Phenotypic and functional features of human Th17 cells

Sirtuins are crucial regulators of T cell metabolism and functions

It is well known that metabolism underlies T cell differentiation and functions. The pathways regulating T cell metabolism and function are interconnected, and changes in T cell metabolic activity directly impact the effector functions and fate of T cells. Thus, understanding how metabolic pathways influence immune responses and ultimately affect disease progression is paramount. Epigenetic and posttranslational modification mechanisms have been found to control immune responses and metabolic reprogramming. Sirtuins are NAD⁺-dependent histone deacetylases that play key roles during cellular responses to a variety of stresses and have recently been reported to have potential roles in immune responses. Therefore, sirtuins are of significant interest as therapeutic targets to treat immune-related diseases and enhance antitumor immunity. This review aims to illustrate the potential roles of sirtuins in different subtypes of T cells during the adaptive immune response.

Sirtuins, enzymes that regulate how cells respond to stress, regulate T cell metabolism and functions, and therefore blocking or boosting sirtuins influences immune responses. As part of the immune system, some types of T cells attack specific targets; others keep the immune response in check. Imene Hamaidi and Sungjune Kim at H. Lee Moffitt Cancer Center, Tampa, USA, have reviewed how sirtuins affect different subsets of T cells to either promote or suppress immune responses. Boosting sirtuins that increase the function of inflammation-suppressing T cells can improve outcomes for transplant recipients or help treat autoimmune diseases. Conversely, stimulating immune-activating sirtuins can help re-energize exhausted antitumor T cells. Understanding the complex web of sirtuin–T cell interactions may help in developing therapeutic strategies for improving transplant outcomes, and for treating autoimmune diseases and cancer.

Influenza Vaccine Associated with the Gene Expression of T Cell Surface Markers in Human Milk

Background: The function of neonatal T cells is reduced compared to adult T cells. T cells could be transferred to the infants through human milk and compensate for their immature T cells. As the subsets of T cells present in human milk have been incompletely described, this study investigated the association between the maternal factors (influenza vaccine, maternal age, and lactation time), the gene expression of T cell surface markers (cluster of differentiation [CD] and chemokine receptors [CCR]), and the concentrations of T cell-related cytokines in human milk. Materials and Methods: The gene expressions of T cell markers and the concentrations of T cell-related cytokines were determined in milk samples from 16 women. Eight donors received influenza vaccine, and eight were not vaccinated during 2019-2020 for the flu season 2020. Results: For T cell surface markers, the gene expression of CD8A was higher than CD4, CCR6, CD25, CXCR5, CD62L, and CD44 in human milk. CD44 copy gene was lower than CCR7 and CXCR3, while CD4 copy gene was lower than CXCR3 in human milk. Women with influenza vaccine had higher copy genes of CD44, CD8A, CD62L, and CD25 and lower CCR7 copy gene in milk than in women without influenza vaccine. Interleukin-17 concentration in human milk decreased with increasing lactation time. Gene expression of T cell markers and cytokine concentrations varied between lactating women. Conclusions: Although a larger study is needed, it appears that the influenza vaccine is associated with the gene expression of T cell markers in human milk.

The Role of T Lymphocytes in Cutaneous Scarring

Significance: Cutaneous scarring affects millions of patients worldwide and results in significant financial and psychosocial burdens. Given the immune system's intricate involvement in the initiation and progression of wound healing, it is no surprise that the scarring outcome can be affected by the actions of various immune cells and the cytokines and growth factors they produce. Understanding the role of T cells in regulating immune responses and directing the action of wound mesenchymal cells is essential to developing antifibrotic therapies to reduce the burden of scarring. Recent Advances: As the immune system is intimately involved in wound healing, much work has examined the impact of T cells and their cytokines on the final wound outcome. New innovative tools for studying T cells have resulted in more sophisticated immunophenotyping capabilities and the ability to examine effects of individual cytokines in the wound environment. Critical Issues: Despite continued advances in the study of specific immune cells and their effects on dermal fibrosis, minimal progress has been made to modulate immune responses to result in improved wound cosmesis. Future Directions: The actions of T cells represent potential pharmacologic targets that could lead to novel bioengineered or immunoengineered therapies to improve the lives of people with cutaneous scarring.

Th17 cells in the liver: balancing autoimmunity and pathogen defense

In addition to carcinogenesis, T helper 17 (Th17) cells (a subtype of CD4 + T lymphocytes) are involved in the acute, chronic, and cirrhotic phases of liver diseases; however, their role in the development and progression of liver diseases remains unclear. It is difficult to elucidate the role of Th17 cells in liver diseases due to their dichotomous nature, i.e., plasticity in terms of pathogenic or host protective function depending on environmental and time phase factors. Moreover, insufficient depletion of Th17 cells by inhibiting the cytokines and transcription factors involved in their production causes difficulties in analyzing their specific role in vitro and in vivo murine models, partially due to complex interaction. This review summarizes the recent progress in understanding the plasticity and function of hepatic Th17 cells and type 3 cytokines.

The Role of Interleukins in Recurrent Implantation Failure: A Comprehensive Review of the Literature

Recurrent implantation failure (RIF) is a multifactorial condition affecting 10-15% of in vitro fertilization (IVF) couples. Data suggest that functional dysregulation of the endometrial immune system constitutes one of the main pathophysiological mechanisms leading to RIF. The aim of this article is to provide a thorough presentation and evaluation of the role of interleukins (ILs) in the pathogenesis of RIF. A comprehensive literature screening was performed summarizing current evidence. During implantation, several classes of ILs are secreted by epithelial and stromal endometrial cells, including IL-6, IL-10, IL-12, IL-15, IL-18, and the leukemia inhibitory factor. These ILs create a perplexing network that orchestrates both proliferation and maturation of uterine natural killer cells, controls the function of regulatory T and B cells inhibiting the secretion of antifetal antibodies, and supports trophoblast invasion and decidua formation. The existing data indicate associations between ILs and RIF. The extensive analysis performed herein concludes that the dysregulation of the ILs network indeed jeopardizes implantation leading to RIF. This review further proposes a mapping of future research on how to move forward from mere associations to robust molecular data that will allow an accurate profiling of ILs in turn enabling evidence-based consultancy and decision making when addressing RIF patients.

The Molecular Mechanisms of Intestinal Inflammation and Fibrosis in Crohn’s Disease

Crohn’s disease (CD) is an inflammatory bowel disease (IBD) with repeated remissions and relapses. As the disease progresses, fibrosis and narrowing of the intestine occur, leading to severe complications such as intestinal obstruction. Endoscopic balloon dilatation, surgical stricture plasty, and bowel resection have been performed to treat intestinal stenosis. The clinical issue is that some patients with CD have a recurrence of intestinal stenosis even after the medical treatments. On the other hand, there exist no established medical therapies to prevent stenosis. With the progressive intestinal inflammation, cytokines and growth factors, including transforming growth factor (TGF-β), stimulate intestinal myofibroblasts, contributing to fibrosis of the intestine, smooth muscle hypertrophy, and mesenteric fat hypertrophy. Therefore, chronically sustained inflammation has long been considered a cause of intestinal fibrosis and stenosis. Still, even after the advent of biologics and tighter control of inflammation, intestinal fibrosis’s surgical rate has not necessarily decreased. It is essential to elucidate the mechanisms involved in intestinal fibrosis in CD from a molecular biological level to overcome clinical issues. Recently, much attention has been paid to several key molecules of intestinal fibrosis: peroxisome proliferator-activating receptor gamma (PPARγ), toll-like receptor 4 (TLR4), adherent-invasive Escherichia coli (AIEC), Th17 immune response, and plasminogen activator inhibitor 1 (PAI-1). As a major problem in the treatment of CD, the pathophysiology of patients with CD is not the same and varies depending on each patient. It is necessary to integrate these key molecules for a better understanding of the mechanism of intestinal inflammation and fibrosis.

Identification of Corosolic and Oleanolic Acids as Molecules Antagonizing the Human RORγT Nuclear Receptor Using the Calculated Fingerprints of the Molecular Similarity

RORγT is a protein product of the RORC gene belonging to the nuclear receptor subfamily of retinoic-acid-receptor-related orphan receptors (RORs). RORγT is preferentially expressed in Th17 lymphocytes and drives their differentiation from naive CD4+ cells and is involved in the regulation of the expression of numerous Th17-specific cytokines, such as IL-17. Because Th17 cells are implicated in the pathology of autoimmune diseases (e.g., psoriasis, inflammatory bowel disease, multiple sclerosis), RORγT, whose activity is regulated by ligands, has been recognized as a drug target in potential therapies against these diseases. The identification of such ligands is time-consuming and usually requires the screening of chemical libraries. Herein, using a Tanimoto similarity search, we found corosolic acid and other pentacyclic tritepenes in the library we previously screened as compounds highly similar to the RORγT inverse agonist ursolic acid. Furthermore, using gene reporter assays and Th17 lymphocytes, we distinguished compounds that exert stronger biological effects (ursolic, corosolic, and oleanolic acid) from those that are ineffective (asiatic and maslinic acids), providing evidence that such combinatorial methodology (in silico and experimental) might help wet screenings to achieve more accurate results, eliminating false negatives.

The role of diosgenin in crohn’s disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammation that can grossly affect the entire gastrointestinal tract (GIT) from the mouth to the anus. Crohn’s disease is the most known type of IBD and has been the focus of attention due to its increase in prevalence worldwide. Although the etiology is yet to be elucidated, recent studies have pointed out Crohn’s disease to arise from a complex interaction between environmental influences, genetic predisposition, and altered gut microbiota, resulting in dysregulated adaptive and innate responses. The presenting hallmarks of Crohn’s disease may include weight loss, nausea, vomiting, abdominal pain, diarrhea, fever, or chills. Treatment is usually done with many approved immunosuppressive drugs and surgery. However, a promising avenue from natural compounds is a safer therapy due to its safe natural active ingredients and the strong activity it shows in the treatment and management of diseases. Diosgenin, “a major biologically active natural steroidal sapogenin found in Chinese yam,” has been widely reported as a therapeutic agent in the treatment of various classes of disorders such as hyperlipidemia, inflammation, diabetes, cancer, infection, and immunoregulation. In this review, an analysis of literature data on diosgenin employed as a therapeutic agent for the treatment of Crohn’s disease is approached, to strengthen the scientific database and curtail the dreadful impact of Crohn’s disease.

The Tuberculous Granuloma and Preexisting Immunity

Pulmonary granulomas are widely considered the epicenters of the immune response to Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Recent animal studies have revealed factors that either promote or restrict TB immunity within granulomas. These models, however, typically ignore the impact of preexisting immunity on cellular organization and function, an important consideration because most TB probably occurs through reinfection of previously exposed individuals. Human postmortem research from the pre-antibiotic era showed that infections in Mtb-naïve individuals (primary TB) versus those with prior Mtb exposure (postprimary TB) have distinct pathologic features. We review recent animal findings in TB granuloma biology, which largely reflect primary TB. We also discuss our current understanding of postprimary TB lesions, about which much less is known. Many knowledge gaps remain, particularly regarding how preexisting immunity shapes granuloma structure and local immune responses at Mtb infection sites.

Expected final online publication date for the Annual Review of Immunology, Volume 40 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Th17 CD4+ T-Cell as a Preferential Target for HIV Reservoirs

Among CD4+ T-cells, T helper 17 (Th17) cells play a sentinel role in the defense against bacterial/fungal pathogens at mucosal barriers. However, Th17 cells are also highly susceptible to HIV-1 infection and are rapidly depleted from gut mucosal sites, causing an imbalance of the Th17/Treg ratio and impairing cytokines production. Consequently, damage to the gut mucosal barrier leads to an enhanced microbial translocation and systemic inflammation, a hallmark of HIV-1 disease progression. Th17 cells’ expression of mucosal homing receptors (CCR6 and α4β7), as well as HIV receptors and co-receptors (CD4, α4β7, CCR5, and CXCR4), contributes to susceptibility to HIV infection. The up-regulation of numerous intracellular factors facilitating HIV production, alongside the downregulation of factors inhibiting HIV, helps to explain the frequency of HIV DNA within Th17 cells. Th17 cells harbor long-lived viral reservoirs in people living with HIV (PLWH) receiving antiretroviral therapy (ART). Moreover, cell longevity and the proliferation of a fraction of Th17 CD4 T cells allow HIV reservoirs to be maintained in ART patients.

Contributions of Immune Cells and Stromal Cells to the Pathogenesis of Systemic Sclerosis: Recent Insights

Systemic sclerosis (SSc) is a multisystem rheumatic disease characterized by vascular dysfunction, autoimmune abnormalities, and progressive organ fibrosis. A series of studies in SSc patients and fibrotic models suggest that immune cells, fibroblasts, and endothelial cells participate in inflammation and aberrant tissue repair. Furthermore, the growing number of studies on single-cell RNA sequencing (scRNA-seq) technology in SSc elaborate on the transcriptomics and heterogeneities of these cell subsets significantly. In this review, we summarize the current knowledge regarding immune cells and stromal cells in SSc patients and discuss their potential roles in SSc pathogenesis, focusing on recent advances in the new subtypes by scRNA-seq.

The Molecular Mechanisms Through Which Placental Mesenchymal Stem Cell-Derived Extracellular Vesicles Promote Myelin Regeneration

Multiple sclerosis (MS) is a debilitating degenerative disease characterized by an immunological attack on the myelin sheath leading to demyelination and axon degeneration. Mesenchymal stem/stromal cells (MSCs) and secreted extracellular vesicles (EVs) have become attractive targets as therapies to treat neurodegenerative diseases such as MS due to their potent immunomodulatory and regenerative properties. The placenta is a unique source of MSCs (PMSCs), demonstrates "fetomaternal" tolerance during pregnancy, and serves as a novel source of MSCs for the treatment of neurodegenerative diseases. PMSCs and PMSC-EVs have been shown to promote remyelination in animal models of MS, however, the molecular mechanisms by which modulation of autoimmunity and promotion of myelination occurs have not been well elucidated. The current review will address the molecular mechanisms by which PMSC-EVs can promote remyelination in MS.

Role of rare immune cells in common variable immunodeficiency

Common variable immunodeficiency disorder (CVID) is a heterogeneous disorder and the most common symptomatic antibody deficiency disease characterized with hypogammaglobulinemia and a broad range of clinical manifestations. Multiple genetic, epigenetic, and immunological defects are involved in the pathogenesis of CVID. These immunological defects include abnormalities in the number and/or function of B lymphocytes, T lymphocytes, and other rare immune cells. Although some immune cells have a relatively lower proportion among total immune subsets in the human body, they could have important roles in the pathogenesis of immunological disorders like CVID. To the best of our knowledge, this is the first review that described the role of rare immune cells in the pathogenesis and clinical presentations of CVID.

Immunometabolism in biofilm infection: lessons from cancer

BACKGROUND

Biofilm is a community of bacteria embedded in an extracellular matrix, which can colonize different human cells and tissues and subvert the host immune reactions by preventing immune detection and polarizing the immune reactions towards an anti-inflammatory state, promoting the persistence of biofilm-embedded bacteria in the host.

MAIN BODY OF THE MANUSCRIPT

It is now well established that the function of immune cells is ultimately mediated by cellular metabolism. The immune cells are stimulated to regulate their immune functions upon sensing danger signals. Recent studies have determined that immune cells often display distinct metabolic alterations that impair their immune responses when triggered. Such metabolic reprogramming and its physiological implications are well established in cancer situations. In bacterial infections, immuno-metabolic evaluations have primarily focused on macrophages and neutrophils in the planktonic growth mode.

CONCLUSION

Based on differences in inflammatory reactions of macrophages and neutrophils in planktonic- versus biofilm-associated bacterial infections, studies must also consider the metabolic functions of immune cells against biofilm infections. The profound characterization of the metabolic and immune cell reactions could offer exciting novel targets for antibiofilm therapy.

Immune mechanisms in oral lichen planus

Oral lichen planus (OLP) is a T-cell-mediated inflammatory disease of the oral mucosa that has been extensively researched over many years but as yet the mechanisms of pathogenesis are still not fully understood. Whilst the specific etiologic factors driving OLP remain ambiguous, evidence points to the development of a chronic, dysregulated immune response to OLP-mediating antigens presented by innate immune cells and oral keratinocytes leading to increased cytokine, chemokine and adhesion molecule expression. These molecules recruit T-cells and mast cells to the diseased site and orchestrate a complex interplay between cells that culminates in keratinocyte cell death, mucosal basement membrane destruction and long-term chronicity of the disease. The main lymphocytes involved are thought to be CD8+ cytotoxic and CD4+ Th1 polarised T-cells although recent evidence indicates the involvement of other Th subsets such as Th9, Th17 and Tregs, suggesting that a more complex immune cell relationship exists during the disease process. This review provides an overview of the immune mechanisms at play in OLP pathogenesis with particular emphasis on the role of the different Th subsets and how these recent discoveries may guide research toward identifying potential therapeutic targets.

Involvement of Th1Th17 Cell Subpopulations in the Immune Responses of Mothers Who Gave Birth to Children with Congenital Zika Syndrome (CZS)

High levels of T helper 17 cell (Th17)-related cytokines have been shown in acute Zika virus (ZIKV) infection. We hypothesized that the high levels of Th17-related cytokines, associated with a regulatory environment during pregnancy, create a favorable milieu for the differentiation of CD4+Th17 cells. We present data from a cross-sectional study on mothers who confirmed ZIKV infection by qRT-PCR and their children. We also recruited non-pregnant women infected with ZIKV in the same period. ZIKV infection occurred between 2015 and 2017. We collected samples for this study between 2018 and 2019, years after the initial infection. We highlight that, after in vitro stimulation with ZIKV CD4 megapool (ZIKV MP), we found a lower frequency of IL-17-producing CD4+ T cells (Th17), especially in the mothers, confirmed by the decrease in IL-17 production in the supernatant. However, a higher frequency of CD4+ IL-17+ IFN-γ+ T cells (Th1Th17) responding to the ZIKV MP was observed in the cells of the mothers and children but not in those of the non-pregnant women. Our data indicate that the priming of CD4 T cells of the Th1Th17 phenotype occurred preferentially in the mothers who gave birth to children with CZS and in the children.

[Biologics in inflammatory bowel diseases]

BACKGROUND

In addition to conventional anti-inflammatory treatment for chronic inflammatory bowel disease (IBD), there has been an evolution of new treatment options over the past 20 years. Already approved biologics provide multiple treatment alternatives but also make the treatment algorithms more complex. This development results in a substantial improvement in patient care. The ambitious treatment targets are associated with a higher quality of life and the reduction of long-term disability and morbidity.

OBJECTIVE

The aim of this article is to give an overview of how biologics can currently be implemented in IBD. In particular, the current clinical management is presented and an outlook on future treatment options with biologics for IBD is provided.

MATERIAL AND METHODS

A search was carried out in PubMed and ClinicalTrials.gov and the current German and European guidelines and expert recommendations were evaluated.

RESULTS

Since the late 1990s there have been a continuously increasing number of treatment options for IBD. All substances have proven safety and efficacy in large randomized clinical studies and enable increasingly more individualized treatment for patients with IBD. Biologics are currently the standard treatment of choice for moderate to severe inflammatory activity as well as for steroid-refractory or steroid-dependent courses of disease after failure of conventional treatment.

CONCLUSION

The diversity of IBD treatment offers increasing treatment options and thus improved patient care; however, as the number of new substances increases treatment becomes more complex. This article summarizes the current and future treatment options for IBD and their integration into current treatment algorithms.

Disturbed expression of vitamin D and retinoic acid-related orphan receptors α and γ and of megalin in inflammatory skin diseases

The pathogenesis of inflammatory skin diseases is associated with the abnormal activity of keratinocytes and immune cells infiltrate. Vitamin D₃ deficiency can correlate with the increased incidence, severity and duration of inflammatory skin disorders. The exact mechanism on how vitamin D₃ influences inflammatory skin diseases still requires clarification. However, it can be associated with the disturbances in transmembrane glycoprotein-LRP2/megalin, which is implicated in vitamin D₃ transport to the cell, and defects in vitamin D-signalling through the nuclear receptors. Therefore, by using immunohistochemistry, we analysed the expression of LRP2/megalin, VDR, RORα and RORγ in allergic contact dermatitis, lichen simplex chronicus, sarcoidosis and psoriasis in comparison with the normal skin. We observed decreased expression of LRP2/megalin in all inflammatory lesions in comparison with the normal skin. Significant differences were also noticed in VDR, RORα and RORγ levels between inflammatory lesions and normal skin. Our research indicates disturbed expression of LRP2/megalin, VDR, RORα and RORγ in inflammatory skin lesions in comparison with normal skin. Therefore, we suggest that changes in the activity of these proteins may play role in pathogenesis of inflammatory skin disorders. Furthermore, we suggest that LRP2/megalin, VDR, RORα and RORy may serve as targets in therapy of these diseases.

Flow Cytometry Sorting of Memory CCR6+CD4+ T-Cells for HIV Reservoir Quantification

Antiretroviral therapy (ART) has transformed the deadly human immunodeficiency virus type I (HIV-1) epidemic into a manageable chronic condition. Current ART is not curative and treatment interruption leads to viral rebound in people living with HIV-1 (PLWH). The main cause of viral rebound is the persistence of HIV reservoirs in long-lived memory CD4⁺ T cells. Accurate techniques to identify and quantify viral reservoirs are required to monitor therapeutic approaches designed to cure HIV infection. Th17-polarized CD4⁺ T cells are located at mucosal sites of HIV entry and are preferentially targeted for infection and viral reservoir persistence. They constitute an important reservoir in both blood and colon. In this chapter we describe a step-by-step flow cytometry-based protocol to isolate a fraction of Th17-enriched cells from PBMC based on their expression of the Th17 surface marker CCR6. The isolation of memory CCR6⁺CD4⁺ T cells allows subsequent PCR/RT-PCR-based HIV DNA/RNA quantifications, as well as their culture for quantitative viral outgrowth assays (QVOA). This method can be adapted for the isolation of CCR6⁺CD4⁺ T cells from peripheral tissues, such as the colon.

T cell transgressions: Tales of T cell form and function in diverse disease states

Insights into T cell form, function, and dysfunction are rapidly evolving. T cells have remarkably varied effector functions including protecting the host from infection, activating cells of the innate immune system, releasing cytokines and chemokines, and heavily contributing to immunological memory. Under healthy conditions, T cells orchestrate a finely tuned attack on invading pathogens while minimizing damage to the host. The dark side of T cells is that they also exhibit autoreactivity and inflict harm to host cells, creating autoimmunity. The mechanisms of T cell autoreactivity are complex and dynamic. Emerging research is elucidating the mechanisms leading T cells to become autoreactive and how such responses cause or contribute to diverse disease states, both peripherally and within the central nervous system. This review provides foundational information on T cell development, differentiation, and functions. Key T cell subtypes, cytokines that create their effector roles, and sex differences are highlighted. Pathological T cell contributions to diverse peripheral and central disease states, arising from errors in reactivity, are highlighted, with a focus on multiple sclerosis, rheumatoid arthritis, osteoarthritis, neuropathic pain, and type 1 diabetes.

Melatonin attenuates cerebral hypoperfusion-induced hippocampal damage and memory deficits in rats by suppressing TRPM7 channels

This study was conducted to examine if modulating transporters like transient receptor potential cation channels, subfamily M, member 7 (TRPM7) underlies the hippocampal neuroprotection afforded by melatonin (Mel) in rats exposed to cerebral hypoperfusion (CHP). Experimental groups included control, Mel-treated (1.87 g/kg), CHP, and CHP + Mel (1.87 g/kg)-treated rats. CHP was induced by the permanent bilateral occlusion of the common carotid arteries (2VO) method and treatments were conducted for 7 days, orally. Mel prevented the damage of the dental gyrus and memory loss in CHP rats and inhibited the hippocampal reactive oxygen species (ROS), lipid peroxidation levels of tumor necrosis factor-α (TNF-α), interleukine-6 (IL-6), interleukine-1 beta (IL-1β), and prostaglandin E2 (PGE2). It also reduced the hippocampal transcription of the TRPM7 channels and lowered levels of calcium (Ca²⁺) and zinc (Zn²⁺). Mel Also enhanced the levels of total glutathione (GSH) and superoxide dismutase (SOD) in the hippocampus of the control and CHP-treated rats. In conclusion, downregulation of TRPM7 seems to be one mechanism underlying the neuroprotective effect of Mel against global ischemia and is triggered by its antioxidant potential.

Treatment With Cladribine Selects IFNγ+IL17+ T Cells in RRMS Patients - An In Vitro Study

Background

Multiple sclerosis (MS) is an incurable autoimmune disease mediated by a heterogeneous T cell population (CD3+CD161+CXCR3−CCR6+IFNγ−IL17+, CD3+CXCR3+CCR6+IFNγ+IL17+, and CD3+CXCR3+IFNγ+IL17− phenotypes) that infiltrates the central nervous system, eliciting local inflammation, demyelination and neurodegeneration. Cladribine is a lymphocyte-depleting deoxyadenosine analogue recently introduced for MS therapy as a Disease Modifying Drug (DMD). Our aim was to establish a method for the early identification and prediction of cladribine responsiveness among MS patients.

Methods

An experimental model was designed to study the cytotoxic and immunomodulatory effect of cladribine. T cell subsets of naïve relapsing-remitting MS (RRMS) patients were analyzed ex vivo and in vitro comparatively to healthy controls (HC). Surviving cells were stimulated with rh-interleukin-2 for up to 14days. Cell proliferation and immunophenotype changes were analyzed after maximal (phorbol myristate acetate/ionomycin/monensin) and physiological T-cell receptor (CD3/CD28) activation, using multiparametric flow cytometry and xMAP technology.

Results

Ex vivo CD161+Th17 cells were increased in RRMS patients. Ex vivo to in vitro phenotype shifts included: decreased CD3+CCR6+ and CD3+CD161+ in all subjects and increased CD3+CXCR3+ in RRMS patients only; Th17.1 showed increased proliferation vs Th17 in all subjects; CD3+IL17+ and CD3+IFNγ+IL17+ continued to proliferate till day 14, CD3+IFNγ+ only till day 7. Regarding cladribine exposure: RRMS CD3+ cells were more resistant compared to HC; treated CD3+ cells proliferated continuously for up to 14 days, while untreated cells only up to 7 days; both HC/RRMS CD3+CXCR3+ populations increased from baseline till day 14; in RRMS patients vs HC, IL17 secretion from cladribine-treated cells increased significantly, in line with the observed proliferation of CD3+IL17+ and CD3+IFNγ+IL17+ cells; in both HC/RRMS, cladribine led to a significant increase in CD3+IFNγ+ cells at day 7 only, having no further effect at day14. IFNγ and IL17 secreted in culture media decreased significantly from ex vivo to in vitro.

Conclusions

CD3+ subtypes showed different responsiveness due to selectivity of cladribine action, in most patients leading to in vitro survival/proliferation of lymphocyte subsets known as pathogenic in MS. This in vitro experimental model is a promising tool for the prediction of individual responsiveness of MS patients to cladribine and other DMDs.

The Pathogenic Roles of IL-22 in Colitis: Its Transcription Regulation by Musculin in T Helper Subsets and Innate Lymphoid Cells

IL-22 plays a crucial role in promoting inflammation, antimicrobial immunity and tissue repair at barrier surfaces. The role of IL-22 in colitis is still controversial: while IL-22 has a protective effect on gut epithelium in acute injuries, it also enhances colitis in a context-dependent manner. Here, we summarize the Yin and Yang of IL-22 in colitis. Particularly, we emphasize the role of innate lymphoid cells (ILCs) in IL-22 production and regulation. A previously underappreciated transcription factor, Musculin (MSC), has been recently identified to be expressed in not only Th17 cells, but also RORγt+/Id2+ IL-22-producing group 3 ILCs in the gut of naïve mice. We hypothesize that the co-expression and interaction of MSC with the key transcription repressor Id2 in developing lymphoid cells (e.g., in LTi cells) and ILC precursors might fine tune the developmental programs or regulate the plasticity of adaptive Th subset and innate ILCs. The much-elevated expression of IL-22 in MSC-/- ILC3s suggests that MSC may function as: 1) a transcription suppressor for cytokines, particularly for IL-22, and/or 2) a gatekeeper for specific lineages of Th cells and innate ILCs as well. Amelioration of colitis symptoms in MSC-/- mice by IL-22-blocking agent IL-22BP-Fc suggests a counterintuitive pathogenic role of IL-22 in the absence of MSC as a checkpoint. The theory that exuberant production of IL-22 under pathological conditions (e.g., in human inflammatory bowel disease, IBD) may cause epithelial inflammation due to endoplasmic reticulum (ER) stress response is worth further investigation. Rheostatic regulation of IL-22 may be of therapeutic value to restore homeostatic balance and promote intestinal health in human colitis.

Immune Cell Plasticity Allows for Resetting of Phenotype From Effector to Regulator With Combined Inhibition of Notch/eIF5A Pathways

Type 1 diabetes (T1D) results from the destruction of pancreatic β-cells caused by an altered immune balance in the pancreatic microenvironment. In humans as well as in mouse models, T cells are well recognized as key orchestrators of T1D, which is characterized by T helper (Th) 1 and Th17 cell bias and/or low/defective T-regulatory cells (Treg), and culminates in cytotoxic T-cell (CTL)-mediated destruction of β-cells. Refitting of immune cells toward the non-inflammatory phenotype in the pancreas may represent a way to prevent/treat T1D. Recently we developed a unique spontaneous humanized mouse model of type 1 diabetes, wherein mouse MHC-II molecules were replaced by human DQ8, and β-cells were made to express human glutamic acid decarboxylase (GAD) 65 auto-antigen. The mice spontaneously developed T1D resembling the human disease. Humanized T1D mice showed hyperglycemic (250-300 mg/dl) symptoms by the 4th week of life. The diabetogenic T cells (CD4, CD8) present in our model are GAD65 antigen-specific in nature. Intermolecular antigen spreading recorded during 3rd-6th week of age is like that observed in the human preclinical period of T1D. In this paper, we tested our hypothesis in our spontaneous humanized T1D mouse model. We targeted two cell-signaling pathways and their inhibitions: eIF5A pathway inhibition influences T helper cell dynamics toward the non-inflammatory phenotype and Notch signaling inhibition enrich Tregs and targets auto-reactive CTLs, rescues the pancreatic islet structure, and increases the functionality of β-cells in terms of insulin production. We report that inhibition of (eIF5A + Notch) signaling mediates suppression of diabetogenic T cells by inducing plasticity in CD4 + T cells co-expressing IL-17 and IFNγ (IL-17 + IFNγ +) toward the Treg cells phenotype.

Cellular heterogeneity of circulating CD4+CD8+ double-positive T cells characterized by single-cell RNA sequencing

Circulating CD4⁺CD8⁺ double-positive (DP) T cells are associated with a variety of disease states. However, unlike conventional T cells, the composition of this population is poorly understood. Here, we used single-cell RNA sequencing (scRNA-seq) to analyze the composition and characteristics of the DP T cell population circulating in the peripheral blood of cynomolgus monkeys. We found that circulating DP T cells not only contain a large number of naïve cells, but also comprise a heterogeneous population (CD4 CTL-, Eomes⁺ Tr1-, Th2-, Th17-, Tfh-, Treg-, CD8 CTL-, and innate-like cells) with multiple potential functions. Flow cytometry analysis revealed that a substantial number of the naïve DP T cells expressed CD8αβ, as well as CD8αα, along with high expression of CD31. Moreover, the CD4^hiCD8^lo and CD4^hiCD8^hi populations, which express high levels of the CD4 coreceptor, comprised subsets characterized by helper and regulatory functions, some of which also exhibited cytotoxic functions. By contrast, the CD4^loCD8^hi population with high CD8 coreceptor expression comprised a subset characterized by CD8 CTL- and innate-like properties. Taken together, the data show that scRNA-seq analysis identified a more diverse subset of the circulating DP cells than is currently known, despite this population being very small.

Influence of Vitamin D3 Levels and T Cell-Related Cytokines in Human Milk on Coronavirus Disease 2019 Infection in Lactating Women

Background: Vitamin D deficiency was associated with an increased risk of coronavirus disease 2019 (COVID-19) infection. Vitamin D deficient mothers are more likely to have infants with vitamin D deficiency, affecting their immunity and protection against infection. This study aimed at comparing the concentrations of vitamin D3 and T cell-related cytokines in milk between mothers with confirmed COVID-19 polymerase chain reaction (PCR) test, mothers with viral infections suggestive of COVID-19, and mothers without infection. Materials and Methods: Concentrations of vitamin D3 and T cell-related cytokines in milk samples were determined by ELISA from 10 mothers who had a positive COVID-19 PCR test, 10 mothers with viral symptoms suggestive of COVID-19, and 20 mothers without infection. Results: Vitamin D3 concentration in human milk was higher in women without infection than in women with viral symptoms or COVID-19 PCR. Interleukin-2 level in milk was higher in the no-infection group than the COVID-19 PCR group but it did not differ with the viral symptoms group. Vitamin D3 did not correlate with any cytokines in human milk. Prenatal vitamin intake did not affect the vitamin D3 in human milk. The percentage of milk from mothers with <20 ng/mL of vitamin D3 was 50% in the COVID-19 PCR group, 60% in the viral symptoms group, and 5% in the no-infection group. Conclusions: Vitamin D3 level in breast milk may influence maternal immunity against COVID-19 infection. A larger study is needed to evaluate the relationship between vitamin D3 concentration in breast milk, maternal immune response, and the incidence of COVID-19 infection in lactating mothers.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer-reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state-of-the-art handbook for basic and clinical researchers.

IL-17A and IFN-γ are Up-regulated in CD4 and γδ T Cells in Active Behcet's Disease Patients

Involvement of γδ T cells is implicated in the pathogenesis of Behçet's disease (BD) as a bridge between innate and adaptive responses. IL-17 and IL-22 have also been shown to participate in the BD pathogenesis in addition to IFN-γ. Mainly CD4⁺ T cells are investigated previously for the production of these inflammatory cytokines. In this study, the role of γδ T cells in cytokine-related mechanisms was evaluated in BD in comparison to CD4⁺ T cells. Surface expression of markers for functional states of both CD4⁺ and γδ T cells were compared in ex vivo samples collected from patients with BD and healthy controls (HC). Sixteen active BD (a-BD), 9 inactive BD (i-BD) patients and 25 HC were investigated. The expression of CD161, CCR6 as markers for IL-17 producing cells were analyzed on γδ and CD4⁺ T cells. IFN-γ, IL-17A, IL-22, as well as CD107a (LAMP1) and CD16 (FcγRIII) were evaluated in both cell subtypes after in vitro stimulation. Only IFN-γ production was increased in γδ T cells of a-BD patients. There was no difference in increase of CD107a or decrease of CD16 surface expression on γδ T cells upon stimulation between the groups. Ex vivo IL-17A and both IL-17A/IFN-γ production and expression of CD161, CCR6 by CD4⁺ T cells were increased in a-BD. Along with CD4⁺ T cells, γδ T cells have complementary roles in cytokine production in BD. Higher IFN-γ production of γδ T cells suggests the role of an environmental triggers in BD pathogenesis, whereas IL-17 related activity is mainly provided by CD4⁺ T cells.

Integrative analysis of long non-coding RNA and messenger RNA expression in toll-like receptor 4-primed mesenchymal stem cells of ankylosing spondylitis

Background

The precise pathogenesis of ankylosing spondylitis (AS) is still largely unknown at present. Our previous study found that toll-like receptor 4 (TLR4) downregulated and performed immunoregulatory dysfunction in mesenchymal stem cells from AS patients (AS-MSCs). The aim of this study was to explore the expression profiles of long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in TLR4-primed AS-MSCs, and to clarify the potential mechanisms.

Methods

The immunoregulatory effects of MSCs were determined after TLR4 activation. Next, the differentially-expressed (DE) lncRNAs and mRNAs between AS-MSCs and TLR4-primed AS-MSCs [stimulated by lipopolysaccharide (LPS)] were identified via high-throughput sequencing followed by quantitative real-time PCR (qRT-PCR) confirmation. Finally, bioinformatics analyses were performed to identify the critical biological functions, signaling pathways, and associated functional networks involved in the TLR4-primed immunoregulatory function of AS-MSCs.

Results

A total of 147 DE lncRNAs and 698 DE mRNAs were identified between TLR4-primed AS-MSCs and unstimulated AS-MSCs. Of these, 107 lncRNAs were upregulated and 40 were downregulated (fold change ≥2, P<0.05), while 504 mRNAs were upregulated and 194 were downregulated (fold change ≥2, P<0.05). Five lncRNAs and five mRNAs with the largest fold changes were respectively verified by qRT-PCR. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses demonstrated that the DE mRNAs and lncRNAs were highly associated with the inflammatory response, such as NOD-like receptor (NLR) signaling pathway, the TNF signaling pathway and the NF-κB signaling pathway. Cis-regulation prediction revealed eight novel lncRNAs, while trans-regulation prediction revealed 15 lncRNAs, respectively. Eight core pairs of lncRNA and target mRNA in the lncRNA-transcription factor (TF)-mRNA network were as follows: PACERR-PTGS2, LOC105378085-SOD2, LOC107986655-HIVEP2, MICB-DT-MICB, LOC105373925-SP140L, LOC107984251-IFIT5, LOC112268267-GBP2, and LOC101926887-IFIT3, respectively.

Conclusions

TLR4 activation in AS can enhance the immunoregulatory ability of MSCs. Eight core pairs of lncRNA and target mRNA were observed in TLR4-primed AS-MSCs, which could contribute to understanding the potential mechanism of AS-MSC immunoregulatory dysfunction.

Crosstalk of Microorganisms and Immune Responses in Autoimmune Neuroinflammation: A Focus on Regulatory T Cells

Regulatory T cells (Tregs) are the major determinant of peripheral immune tolerance. Many Treg subsets have been described, however thymus-derived and peripherally induced Tregs remain the most important subpopulations. In multiple sclerosis, a prototypical autoimmune disorder of the central nervous system, Treg dysfunction is a pathogenic hallmark. In contrast, induction of Treg proliferation and enhancement of their function are central immune evasion mechanisms of infectious pathogens. In accordance, Treg expansion is compartmentalized to tissues with high viral replication and prolonged in chronic infections. In friend retrovirus infection, Treg expansion is mainly based on excessive interleukin-2 production by infected effector T cells. Moreover, pathogens seem also to enhance Treg functions as shown in human immunodeficiency virus infection, where Tregs express higher levels of effector molecules such as cytotoxic T-lymphocyte-associated protein 4, CD39 and cAMP and show increased suppressive capacity. Thus, insights into the molecular mechanisms by which intracellular pathogens alter Treg functions might aid to find new therapeutic approaches to target central nervous system autoimmunity. In this review, we summarize the current knowledge of the role of pathogens for Treg function in the context of autoimmune neuroinflammation. We discuss the mechanistic implications for future therapies and provide an outlook for new research directions.

Immunosuppression characterized by increased Treg cell and IL-10 levels in benzene-induced hematopoietic toxicity mouse model

Benzene is a typical hematopoietic toxic substance, that can cause serious blood and circulatory system diseases such as aplastic anemia, myelodysplastic syndrome and acute myeloid leukemia, but the immunological mechanism by which this occurs is not clear. T helper cells play a key role in regulating the immune balance in the body. In this study, benzene-induced hematopoietic toxicity BALB/c mice model was established, and changes in immune organs and T helper cell subsets (Th1, Th2, Th17 and Treg cells) were explored. At 28 days after subcutaneous injection of 150 mg/kg benzene, mice showed pancytopenia and obvious pathological damage to the bone marrow, spleen, and thymus. Flow cytometry revealed that the number of CD4⁺CD25⁺Foxp3⁺ Treg cells in the spleen increased significantly. The level of IL-10 in the spleen, serum, and bone marrow increased, while the levels of IL-17 in the spleen and serum decreased. Furthermore, the levels of CD4 and CD8 proteins in the spleen decreased. Immunofluorescence results showed that levels of Foxp3, a specific transcription factor that induced the differentiation of Treg cells, increased after exposure to benzene. Our results demonstrate that immunosuppression occurred in the benzene-induced hematopoietic toxicity model mice, and Treg cells and secreted IL-10 may play a key role in the process.

IL-17+ Mast Cell/T Helper Cell Axis in the Early Stages of Acne

Acne is a multifactorial disease driven by physiological changes occurring during puberty in the pilosebaceous unit (PSU) that leads to sebum overproduction and a dysbiosis involving notably Cutibacterium acnes. These changes in the PSU microenvironment lead to a shift from a homeostatic to an inflammatory state. Indeed, immunohistochemical analyses have revealed that inflammation and lymphocyte infiltration can be detected even in the infraclinical acneic stages, highlighting the importance of the early stages of the disease. In this study, we utilized a robust multi-pronged approach that included flow cytometry, confocal microscopy, and bioinformatics to comprehensively characterize the evolution of the infiltrating and resident immune cell populations in acneic lesions, beginning in the early stages of their development. Using a discovery cohort of 15 patients, we demonstrated that the composition of immune cell infiltrate is highly dynamic in nature, with the relative abundance of different cell types changing significantly as a function of clinical lesion stage. Within the stages examined, we identified a large population of CD69⁺ CD4⁺ T cells, several populations of activated antigen presenting cells, and activated mast cells producing IL-17. IL-17⁺ mast cells were preferentially located in CD4⁺ T cell rich areas and we showed that activated CD4⁺ T cells license mast cells to produce IL-17. Our study reveals that mast cells are the main IL-17 producers in the early stage of acne, underlying the importance of targeting the IL-17⁺ mast cell/T helper cell axis in therapeutic approaches.

Interactome Networks of FOSL1 and FOSL2 in Human Th17 Cells

Dysregulated function of Th17 cells has implications in immunodeficiencies and autoimmune disorders. Th17 cell differentiation is orchestrated by a complex network of transcription factors, including several members of the activator protein (AP-1) family. Among the latter, FOSL1 and FOSL2 modulate the effector functions of Th17 cells. However, the molecular mechanisms underlying these effects are unclear, owing to the poorly characterized protein interaction networks of FOSL factors. Here, we establish the first interactomes of FOSL1 and FOSL2 in human Th17 cells, using affinity purification-mass spectrometry analysis. In addition to the known JUN proteins, we identified several novel binding partners of FOSL1 and FOSL2. Gene ontology analysis found a significant fraction of these interactors to be associated with RNA-binding activity, which suggests new mechanistic links. Intriguingly, 29 proteins were found to share interactions with FOSL1 and FOSL2, and these included key regulators of Th17 fate. We further validated the binding partners identified in this study by using parallel reaction monitoring targeted mass spectrometry and other methods. Our study provides key insights into the interaction-based signaling mechanisms of FOSL proteins that potentially govern Th17 cell differentiation and associated pathologies.

Bacterial Translocation as Inflammatory Driver in Crohn's Disease

Crohn’s disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract responsible for intestinal lesions. The multifactorial etiology attributed to CD includes a combination of environmental and host susceptibility factors, which result in an impaired host–microbe gut interaction. Bacterial overgrowth and dysbiosis, increased intestinal barrier permeability, and altered inflammatory responses in patients with CD have been described in the past. Those events explain the pathogenesis of luminal translocation of bacteria or its products into the blood, a frequent event in CD, which, in turn, favors a sustained inflammatory response in these patients. In this review, we navigate through the interaction between bacterial antigen translocation, permeability of the intestinal barrier, immunologic response of the host, and genetic predisposition as a combined effect on the inflammatory response observed in CD. Several lines of evidence support that translocation of bacterial products leads to uncontrolled inflammation in CD patients, and as a matter of fact, the presence of gut bacterial genomic fragments at a systemic level constitutes a marker for increased risk of relapse among CD patients. Also, the significant percentage of CD patients who lose response to biologic therapies may be influenced by the translocation of bacterial products, which are well-known drivers of proinflammatory cytokine production by host immune cells. Further mechanistic studies evaluating cellular and humoral immune responses, gut microbiota alterations, and genetic predisposition will help clinicians to better control and personalize the management of CD patients in the future.

Th17 Cells in Periodontitis and Its Regulation by A20

Periodontitis is a prevalent chronic disease that results in loss of periodontal ligament and bone resorption. Triggered by pathogens and prolonged inflammation, periodontitis is modulated by the immune system, especially pro-inflammatory cells, such as T helper (Th) 17 cells. Originated from CD4⁺ Th cells, Th17 cells play a central role for they drive and regulate periodontal inflammation. Cytokines secreted by Th17 cells are also major players in the pathogenesis of periodontitis. Given the importance of Th17 cells, modulators of Th17 cells are of great clinical potential and worth of discussion. This review aims to provide an overview of the current understanding of the effect of Th17 cells on periodontitis, as well as a brief discussion of current and potential therapies targeting Th17 cells. Lastly, we highlight this article by summarizing the causal relationship between A20 (encoded by TNFAIP3), an anti-inflammatory molecule, and Th17 cell differentiation.

Regulatory T cells enhance Th17 migration in psoriatic arthritis which is reversed by anti-TNF

Regulatory T cells (Treg) prevent the migration of effector T cells toward sites of inflammation, thereby limiting disease progression. We investigated this aspect of Treg function using psoriatic arthritis (PsA) as an exemplar of chronic inflammation. Patients with PsA had an increased Th17:Treg ratio which was reversed by anti-tumor necrosis factor (TNF) therapy. Utilizing an in vitro migration assay, Treg from patients with PsA treated with conventional therapy paradoxically boosted CCR6⁺ effector T-cell (a surrogate for Th17) migration toward CCL20. In contrast, Treg from patients with PsA treated with anti-TNF suppressed CCL20-driven effector T-cell migration. The boosting effect of TNF blockade upon Treg suppression of migration was accompanied by increased effector T-cell CCL20 production and enhanced interaction between Treg and effector T cells. This study provides mechanistic insight into Treg modulation of effector T-cell migration in patients with chronic inflammation and how this can be targeted by therapy.

Th1 polarization defines the synovial fluid T cell compartment in oligoarticular juvenile idiopathic arthritis

Oligoarticular juvenile idiopathic arthritis (oligo JIA) is the most common form of chronic inflammatory arthritis in children, yet the cause of this disease remains unknown. To understand immune responses in oligo JIA, we immunophenotyped synovial fluid T cells with flow cytometry, bulk RNA-Seq, single-cell RNA-Seq (scRNA-Seq), DNA methylation studies, and Treg suppression assays. In synovial fluid, CD4+, CD8+, and γδ T cells expressed Th1-related markers, whereas Th17 cells were not enriched. Th1 skewing was prominent in CD4+ T cells, including Tregs, and was associated with severe disease. Transcriptomic studies confirmed a Th1 signature in CD4+ T cells from synovial fluid. The regulatory gene expression signature was preserved in Tregs, even those exhibiting Th1 polarization. These Th1-like Tregs maintained Treg-specific methylation patterns and suppressive function, supporting the stability of this Treg population in the joint. Although synovial fluid CD4+ T cells displayed an overall Th1 phenotype, scRNA-Seq uncovered heterogeneous effector and regulatory subpopulations, including IFN-induced Tregs, peripheral helper T cells, and cytotoxic CD4+ T cells. In conclusion, oligo JIA is characterized by Th1 polarization that encompasses Tregs but does not compromise their regulatory identity. Targeting Th1-driven inflammation and augmenting Treg function may represent important therapeutic approaches in oligo JIA.

Th17-Related Cytokines as Potential Discriminatory Markers between Neuromyelitis Optica (Devic's Disease) and Multiple Sclerosis-A Review

Multiple sclerosis (MS) and Devic’s disease (NMO; neuromyelitis optica) are autoimmune, inflammatory diseases of the central nervous system (CNS), the etiology of which remains unclear. It is a serious limitation in the treatment of these diseases. The resemblance of the clinical pictures of these two conditions generates a partial possibility of introducing similar treatment, but on the other hand, a high risk of misdiagnosis. Therefore, a better understanding and comparative characterization of the immunopathogenic mechanisms of each of these diseases are essential to improve their discriminatory diagnosis and more effective treatment. In this review, special attention is given to Th17 cells and Th17-related cytokines in the context of their potential usefulness as discriminatory markers for MS and NMO. The discussed results emphasize the role of Th17 immune response in both MS and NMO pathogenesis, which, however, cannot be considered without taking into account the broader perspective of immune response mechanisms.

Cytokines, Hormones and Cellular Regulatory Mechanisms Favoring Successful Reproduction

Its semi-allogeneic nature renders the conceptus vulnerable to attack by the maternal immune system. Several protective mechanisms operate during gestation to correct the harmful effects of anti-fetal immunity and to support a healthy pregnancy outcome. Pregnancy is characterized by gross alterations in endocrine functions. Progesterone is indispensable for pregnancy and humans, and it affects immune functions both directly and via mediators. The progesterone-induced mediator - PIBF - acts in favor of Th2-type immunity, by increasing Th2 type cytokines production. Except for implantation and parturition, pregnancy is characterized by a Th2-dominant cytokine pattern. Progesterone and the orally-administered progestogen dydrogesterone upregulate the production of Th2-type cytokines and suppress the production of Th1 and Th17 cytokine production in vitro. This is particularly relevant to the fact that the Th1-type cytokines TNF-α and IFN-γ and the Th17 cytokine IL-17 have embryotoxic and anti-trophoblast activities. These cytokine-modulating effects and the PIBF-inducing capabilities of dydrogesterone may contribute to the demonstrated beneficial effects of dydrogesterone in recurrent spontaneous miscarriage and threatened miscarriage. IL-17 and IL-22 produced by T helper cells are involved in allograft rejection, and therefore could account for the rejection of paternal HLA-C-expressing trophoblast. Th17 cells (producing IL-17 and IL-22) and Th22 cells (producing IL-22) exhibit plasticity and could produce IL-22 and IL-17 in association with Th2-type cytokines or with Th1-type cytokines. IL-17 and IL-22 producing Th cells are not harmful for the conceptus, if they also produce IL-4. Another important protective mechanism is connected with the expansion and action of regulatory T cells, which play a major role in the induction of tolerance both in pregnant women and in tumour-bearing patients. Clonally-expanded Treg cells increase at the feto-maternal interface and in tumour-infiltrating regions. While in cancer patients, clonally-expanded Treg cells are present in peripheral blood, they are scarce in pregnancy blood, suggesting that fetal antigen-specific tolerance is restricted to the foeto-maternal interface. The significance of Treg cells in maintaining a normal materno-foetal interaction is underlined by the fact that miscarriage is characterized by a decreased number of total effector Treg cells, and the number of clonally-expanded effector Treg cells is markedly reduced in preeclampsia. In this review we present an overview of the above mechanisms, attempt to show how they are connected, how they operate during normal gestation and how their failure might lead to pregnancy pathologies.

Altered Distribution of Circulating T Follicular Helper-Like Cell Subsets in Rheumatoid Arthritis Patients

Objective: Recent studies on follicular regulatory T (Tfr) and follicular helper T (Tfh) cells suggest that they may participate in the pathogenesis of rheumatoid arthritis (RA). Here, we examine Tfr-like and Tfh-like cells and their subsets in RA and assess the correlations between these subsets with B cells and cytokines related to the pathogenesis of RA and their clinical significance.

Methods: The study population consisted of 18 healthy controls and 47 RA patients (17 new onset, 57.00 ± 11.73 years; 30 treated RA patients, 57.56 ± 1.97 years). Disease activity scores in 28 joints were calculated. The positive rates of rheumatoid factor (RF) and anticyclic citrullinated peptide antibodies (anti-CCP) were 82.9 and 89.4%, respectively. Cell subsets were analyzed using flow cytometry, and serum cytokine levels were measured using cytometric bead array.

Results: Tfh-like and PD-1⁺ Tfh-like cells were elevated, and the distribution of Tfh-like cell subsets was altered with increased Tfh17-like and Tfh1/17-like cells in RA patients. The receiver operating characteristics curves for Tfh-like, Tfh17-like, Tfh1/17-like, and PD-1⁺ Tfh-like cells indicate improved RA diagnostic potential. RA patients had decreased regulatory T (Treg), Tfr-like, and memory Tfr-like (mTfr-like) cells and increased Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios. Tfh-like cells and their subsets, including Tfh1-like, Tfh2-like, Tfh1/17-like, and PD-1⁺ Tfh-like cells, were positively correlated with B cells. Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios were positively correlated with B cells in new-onset RA. Interleukin (IL)-2, IL-4, IL-17, interferon-γ, and tumor necrosis factor-α were positively correlated with Tfr-like and mTfr-like cells. IL-2 and IL-10 were positively correlated with Tfh-like and Tfh2-like cells. IL-4 was positively correlated with Tfh-like cells.

Conclusions: Tfh-like and PD-1⁺ Tfh-like cells are increased, whereas Treg, Tfr-like, and mTfr-like cells are decreased in RA, leading to an imbalance in Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios. Tfh-like cells and a portion of their subsets as well as Tfh-like/Treg, Tfh-like/Tfr-like, and Tfh-like/mTfr-like cell ratios are closely related to B cells. Dysfunction of cell subsets leads to abnormal levels of cytokines involved in the pathogenesis of RA. The altered distributions of Tfh-like cell subsets, especially Tfh1/17-like cells, represent potential therapeutic targets for treatment of RA.

Mycobacterium tuberculosis RpfE-Induced Prostaglandin E2 in Dendritic Cells Induces Th1/Th17 Cell Differentiation

Prostaglandin E2 (PGE2) is an important biological mediator involved in the defense against Mycobacterium tuberculosis (Mtb) infection. Currently, there are no reports on the mycobacterial components that regulate PGE2 production. Previously, we have reported that RpfE-treated dendritic cells (DCs) effectively expanded the Th1 and Th17 cell responses simultaneously; however, the mechanism underlying Th1 and Th17 cell differentiation is unclear. Here, we show that PGE2 produced by RpfE-activated DCs via the MAPK and cyclooxygenase 2 signaling pathways induces Th1 and Th17 cell responses mainly via the EP4 receptor. Furthermore, mice administered intranasally with PGE2 displayed RpfE-induced antigen-specific Th1 and Th17 responses with a significant reduction in bacterial load in the lungs. Furthermore, the addition of optimal PGE2 amount to IL-2-IL-6-IL-23p19-IL-1β was essential for promoting differentiation into Th1/Th17 cells with strong bactericidal activity. These results suggest that RpfE-matured DCs produce PGE2 that induces Th1 and Th17 cell differentiation with potent anti-mycobacterial activity.

Ganoderma lucidum: A potential source to surmount viral infections through β-glucans immunomodulatory and triterpenoids antiviral properties

Ganoderma lucidum (G. lucidum) polysaccharides and triterpenoids are the major bioactive compounds and have been used as traditional medicine for ancient times. Massive demands of G. lucidum have fascinated the researchers towards its application as functional food, nutraceutical and modern medicine owing to wide range of application in various diseases include immunomodulators, anticancer, antiviral, antioxidant, cardioprotective, hepatoprotective. G. lucidum polysaccharides exhibit immunomodulatory properties through boosting the action of antigen-presenting cells, mononuclear phagocyte system, along with humoral and cellular immunity. β-Glucans isolated from G. lucidum are anticipated to produce an immune response through pathogen associated molecular patterns (PAMPs). β-Glucans after binding with dectin-1 receptor present on different cells include macrophages, monocytes, dendritic cells and neutrophils produce signal transduction that lead to trigger the mitogen-activated protein kinases (MAPKs), T cells and Nuclear factor-κB (NF-κB) that refer to cytokines production and contributing to immune response. While triterpenoids produce antiviral effects through inhibiting various enzymes like neuraminidase, HIV-protease, DENV2 NS2B-NS3 protease and HSV multiplication. Polysaccharides and triterpenoids adjunct to other drugs exhibit potential action in prevention and treatment of various diseases. Immunomodulators and antiviral properties of this mushroom could be a potential source to overcome this current pandemic outbreak.

Human T-Cell Cloning by Limiting Dilution

Human T cells represent a heterogeneous population, including cells with different phenotypical and function properties. Despite, in the last years, several technologies were developed to investigate phenotypical properties of T cells at single cell level, in vitro T cell clone 's culture remains the only way to perform functional study on T cells at single cell levels. Here, we describe the method to obtain human T cell clones by limiting dilution in the presence of feeder cells and to maintain them in culture for further investigations.

Identification and Purification of Human Memory T Helper Cells from Peripheral Blood

T helper (Th) cells are involved in various physiopathological systems, including response to infections, vaccination, cancer, and autoimmunity. The isolation of viable human Th cells is a procedure that allows a broad study of both phenotypical and functional features of each Th subset, and thus, it is necessary to study these cells in different contexts. In particular, the purification of human memory Th cells from peripheral blood is preparatory for further complex experiments on these cells, such as global transcriptional analysis, coculture assays, silencing experiments, and drug assays.Here, we describe the method for the identification and isolation of pure memory human Th1, Th2, Th17, Th1/17, and T regulatory cells, derived from peripheral blood mononuclear cells. Moreover, we show the purity of each purified Th subset, verified by the analysis of specific transcription factors.

The heterogeneous human memory CCR6+ T helper-17 populations differ in T-bet and cytokine expression but all activate synovial fibroblasts in an IFNγ-independent manner

BACKGROUND

Chronic synovial inflammation is an important hallmark of inflammatory arthritis, but the cells and mechanisms involved are incompletely understood. Previously, we have shown that CCR6+ memory T-helper (memTh) cells and synovial fibroblasts (SF) activate each other in a pro-inflammatory feedforward loop, which potentially drives persistent synovial inflammation in inflammatory arthritis. However, the CCR6+ memTh cells are a heterogeneous population, containing Th17/Th22 and Th17.1 cells. Currently, it is unclear which of these subpopulations drive SF activation and how they should be targeted. In this study, we examined the individual contribution of these CCR6+ memTh subpopulations to SF activation and examined ways to regulate their function.

METHODS

Th17/Th22 (CXCR3-CCR4+), Th17.1 (CXCR3+CCR4-), DP (CXCR3+CCR4+), and DN (CXCR3-CCR4-) CCR6+ memTh, cells sorted from PBMC of healthy donors or treatment-naïve early rheumatoid arthritis (RA) patients, were cocultured with SF from RA patients with or without anti-IL17A, anti-IFNγ, or 1,25(OH)2D3. Cultures were analyzed by RT-PCR, ELISA, or flow cytometry.

RESULTS

Th17/Th22, Th17.1, DP, and DN cells equally express RORC but differ in production of TBX21 and cytokines like IL-17A and IFNγ. Despite these differences, all the individual CCR6+ memTh subpopulations, both from healthy individuals and RA patients, were more potent in activating SF than the classical Th1 cells. SF activation was partially inhibited by blocking IL-17A, but not by inhibiting IFNγ or TBX21. However, active vitamin D inhibited the pathogenicity of all subpopulations leading to suppression of SF activation.

CONCLUSIONS

Human CCR6+ memTh cells contain several subpopulations that equally express RORC but differ in TBX21, IFNγ, and IL-17A expression. All individual Th17 subpopulations are more potent in activating SF than classical Th1 cells in an IFNγ-independent manner. Furthermore, our data suggest that IL-17A is not dominant in this T cell-SF activation loop but that a multiple T cell cytokine inhibitor, such as 1,25(OH)2D3, is able to suppress CCR6+ memTh subpopulation-driven SF activation.

Adaptive immunity in the joint of rheumatoid arthritis

Adaptive immunity plays central roles in the pathogenesis of rheumatoid arthritis (RA), as it is regarded as an autoimmune disease. Clinical investigations revealed infiltrations of B cells in the synovium, especially those with ectopic lymphoid neogenesis, associate with disease severity. While some B cells in the synovium differentiate into plasma cells producing autoantibodies such as anti-citrullinated protein antibody, others differentiate into effector B cells producing proinflammatory cytokines and expressing RANKL. Synovial B cells might also be important as antigen-presenting cells. Synovial T cells are implicated in the induction of antibody production as well as local inflammation. In the former, a recently identified CD4 T cell subset, peripheral helper T (Tph), which is characterized by the expression of PD-1 and production of CXCL13 and IL-21, is implicated, while the latter might be mediated by Th1-like CD4 T cell subsets that can produce multiple proinflammatory cytokines, including IFN-γ, TNF-α, and GM-CSF, and express cytotoxic molecules, such as perforin, granzymes and granulysin. CD8 T cells in the synovium are able to produce large amount of IFN-γ. However, the involvement of those lymphocytes in the pathogenesis of RA still awaits verification. Their antigen-specificity also needs to be clarified.

Different T cell related immunological profiles in COVID-19 patients compared to healthy controls

In various pathological conditions, cellular immunity plays an important role in immune responses. Amongimmunecells, T lymphocytes pdomotecellular and humoralresponses as well as innate immunity. Therefore, careful investigation of these cells has a significant impact on accurate knowledge in COVID-19diseasepathogenesis. In current research, the frequency and function of various T lymphocytes involved in immune responses examined in SARS-CoV-2 patients with various disease severity compared to normal subjects. In order to make an accurate comparison among patients with various disease severity, this study was performed on asymptomatic recovered cases (n = 20), ICU hospitalized patients (n = 30), non-ICU hospitalized patients (n = 30), and normal subjects (n = 20). To precisely evaluate T cells activity following purification, their cytokine secretion activity was examined. Similarly, immediately after purification of Treg cells, their inhibitory activity on T cells was investigated. The results showed that COVID-19 patients with severe disease (ICU hospitalized patients) not only had a remarkable increase in Th1 and Th17 but also a considerable decrease in Th2 and Treg cells. More importantly, as the IL-17 and IFN-γ secretion was sharply increased in severe disease, the secretion of IL-10 and IL-4 was decreased. Furthermore, the inhibitory activity of Treg cells was reduced in severe disease patients in comparison to other groups. In severe COVID-19 disease, current findings indicate when the inflammatory arm of cellular immunity is significantly increased, a considerable reduction in anti-inflammatory and regulatory arm occurred.

Association between long noncoding RNA taurine-upregulated gene 1 and microRNA-377 in vitiligo

BACKGROUND

Taurine-upregulated gene 1 (TUG1) is one of the long noncoding RNAs (lncRNAs) that plays a role in melanogenesis. MicroRNA-377 (miRNA-377) is a conserved noncoding RNA that regulates angiogenesis and promotes oxidative stress. Peroxisome proliferator-activated receptors (PPARs) are components of the nuclear hormone receptor superfamily. PPAR-γ activators stimulate melanogenesis. Interleukin (IL)-17 has been implicated in the pathogenesis of several immunological diseases. This work aimed at detecting the expression levels of lncRNA TUG1, miRNA-377, PPAR-γ, and IL-17 among vitiligo subjects and to investigate their possible role in the pathogenesis of vitiligo.

METHODS

This study was conducted on 30 healthy controls and 30 vitiligo patients. LncRNA TUG1 and miRNA-377 were detected in serum by real-time polymerase chain reaction (PCR). Also, expressions of PPAR-γ and IL-17 were assessed in tissue by real-time PCR.

RESULTS

LncRNA TUG1 and PPAR-γ levels were significantly downregulated in the vitiligo group compared with the control group. On the other hand, miRNA-377 and IL-17 were significantly upregulated in the vitiligo group compared with the control group.

CONCLUSION

This study demonstrated the dysregulated expressions of lncRNA TUG1 and miRNA-377 in patients with vitiligo suggesting that both contributed to the pathogenesis of vitiligo that might be through PPAR-γ downregulation and IL-17 upregulation.

Th17 Cells Contribute to the Pathology of Autoimmune Hypophysitis

Autoimmune hypophysitis is classified as primary if its origin is idiopathic and secondary if it develops as a consequence of treatment with immune checkpoint inhibitors. Expanding use of immunotherapy has been paralleled by the increasing hypophysitis prevalence. However, understanding of the immune responses driving the disease remains limited. Using a mouse model of primary hypophysitis, we have identified CD4⁺ T lymphocytes to be the main pituitary-infiltrating immune cell population. Functional analysis showed that they display a Th17 and Th1/Th17 phenotype. To examine involvement of proinflammatory Th1, Th17, and Th1/17 subsets in hypophysitis, we have isolated RNA from the formalin-fixed paraffin-embedded pituitary specimens from 16 hypophysitis patients (three of whom had hypophysitis secondary to immune checkpoint inhibitors), 10 patients with adenoma, and 23 normal pituitaries obtained at autopsy. Transcript levels of IFN-γ, IL-17A, IL-4, IL-10, TGF-β, CD4, CD8α, and class II MHC transactivator were analyzed by the reverse transcription-quantitative PCR (RT-qPCR). Pituitary glands of patients with hypophysitis showed significantly higher IL-17A, CD4, and class II MHC transactivator mRNA levels compared with adenoma and normal pituitaries. All three secondary hypophysitis patients showed detectable IL-17A levels, but other cytokines were not detected in their pituitaries. Levels of IFN-γ, IL-4, IL-10, and TGF-β did not differ between the groups. TGF-β transcript was found in significantly fewer hypophysitis pituitaries (2 out of 16) compared with adenoma (7 out of 10) and normal pituitaries (11 out of 23). Presence of TGF-β in two hypophysitis patients was associated with significantly lower IL-17A mRNA levels compared with hypophysitis patients with no detectable TGF-β (p = 0.03).

Multiple sclerosis patients have reduced resting and increased activated CD4+CD25+FOXP3+T regulatory cells

Resting and activated subpopulations of CD4⁺CD25⁺CD127^loT regulatory cells (Treg) and CD4⁺CD25⁺CD127⁺ effector T cells in MS patients and in healthy individuals were compared. Peripheral blood mononuclear cells isolated using Ficoll Hypaque were stained with monoclonal antibodies and analysed by flow cytometer. CD45RA and Foxp3 expression within CD4⁺ cells and in CD4⁺CD25⁺CD127^loT cells identified Population I; CD45RA⁺Foxp3⁺, Population II; CD45RA⁻Foxp3^hi and Population III; CD45RA⁻Foxp3⁺ cells. Effector CD4⁺CD127⁺ T cells were subdivided into Population IV; memory /effector CD45RA⁻ CD25⁻Foxp3⁻ and Population V; effector naïve CD45RA⁺CD25⁻Foxp3⁻CCR7⁺ and terminally differentiated RA⁺ (TEMRA) effector memory cells. Chemokine receptor staining identified CXCR3⁺Th1-like Treg, CCR6⁺Th17-like Treg and CCR7⁺ resting Treg. Resting Treg (Population I) were reduced in MS patients, both in untreated and treated MS compared to healthy donors. Activated/memory Treg (Population II) were significantly increased in MS patients compared to healthy donors. Activated effector CD4⁺ (Population IV) were increased and the naïve/ TEMRA CD4⁺ (Population V) were decreased in MS compared to HD. Expression of CCR7 was mainly in Population I, whereas expression of CCR6 and CXCR3 was greatest in Populations II and intermediate in Population III. In MS, CCR6⁺Treg were lower in Population III. This study found MS is associated with significant shifts in CD4⁺T cells subpopulations. MS patients had lower resting CD4⁺CD25⁺CD45RA⁺CCR7⁺ Treg than healthy donors while activated CD4⁺CD25^hiCD45RA⁻Foxp3^hiTreg were increased in MS patients even before treatment. Some MS patients had reduced CCR6⁺Th17-like Treg, which may contribute to the activity of MS.