs) have been shown to be effective in Type 2 helper T cells (Th2)-dominant eosinophilic allergic airway inflammation. However, the role of iPSC-MSCs in Type 17 helper T cells (Th17)-dominant neutrophilic airway inflammation remains poorly studied. Therefore, this study was to explore the effects of iPSC-MSCs on an experimental mouse model of steroid-resistant neutrophilic airway inflammation and further determine the underlying mechanisms.

METHODS

A mouse model of neutrophilic airway inflammation was established using ovalbumin (OVA) and lipopolysaccharide (LPS). Human iPSC-MSCs were systemically administered, and the lungs or bronchoalveolar lavage fluids (BALF) were collected at 4 h and 48 h post-challenge. The pathology and inflammatory cell infiltration, the T helper cells, T helper cells-associated cytokines, nuclear transcription factors and possible signaling pathways were evaluated. Human CD4⁺ T cells were polarized to T helper cells and the effects of iPSC-MSCs on the differentiation of T helper cells were determined.

RESULTS

We successfully induced the mouse model of Th17 dominant neutrophilic airway inflammation. Human iPSC-MSCs but not dexamethasone significantly prevented the neutrophilic airway inflammation and decreased the levels of Th17 cells, IL-17A and p-STAT3. The mRNA levels of Gata3 and RORγt were also decreased with the treatment of iPSC-MSCs. We further confirmed the suppressive effects of iPSC-MSCs on the differentiation of human T helper cells.

CONCLUSIONS

iPSC-MSCs showed therapeutic potentials in neutrophilic airway inflammation through the regulation on Th17 cells, suggesting that the iPSC-MSCs could be applied in the therapy for the asthma patients with steroid-resistant neutrophilic airway inflammation.

Oral Escherichia coli expressing IL-35 meliorates experimental colitis in mice

Background

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) characterized by chronic inflammation of colon. It is commonly believed that the imbalance of immune system and overwhelming production of cytokines are involved in the pathogenesis of UC. Recent studies demonstrated that interleukin-35 (IL-35), a key player in the regulation of inflammation, has been identified as potential therapeutic target to treat UC. However, conventional intravenous administration is costly and inconvenient. The present study was designed to establish a novel IL-35 delivery system and investigate its therapeutic effects on dextran sulfate sodium (DSS)-induced experimental colitis in mice for the first time.

Methods

An engineered Escherichia coli (E. coli/IL-35) expressing IL-35 was constructed. Adult male BALB/c mice randomly got the oral administration of E. coli/IL-35, empty plasmid-transformed E. coli (E. coli0) or PBS for treatment following ingestion of 3% DSS solution for 5 days. Normal mice were used as control group. Colonic and splenic tissues were collected on day 10 post-DSS-induction. Clinical signs, disease activity index (DAI), pathological and immunohistological changes, cytokine profiles and cell populations were evaluated.

Results

Intragastric administration of E. coli/IL-35 effectively protected the colitis mice from DSS assimilation including weight loss and colon shortening. Pathological analysis showed significantly lower DAI score and much less intra-colon infiltration of neutrophils and CD3⁺ cells in the IL-35 treated group. Moreover, E. coli/IL-35-treated mice demonstrated much less CD4⁺ IL-17A⁺ Th17 cells and a higher level of CD4⁺CD25⁺Foxp3⁺ Tregs in spleen and mesenteric lymph nodes, as well as increased colon and serum level of IL-10 and IL-35 and decreased levels of IL-6.

Conclusions

Our study showed that E. coli/IL-35 as a novel oral IL-35 delivery system alleviated inflammatory damage of colonic tissue in the colitic mice. Genetic therapeutic strategies using engineered E. coli encoding immunoregulatory cytokines may provide a potential approach for the treatment of IBD.

Allergic Rhinitis and Its Relationship with IL-10, IL-17, TGF-β, IFN-γ, IL 22, and IL-35

BACKGROUND

We aimed in our study to research the role of new cytokines such as IL-35, IL-22, and IL-17 that may form a target for novel treatment approaches.

METHODS

IL-10, IL-17, TGF-β, IFN-γ, IL-22, and IL-35 serum levels of allergic rhinitis (AR) patients were measured using ELISA method. Allergic sensitization was demonstrated by the skin prick test. Patients only with olive tree sensitivity were evaluated for seasonal AR (SAR). Patients only with mite sensitivity were included in the study for perennial AR (PAR). AR clinic severity was demonstrated by the nasal symptom scores (NSS).

RESULTS

In total, 65 AR patients (patient group), having 31 PAR and 34 SAR patients, and 31 healthy individuals (control group) participated in the study. Cytokine levels between the patient group and the control group were compared; IL-17 (p = 0.038), IL-22 (p = 0.001), and TGF-β (p = 0.031) were detected as high in the patient group, and IFN-γ (p < 0.001) was detected as low in the patient group. When correlation analysis was made between age, gender, prick test result, NSS, AR duration, and cytokine levels in the patient group, a negative correlation was detected only between IFN-γ (p = 0.032/r = -0.266) level and NSS.

CONCLUSIONS

Accompanied by the literature information, these results made us think that T cell subgroups and cytokines have an important role in AR immunopathogenesis. It is thought that future studies to be conducted relating to this subject will form new targets in treatment.

IL-35 induces N2 phenotype of neutrophils to promote tumor growth

IL-35 is an immunosuppressive cytokine and exerts regulatory effects on T cells, B cells, macrophages and dendritic cells. Neutrophils are important innate immune cells that play key roles in tumor development. The effect of IL-35 on neutrophils remains unknown. Here, we report that IL-35 can induce N2 neutrophil polarization (protumor phenotype) by increasing G-CSF and IL-6 production, and promote neutrophil infiltration into tumor microenvironment. The sustained expression of IL-35 could promote chronic inflammation to augment the proangiogenic and immunosuppressive function of neutrophils. IL-35 stimulated macrophages to secrete proinflammatory cytokines IL-1β and IL-6. IL-1β stimulated γδ T cells to produce IL-17, which in turn increased the production of G-CSF. By increasing the expression of G-CSF and IL-6, IL-35 could up-regulate the expression of MMP-9 and Bv8, and down-regulate TRAIL expression in neutrophils, thus augmenting the proangiogenic function of neutrophils. Moreover, G-CSF/IL-6 induced the enhanced activation of STAT3 and ERK pathways in neutrophils, thus increasing the expression of iNOS to suppress T cell activation. Our findings suggest that IL-35 can promote tumor progression by functioning as an up-stream cytokine to promote cancer-associated inflammation and control neutrophil polarization. Targeting IL-35 might be an important approach for designing new strategy of tumor therapy.

Mechanisms of Tolerance Induction by Dendritic Cells In Vivo

Dendritic cells (DCs) are a heterogeneous population playing a pivotal role in immune responses and tolerance. DCs promote immune tolerance by participating in the negative selection of autoreactive T cells in the thymus. Furthermore, to eliminate autoreactive T cells that have escaped thymic deletion, DCs also induce immune tolerance in the periphery through various mechanisms. Breakdown of these functions leads to autoimmune diseases. Moreover, DCs play a critical role in maintenance of homeostasis in body organs, especially the skin and intestine. In this review, we focus on recent developments in our understanding of the mechanisms of tolerance induction by DCs in the body.