Regulatory T cells

Regulatory T cells as a possible new target in epilepsy?

Epilepsy is a complex chronic brain disorder with diverse clinical features that can be caused by various triggering events, such as infections, head trauma, or stroke. During epileptogenesis, various abnormalities are observed, such as altered cellular homeostasis, imbalance of neurotransmitters, tissue changes, and the release of inflammatory mediators, which in combination lead to spontaneous recurrent seizures. Regulatory T cells (Tregs), a subtype of CD4+Foxp3+ T cells, best known for their key function in immune suppression, also seem to play a role in attenuating neurodegeneration and suppressing pathological inflammation in several brain disease states. Considering that epilepsy is also highly associated with neuronal damage and neuroinflammation, modulation of Tregs may be an interesting way to modify the disease course of epilepsy and needs further investigation. In this review, we will describe the currently available information on Tregs in epilepsy.

The roles of Th cells in myocardial infarction

Myocardial infarction, commonly known as a heart attack, is a serious condition caused by the abrupt stoppage of blood flow to a part of the heart, leading to tissue damage. A significant aspect of this condition is reperfusion injury, which occurs when blood flow is restored but exacerbates the damage. This review first addresses the role of the innate immune system, including neutrophils and macrophages, in the cascade of events leading to myocardial infarction and reperfusion injury. It then shifts focus to the critical involvement of CD4+ T helper cells in these processes. These cells, pivotal in regulating the immune response and tissue recovery, include various subpopulations such as Th1, Th2, Th9, Th17, and Th22, each playing a unique role in the pathophysiology of myocardial infarction and reperfusion injury. These subpopulations contribute to the injury process through diverse mechanisms, with cytokines such as IFN-γ and IL-4 influencing the balance between tissue repair and injury exacerbation. Understanding the interplay between the innate immune system and CD4+ T helper cells, along with their cytokines, is crucial for developing targeted therapies to mitigate myocardial infarction and reperfusion injury, ultimately improving outcomes for cardiac patients.

Technical pitfalls when collecting, cryopreserving, thawing, and stimulating human T-cells

The collection, cryopreservation, thawing, and culture of peripheral blood mononuclear cells (PBMCs) can profoundly influence T cell viability and immunogenicity. Gold-standard PBMC processing protocols have been developed by the Office of HIV/AIDS Network Coordination (HANC); however, these protocols are not universally observed. Herein, we have explored the current literature assessing how technical variation during PBMC processing can influence cellular viability and T cell immunogenicity, noting inconsistent findings between many of these studies. Amid the mounting concerns over scientific replicability, there is growing acknowledgement that improved methodological rigour and transparent reporting is required to facilitate independent reproducibility. This review highlights that in human T cell studies, this entails adopting stringent standardised operating procedures (SOPs) for PBMC processing. We specifically propose the use of HANC's Cross-Network PBMC Processing SOP, when collecting and cryopreserving PBMCs, and the HANC member network International Maternal Pediatric Adolescent AIDS Clinical Trials (IMPAACT) PBMC Thawing SOP when thawing PBMCs. These stringent and detailed protocols include comprehensive reporting procedures to document unavoidable technical variations, such as delayed processing times. Additionally, we make further standardisation and reporting recommendations to minimise and document variability during this critical experimental period. This review provides a detailed overview of the challenges inherent to a procedure often considered routine, highlighting the importance of carefully considering each aspect of SOPs for PBMC collection, cryopreservation, thawing, and culture to ensure accurate interpretation and comparison between studies.

An immunocytokine consisting of a TNFR2 agonist and TNFR2 scFv enhances the expansion of regulatory T cells through TNFR2 clustering

Regulatory T cells (Tregs) are lymphocytes that play a central role in peripheral immune tolerance. Tregs are promising targets for the prevention and suppression of autoimmune diseases, allergies, and graft-versus-host disease, and treatments aimed at regulating their functions are being developed. In this study, we created a new modality consisting of a protein molecule that suppressed excessive immune responses by effectively and preferentially expanding Tregs. Recent studies reported that tumor necrosis factor receptor type 2 (TNFR2) expressed on Tregs is involved in the proliferation and activation of Tregs. Therefore, we created a functional immunocytokine, named TNFR2-ICK-Ig, consisting of a fusion protein of an anti-TNFR2 single-chain Fv (scFv) and a TNFR2 agonist TNF-α mutant protein, as a new modality that strongly enhances TNFR2 signaling. The formation of agonist-receptor multimerization (TNFR2 cluster) is effective for the induction of a strong TNFR2 signal, similar to the TNFR2 signaling mechanism exhibited by membrane-bound TNF. TNFR2-ICK-Ig improved the TNFR2 signaling activity and promoted TNFR2 cluster formation compared to a TNFR2 agonist TNF-α mutant protein that did not have an immunocytokine structure. Furthermore, the Treg expansion efficiency was enhanced. TNFR2-ICK-Ig promotes its effects via scFv, which crosslinks receptors whereas the agonists transmit stimulatory signals. Therefore, this novel molecule expands Tregs via strong TNFR2 signaling by the formation of TNFR2 clustering.

Immune Homeostasis: A Novel Example of Teamwork

All living organisms must maintain homeostasis to survive, reproduce, and pass their traits on to the next generation. If homeostasis is not maintained, it can result in various diseases and ultimately lead to death. Physiologists have coined the term "homeostasis" to describe this process. With the emergence of immunology as a separate branch of medicine, the concept of immune homeostasis has been introduced. Maintaining immune homeostasis is crucial to support overall homeostasis through different immunological and non-immunological routes. Any changes in the immune system can lead to chronic inflammatory or autoimmune diseases, immunodeficiency diseases, frequent infections, and cancers. Ongoing scientific advances are exploring new avenues in immunology and immune homeostasis maintenance. This chapter introduces the concept of immune homeostasis and its maintenance through different mechanisms.

Bivalent structure of a TNFR2-selective and agonistic TNF-α mutein Fc-fusion protein enhances the expansion activity of regulatory T cells

Recently, TNF receptor type 2 (TNFR2) signaling was found to be involved in the proliferation and activation of regulatory T cells (Tregs), a subpopulation of lymphocytes that suppress immune responses. Tregs mediate peripheral immune tolerance, and the disruption of their functions causes autoimmune diseases or allergy. Therefore, cell expanders or regulators of Tregs that control immunosuppressive activity can be used to treat these diseases. We focused on TNFR2, which is preferentially expressed on Tregs, and created tumor necrosis factor-α (TNF-α) muteins that selectively activate TNFR2 signaling in mice and humans, termed R2agoTNF and R2-7, respectively. In this study, we attempted to optimize the structure of muteins to enhance their TNFR2 agonistic activity and stability in vivo by IgG-Fc fusion following single-chain homo-trimerization. The fusion protein, scR2agoTNF-Fc, enhanced the expansion of CD4+CD25+ Tregs and CD4+Foxp3+ Tregs and contributed to their immunosuppressive activity ex vivo and in vivo in mice. The prophylactic administration of scR2agoTNF-Fc suppressed inflammation in contact hypersensitivity and arthritis mouse models. Furthermore, scR2-7-Fc preferentially expanded Tregs in human peripheral blood mononuclear cells via TNFR2. These TNFR2 agonist-Fc fusion proteins, which have bivalent structures, are novel Treg expanders.

Cells resident to precision templated 40-µm pore scaffolds generate small extracellular vesicles that affect CD4+ T cell phenotypes through regulatory TLR4 signaling

Precision porous templated scaffolds (PTS) are a hydrogel construct of uniformly sized interconnected spherical pores that induce a pro-healing response (reducing the foreign body reaction, FBR) exclusively when the pores are 30-40µm in diameter. Our previous work demonstrated the necessity of Tregs in the maintenance of PTS pore size specific differences in CD4+ T cell phenotype. Work here characterizes the role of Tregs in the responses to implanted 40µm and 100µm PTS using WT and FoxP3+ cell (Treg) depleted mice. Proteomic analyses indicate that integrin signaling, monocytes/macrophages, cytoskeletal remodeling, inflammatory cues, and vesicule endocytosis may participate in Treg activation and the CD4+ T cell equilibrium modulated by PTS resident cell-derived small extracellular vesicles (sEVs). The role of MyD88-dependent and MyD88-independent TLR4 activation in PTS cell-derived sEV-to-T cell signaling is quantified by treating WT, TLR4ko, and MyD88ko splenic T cells with PTS cell-derived sEVs. STAT3 and mTOR are identified as mechanisms for further study for pore-size dependent PTS cell-derived sEV-to-T cell signaling. STATEMENT OF SIGNIFICANCE: Unique cell populations colonizing only within 40µm pore size PTS generate sEVs that resolve inflammation by modifying CD4+ T cell phenotypes through TLR4 signaling.

The potential of regulatory T cell-based therapies for alopecia areata

Cytotoxic T lymphocyte has been a concern for the etiopathogenesis of alopecia areata (AA), some recent evidence suggests that the regulatory T (T_reg) cell deficiency is also a contributing factor. In the lesional scalp of AA, T_reg cells residing in the follicles are impaired, leading to dysregulated local immunity and hair follicle (HF) regeneration disorders. New strategies are emerging to modulate T_reg cells' number and function for autoimmune diseases. There is much interest to boost T_reg cells in AA patients to suppress the abnormal autoimmunity of HF and stimulate hair regeneration. With few satisfactory therapeutic regimens available for AA, T_reg cell-based therapies could be the way forward. Specifically, CAR-T_reg cells and novel formulations of low-dose IL-2 are the alternatives.

Immune responses in diabetic nephropathy: Pathogenic mechanisms and therapeutic target

Diabetic nephropathy (DN) is a chronic, inflammatory disease affecting millions of diabetic patients worldwide. DN is associated with proteinuria and progressive slowing of glomerular filtration, which often leads to end-stage kidney diseases. Due to the complexity of this metabolic disorder and lack of clarity about its pathogenesis, it is often more difficult to diagnose and treat than other kidney diseases. Recent studies have highlighted that the immune system can inadvertently contribute to DN pathogenesis. Cells involved in innate and adaptive immune responses can target the kidney due to increased expression of immune-related localization factors. Immune cells then activate a pro-inflammatory response involving the release of autocrine and paracrine factors, which further amplify inflammation and damage the kidney. Consequently, strategies to treat DN by targeting the immune responses are currently under study. In light of the steady rise in DN incidence, this timely review summarizes the latest findings about the role of the immune system in the pathogenesis of DN and discusses promising preclinical and clinical therapies.

Subtype-Specific Tumour Immune Microenvironment in Risk of Recurrence of Ductal Carcinoma In Situ: Prognostic Value of HER2

Increasing evidence suggests that the significance of the tumour immune microenvironment (TIME) for disease prognostication in invasive breast carcinoma is subtype-specific but equivalent studies in ductal carcinoma in situ (DCIS) are limited. The purpose of this paper is to review the existing data on immune cell composition in DCIS in relation to the clinicopathological features and molecular subtype of the lesion. We discuss the value of infiltration by various types of immune cells and the PD-1/PD-L1 axis as potential markers of the risk of recurrence. Analysis of the literature available in PubMed and Medline databases overwhelmingly supports an association between densities of infiltrating immune cells, traits of immune exhaustion, the foci of microinvasion, and overexpression of HER2. Moreover, in several studies, the density of immune infiltration was found to be predictive of local recurrence as either in situ or invasive cancer in HER2-positive or ER-negative DCIS. In light of the recently reported first randomized DCIS trial, relating recurrence risk with overexpression of HER2, we also include a closing paragraph compiling the latest mechanistic data on a functional link between HER2 and the density/composition of TIME in relation to its potential value in the prognostication of the risk of recurrence.

The Association between Regulatory T Cell Subpopulations and Severe Pneumonia Post Renal Transplantation

Severe pneumonia accounts for the majority of morbidity and mortality in renal allograft recipients due to immunosuppressant maintenance. Regulatory T cells (Tregs), which are involved in tackling infections under immunosuppressive conditions, are rarely uncovered. We aimed to investigate the relationship between various Treg subpopulations and severe pneumonia after kidney transplantation (KTx). KTx recipients with pneumonia were divided into severe pneumonia and mild pneumonia groups. The frequencies and absolute numbers (Ab No.) of total Tregs (CD4+CD25+FoxP3+), six subsets of Tregs (Helios+/-, CD39+/-, and CD45RA+/-), and T cells, B cells, and NK cells were assessed from peripheral blood via flow cytometry using the $t$ or Mann-Whitney test and receiver operating curve analysis. We also determined the median fluorescence intensity (MFI) of human leukocyte antigen- (HLA-) DR on monocytes and CD64 on neutrophils. Logistic regression was used to identify the risk factors of disease progression, and Pearson’s correlation analysis was performed to identify relationships between the measured immune indices and patients’ clinical information. Our research indicated that Treg subpopulations were strongly associated with severe pneumonia progression post KTx. Based on the monitoring of Treg subpopulations, better-individualized prevention and therapy might be achieved for patients with severe pneumonia post KTx.

Dysregulated Immunity in Pulmonary Hypertension: From Companion to Composer

Pulmonary hypertension (PH) represents a grave condition associated with high morbidity and mortality, emphasizing a desperate need for innovative and targeted therapeutic strategies. Cumulative evidence suggests that inflammation and dysregulated immunity interdependently affect maladaptive organ perfusion and congestion as hemodynamic hallmarks of the pathophysiology of PH. The role of altered cellular and humoral immunity in PH gains increasing attention, especially in pulmonary arterial hypertension (PAH), revealing novel mechanistic insights into the underlying immunopathology. Whether these immunophysiological aspects display a universal character and also hold true for other types of PH (e.g., PH associated with left heart disease, PH-LHD), or whether there are unique immunological signatures depending on the underlying cause of disease are points of consideration and discussion. Inflammatory mediators and cellular immune circuits connect the local inflammatory landscape in the lung and heart through inter-organ communication, involving, e.g., the complement system, sphingosine-1-phosphate (S1P), cytokines and subsets of, e.g., monocytes, macrophages, natural killer (NK) cells, dendritic cells (DCs), and T- and B-lymphocytes with distinct and organ-specific pro- and anti-inflammatory functions in homeostasis and disease. Perivascular macrophage expansion and monocyte recruitment have been proposed as key pathogenic drivers of vascular remodeling, the principal pathological mechanism in PAH, pinpointing toward future directions of anti-inflammatory therapeutic strategies. Moreover, different B- and T-effector cells as well as DCs may play an important role in the pathophysiology of PH as an imbalance of T-helper-17-cells (T_H17) activated by monocyte-derived DCs, a potentially protective role of regulatory T-cells (T_reg) and autoantibody-producing plasma cells occur in diverse PH animal models and human PH. This article highlights novel aspects of the innate and adaptive immunity and their interaction as disease mediators of PH and its specific subtypes, noticeable inflammatory mediators and summarizes therapeutic targets and strategies arising thereby.

Type I Interferons Enhance the Repair of Ultraviolet Radiation-Induced DNA Damage and Regulate Cutaneous Immune Suppression

Type I interferons (IFNs) are important enhancers of immune responses which are downregulated in human cancers, including skin cancer. Solar ultraviolet (UV) B radiation is a proven environmental carcinogen, and its exposure contributes to the high prevalence of skin cancer. The carcinogenic effects of UV light can be attributed to the formation of cyclobutane pyrimidine dimers (CPD) and errors in the repair and replication of DNA. Treatment with a single dose of UVB (100 mJ/cm2) upregulated IFNα and IFNβ in the skin of C57BL/6 mice. IFNα and IFNβ were predominantly produced by CD11b+ cells. In mice lacking the type I IFN receptor 1 (IFNAR1), the repair of CPD following cutaneous exposure to a single dose of UVB (100 mJ/cm2) was decreased. UVB induced the expression of the DNA repair gene xeroderma pigmentosum A (XPA) in wild-type (WT) mice. In contrast, such treatment in IFNAR1 (IFNAR1-/-) mice downregulated XPA. A local UVB regimen consisting of UVB radiation (150 mJ/cm2) for 4 days followed by sensitization with hapten 2,4, dinitrofluorobenzene (DNFB) resulted in significant suppression of immune responses in both WT and IFNAR1-/- mice. However, there were significantly higher CD4+CD25+Foxp3+ regulatory T-cells in the draining lymph nodes of IFNAR1-/- mice in comparison to WT mice. Overall, our studies reveal a previously unknown action of type I IFNs in the repair of photodamage and the prevention of UVB-induced immune suppression.

Transcriptional Heterogeneity and the Microbiome of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphomas (CTCL) presents with substantial clinical variability and transcriptional heterogeneity. In the recent years, several studies paved the way to elucidate aetiology and pathogenesis of CTCL using sequencing methods. Several T-cell subtypes were suggested as the source of disease thereby explaining clinical and transcriptional heterogeneity of CTCL entities. Several differentially expressed pathways could explain disease progression. However, exogenous triggers in the skin microenvironment also seem to affect CTCL status. Especially Staphylococcus aureus was shown to contribute to disease progression. Only little is known about the complex microbiome patterns involved in CTCL and how microbial shifts might impact this malignancy. Nevertheless, first hints indicate that the microbiome might at least in part explain transcriptional heterogeneity and that microbial approaches could serve in diagnosis and prognosis. Shaping the microbiome could be a treatment option to maintain stable disease. Here, we review current knowledge of transcriptional heterogeneity of and microbial influences on CTCL. We discuss potential benefits of microbial applications and microbial directed therapies to aid patients with CTCL burden.

Controllers of cutaneous regulatory T cells: ultraviolet radiation and the skin microbiome

For the maintenance of homeostasis termination of immune reactions is as equally important as their induction. In this scenario regulatory T cells (Treg) play an important role. Accordingly a variety of inflammatory diseases are caused by an impairment of Treg. Hence, it is important to identify triggers by which Treg can be induced and activated, respectively. For quite a long time it is known that ultraviolet radiation can induce Treg which inhibit cutaneous immune reactions including contact hypersensitivity. Since these Treg inhibit in an antigen-specific fashion they may harbor therapeutic potential. However similar Treg can be induced also by other triggers which include vitamin D and antimicrobial peptides. Recently it was discovered that the gut microbiome controls the development of Treg in the intestine. The same may apply for the skin. Short chain fatty acids, microbiota-derived bacterial fermentation products, appear to induce and to activate Treg in the skin. Topical application of short chain fatty acids was shown to inhibit contact hypersensitivity and to reduce inflammation in the murine imiquimod-induced psoriasis-like skin inflammation model. Together, these data indicate that induction and activation of Treg may be a potential therapeutic strategy to treat inflammatory diseases in the future.

COVID-19 and Progesterone: Part 1.SARS-CoV-2, Progesterone and its potential clinical use

SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) infection is a global medical challenge. Experience based medicines and therapies are being attempted and vaccines are being developed. SARS-CoV-2 exhibits varied patterns of infection and clinical presentations with varied disease outcomes. These attributes are strongly suggestive of some variables that differ among individuals and that affect the course of SARS-CoV-2 infection and symptoms of COVID-19 (Corona Virus Disease of 2019). Sex hormones vary with ageing, between the sexes, among individuals and populations. Sex hormones are known to play a role in immunity and infections. Progesterone is a critical host factor to promote faster recovery following Influenza A virus infection. Anti-inflammatory effects of progesterone are noted. In part 1 of the current study the regulatory role of progesterone for SARS-CoV-2 infection and COVID-19 is analyzed. The role of progesterone at different stages of the SARS CoV-2 infection is investigated with respect to two types of immunity status: immune regulation and immune dysregulation. Progesterone could have various alleviating impacts from SARS-CoV-2 entry till recovery: reversing of hypoxia, stabilizing of blood pressure, controlling thrombosis, balancing electrolytes, reducing the viral load, regulation of immune responses, damage repair, and clearance of debris among others. The present research adds to the available evidence by providing a comprehensive and thorough evaluation of the regulatory role of progesterone in SARS COV-2 infection, COVID-19 pathogenesis, and immune dysregulation. The available evidence has implications for upcoming studies about pathophysiology of COVID-19, as well as the roles of progesterone and other hormones in other infectious diseases.

Biocompatibility Evolves: Phenomenology to Toxicology to Regeneration

The word "biocompatibility," is inconsistent with the observations of healing for so-called biocompatible biomaterials. The vast majority of the millions of medical implants in humans today, presumably "biocompatible," are walled off by a dense, avascular, crosslinked collagen capsule, hardly suggestive of life or compatibility. In contrast, one is now seeing examples of implant biomaterials that lead to a vascularized reconstruction of localized tissue, a biological reaction different from traditional biocompatible materials that generate a foreign body capsule. Both the encapsulated biomaterials and the reconstructive biomaterials qualify as "biocompatible" by present day measurements of biocompatibility. Yet, this new generation of materials would seem to heal "compatibly" with the living organism, where older biomaterials are isolated from the living organism by the dense capsule. This review/perspective article will explore this biocompatibility etymological conundrum by reviewing the history of the concepts around biocompatibility, today's standard methods for assessing biocompatibility, a contemporary view of the foreign body reaction and finally, a compendium of new biomaterials that heal without the foreign body capsule. A new definition of biocompatibility is offered here to address advances in biomaterials design leading to biomaterials that heal into the body in a facile manner.

Onco-Receptors Targeting in Lung Cancer via Application of Surface-Modified and Hybrid Nanoparticles: A Cross-Disciplinary Review

Lung cancer is among the most prevalent and leading causes of death worldwide. The major reason for high mortality is the late diagnosis of the disease, and in most cases, lung cancer is diagnosed at fourth stage in which the cancer has metastasized to almost all vital organs. The other reason for higher mortality is the uptake of the chemotherapeutic agents by the healthy cells, which in turn increases the chances of cytotoxicity to the healthy body cells. The complex pathophysiology of lung cancer provides various pathways to target the cancerous cells. In this regard, upregulated onco-receptors on the cell surface of tumor including epidermal growth factor receptor (EGFR), integrins, transferrin receptor (TFR), folate receptor (FR), cluster of differentiation 44 (CD44) receptor, etc. could be exploited for the inhibition of pathways and tumor-specific drug targeting. Further, cancer borne immunological targets like T-lymphocytes, myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and dendritic cells could serve as a target site to modulate tumor activity through targeting various surface-expressed receptors or interfering with immune cell-specific pathways. Hence, novel approaches are required for both the diagnosis and treatment of lung cancers. In this context, several researchers have employed various targeted delivery approaches to overcome the problems allied with the conventional diagnosis of and therapy methods used against lung cancer. Nanoparticles are cell nonspecific in biological systems, and may cause unwanted deleterious effects in the body. Therefore, nanodrug delivery systems (NDDSs) need further advancement to overcome the problem of toxicity in the treatment of lung cancer. Moreover, the route of nanomedicines’ delivery to lungs plays a vital role in localizing the drug concentration to target the lung cancer. Surface-modified nanoparticles and hybrid nanoparticles have a wide range of applications in the field of theranostics. This cross-disciplinary review summarizes the current knowledge of the pathways implicated in the different classes of lung cancer with an emphasis on the clinical implications of the increasing number of actionable molecular targets. Furthermore, it focuses specifically on the significance and emerging role of surface functionalized and hybrid nanomaterials as drug delivery systems through citing recent examples targeted at lung cancer treatment.

Brain-immune crosstalk in the treatment of major depressive disorder

A growing number of studies are pointing out the need for a conceptual shift from a brain-centered to a body-inclusive approach in mental health research. In this perspective, the link between the immune and the nervous system, which are deeply interconnected and continuously interacting, is one of the most important novel theoretical framework to investigate the biological bases of major depressive disorder and, more in general, mental illness. Indeed, depressed patients show high levels of inflammatory markers, administration of pro-inflammatory drugs triggers a depressive symptomatology and antidepressant efficacy is reduced by excessive immune system activation. A number of molecular and cellular mechanisms have been hypothesized to act as a link between the immune and brain function, thus representing potential pharmacologically targetable processes for the development of novel and effective therapeutic strategies. These include the modulation of the kynurenine pathway, the crosstalk between metabolic and inflammatory processes, the imbalance in acquired immune responses, in particular T cell responses, and the interplay between neural plasticity and immune system activation. In the personalized medicine approach, the assessment and regulation of these processes have the potential to lead, respectively, to novel diagnostic approaches for the prediction of treatment outcome according to the patient's immunological profile, and to improved efficacy of antidepressant compounds through immune modulation.

The role of regulatory T cells in the pathogenesis and treatment of prostate cancer

Despite developments in the treatment of various cancers, prostate cancer is one of the deadliest diseases known to men. Systemic therapies such as androgen deprivation, chemotherapy, and radiation therapy have not been very successful in treating this disease. Numerous studies have shown that there is a direct relationship between cancer progression and inhibition of anti-tumor immune responses that can lead to progression of various malignancies, including prostate cancer. Interestingly, CD4⁺CD25⁺FoxP3⁺ regulatory T cells significantly accumulate and increase in draining lymph nodes and PBMCs of patients with prostate cancer and other solid tumors. In vivo and in vitro studies have shown that Tregs can suppress anti-tumor responses, which is directly related to the increased risk of cancer recurrence. Tregs are essential for preserving self-tolerance and inhibiting extra immune responses harmful to the host. Since the tumor-related antigens are mainly self-antigens, Tregs could play a major role in tumor progression. Accordingly, it has discovered that prostate cancer patients with higher Tregs have poor prognosis and low survival rates. However, anti-tumor responses can be reinforced by suppression of Tregs with using monoclonal antibodies against CD25 and CTLA-4. Therefore, depleting Tregs or suppressing their functions could be one of the effective ways for prostate cancer immunotherapy. The purpose of this review is to investigate the role of Treg cells in the progression of prostate cancer and to evaluate effective strategies for the treatment of prostate cancer by regulating Treg cells.

Update on the neurodevelopmental theory of depression: is there any 'unconscious code'?

Depression is currently one of the most common psychiatric disorders and the number of patients receiving antidepressant treatment is increasing every year. Therefore, it is essential to understand the underlying mechanisms that are associated with higher prevalence of depression. The main component leading to the change in functioning, in the form of apathy, anhedonia, lack of motivation and sleep disturbances, is stress. This is the factor that in recent decades—due to the civilization speed, dynamic technological development as well as competitiveness and competition in relationships—significantly affects the psychophysical condition, which results in an increase in the prevalence of civilization diseases, including depression. To understand the mechanism of susceptibility to this disease, one should consider the significant role of the interaction between immune and nervous systems. Their joint development from the moment of conception is a matrix of later predispositions, both associated with the mobilization of the proinflammatory pathways (TNFα, IL-1β, IL-6) and associated with psychological coping with stress. Such an early development period is associated with epigenetic processes that are strongly marked in prenatal development up to 1 year of age and determinate the characteristic phenotype for various forms of pathology, including depression. Regarding the inflammatory hypothesis of depression, interleukin 17 (IL-17), among other proinflammatory cytokines, might play an important role in the development of depressive disorders. It is secreted by Th17 cells, crossed the placental barrier and acts on the brain structures of the fetus by increasing IL-17 receptor levels and affecting the intensity of its signaling in the brain.

Uniform 40-µm-pore diameter precision templated scaffolds promote a pro-healing host response by extracellular vesicle immune communication

Implanted porous precision templated scaffolds (PTS) with 40-µm spherical pores reduce inflammation and foreign body reaction (FBR) while increasing vascular density upon implantation. Larger or smaller pores, however, promote chronic inflammation and FBR. While macrophage (MØ) recruitment and polarization participates in perpetuating this pore-size-mediated phenomenon, the driving mechanism of this unique pro-healing response is poorly characterized. We hypothesized that the primarily myeloid PTS resident cells release small extracellular vesicles (sEVs) that induce pore-size-dependent pro-healing effects in surrounding T cells. Upon profiling resident immune cells and their sEVs from explanted 40-µm- (pro-healing) and 100-µm-pore diameter (inflammatory) PTS, we found that PTS pore size did not affect PTS resident immune cell population ratios or the proportion of myeloid sEVs generated from explanted PTS. However, quantitative transcriptomic assessment indicated cell and sEV phenotype were pore size dependent. In vitro experiments demonstrated the ability of PTS cell-derived sEVs to stimulate T cells transcriptionally and proliferatively. Specifically, sEVs isolated from cells inhabiting explanted 100 μm PTS significantly upregulated T_h1 inflammatory gene expression in immortalized T cells. sEVs isolated from cell inhabiting both 40- and 100-μm PTS upregulated essential T_reg transcriptional markers in both primary and immortalized T cells. Finally, we investigated the effects of T_reg depletion on explanted PTS resident cells. FoxP3+ cell depletion suggests T_regs play a unique role in balancing T cell subset ratios, thus driving host response in 40-μm PTS. These results indicate that predominantly 40-µm PTS myeloid cell-derived sEVs affect T cells through a distinct, pore-size-mediated modality.

Smoking Associated T-Cell Imbalance in Patients With Chronic Pain

INTRODUCTION

Smoking is associated with several diseases and affects the immune system. Recently, published data demonstrate an involvement of T helper 17 cells (Th17) and regulatory T cells (Tregs) in the pathogenesis of chronic pain and pain intensity. The role of these T-cell subsets in smoking patients with chronic pain is nebulous so far. We therefore analyzed Th17 cells and Tregs in smokers and nonsmokers with chronic pain.

METHODS

Analyses of T-cell subsets, mRNA expression and T-cell related cytokine profiles were done in 44 patients with chronic pain. Twenty-two of these patients were smokers. Numbers of T-cell subsets were quantified by flow cytometry. mRNA expression of the Th17- (RAR-related orphan receptor gamma) and Treg (forkhead box protein P3)-specific transcription factors was determined by quantitative real-time PCR, and levels of cytokines were measured by Human Cytokine Multiplex Immunoassay.

RESULTS

Compared to nonsmokers, smokers showed significantly enhanced pain levels. On cellular basis, the number of pro-inflammatory Th17 cells (smokers: 2.2 ± 2.5% vs. nonsmokers: 0.5 ± 0.4%; p = .04) was increased, whereas the number of anti-inflammatory Tregs (smokers: 2.5 ± 0.9% vs. nonsmokers: 3.1 ± 1.1%; p = .02) was significantly decreased, resulting in an altered Th17/Treg ratio (Th17/Treg ratio: 0.9 ± 1.0 in smokers vs. 0.2 ± 0.1 in nonsmokers; p < .01). These findings were confirmed by quantitative real-time PCR. Analyses of cytokines revealed only marginal changes.

CONCLUSIONS

In patients with chronic pain, smoking is associated with enhanced pain levels together with an imbalance of the Th17/Treg ratio. The shift of the Th17/Treg ratio toward inflammation may explain in part the increased pain intensity in these patients.

IMPLICATIONS

Smoking is associated with increased pain levels and a pro-inflammatory Th17/Treg shift. The altered Th17/Treg ratio in smoking patients with chronic pain may partly explain their increased pain intensity.

GERMAN CLINICAL TRIAL REGISTER (DRKS)

Registration Trial DRKS00005954.

Effect of arsenic trioxide on the Tregs ratio and the levels of IFN-γ, IL-4, IL-17 and TGF-β1 in the peripheral blood of severe aplastic anemia patients

Previous studies have suggested that the anticancer agent, arsenic trioxide (ATO), could attenuate T cell mediated immunity by not only inhibiting the proliferative response of T cells but by also increasing the frequency of regulatory T cells (Tregs). Furthermore, ATO represents a reasonable salvage treatment in some patients with refractory severe aplastic anemia (SAA). The current study aimed to evaluate the function of ATO on the Tregs percentage and cytokines changes in the peripheral blood mononuclear cells (PBMCs) of SAA patients.PBMCs were collected from 20 newly diagnosed SAA patients in Henan Cancer Hospital and treated with different concentrations of ATO (0, 1, 2.5, and 5 μmol/L). Then we investigated the efficacy of ATO on Tregs ratio and the levels of interferon (IFN)-γ, interleukin (IL)-4, IL-17 and transforming growth factor (TGF)-β1 in the peripheral blood of SAA patients in vitro.The results showed that ATO significantly increased the proportion of Tregs (P < .001) at 2.5 and 5 μmol/L concentrations, and the proportion of Tregs was increased with increasing ATO concentration (r = 0.524). At 1 (P = .03), 2.5 (P < .001) and 5 μmol/L (P < .001), ATO significantly up-regulated the expression levels of Foxp3 mRNA, which was positively and linearly correlated with the increase of Tregs cell-frequency (r = 0.52, 95%CI, 0.37-0.67). In addition, ATO significantly reduced the levels of IFN-γ (at 1, 2.5 and 5 μmol/L, P < .001), IL-4 (at 2.5 μmol/L, P = .009; at 5 μmol/L, P < .001), and IL-17 (at 2.5, P = .016; at 5 μmol/L, P < .001). ATO significantly reduced the levels of TGF-β1 at 5 μmol/L (P = .03), but showed no significant effects at 1 and 2.5 μmol/L (P > .05).ATO could mediate the immune regulation, which might contribute to improve hematopoietic recovery in SAA patients.

An immune gate of depression - Early neuroimmune development in the formation of the underlying depressive disorder

The prevalence of depression worldwide is increasing from year to year and constitutes a serious medical, economic and social problem. Currently, despite multifactorial risk factors and pathways contributing to depression development, a significant aspect is attributed to the inflammatory process. Cytokines are considered a factor activating the kynurenine pathway, which leads to the exhaustion of tryptophan in the tryptophan catabolite (TRYCAT) pathway. This results in the activation of potentially neuroprogressive processes and also affects the metabolism of many neurotransmitters. The immune system plays a coordinating role in mediating inflammatory process. Beginning from foetal life, dendritic cells have the ability to react to bacterial and viral antigens, stimulating T lymphocytes in a similar way to adult cells. Cytotoxicity in the prenatal period shapes the predisposition to the development of depression in adult life. Allostasis, i.e. the ability to maintain the body's balance in the face of environmental adversity through changes in its behaviour or physiology, allows the organism to survive but its consequences may be unfavourable if it lasts too long. As a result, Th lymphocytes, in particular T helper 17 cells, which play a central role in the immunity of the whole body, contribute to the development of both autoimmune diseases and psychiatric disorders including depression, as well as have an impact on the differentiation of T CD4+ cells into Th17 cells in the later development of the child's organism, which confirms the importance of the foetal period for the progression of depressive disorders.

Effect of Blocking the OX40/OX40L Signaling Pathway by siRNA Interference on Animal Experimental Study of Allergic Rhinitis

BACKGROUND

The identification of new approaches and intervention targets for the treatment of AR is urgently needed. We aimed to investigate the effect of blocking the OX40/OX40L signaling pathway by small interfering RNA (siRNA) on ovalbumin (OVA)-induced AR in a mouse model.

METHODS

After establishment of the AR model, the mice were interfered by siRNA-OX40L (experimental group), siRNA-C (negative control group), or PBS (control group). Nose scratching, sneezing and nasal discharge were observed. OX40L mRNA and protein and the IL-5, TNF-α, regulatory T cell (Treg) -specific marker Foxp3, and eosinophil (EOS) levels were analyzed.

RESULTS

The numbers of nose scratching and sneezing were significantly lower in the siRNA-OX40L-treated group (p <0.05). After the intervention of siRNA-OX40L, OX40L mRNA and protein levels were significantly inhibited (p <0.05), but the Foxp3 level was significantly increased in the experimental group (p <0.05). The IL-5 and TNF-α levels were significantly lower in the experimental group (p <0.05), and the reduction was more evident for the Th2-type cytokine IL-5 than for the Th1-type cytokine TNF-α. Few or no EOSs were found in the nasal mucosal epithelium of the experimental group (p <0.05), whereas EOS infiltration was significant in the other two groups.

CONCLUSIONS

Blockage of the OX40/OX40L signaling pathway with siRNA-OX40L interference can inhibit allergic reactions and relieve allergic symptoms in AR mice. The underlying mechanism may be related to correcting Th2 immune deviation, inducing immune tolerance, and promoting Treg production.

Macroenvironment-gene-microenvironment interactions in ultraviolet radiation-induced melanomagenesis

Cutaneous malignant melanoma is one of the few major cancers that continue to exhibit a positive rate of increase in the developed world. A wealth of epidemiological data has undisputedly implicated ultraviolet radiation (UVR) from sunlight and artificial sources as the major risk factor for melanomagenesis. However, the molecular mechanisms of this cause-and-effect relationship remain murky and understudied. Recent efforts on multiple fronts have brought unprecedented expansion of our knowledge base on this subject and it is now clear that melanoma is caused by a complex interaction between genetic predisposition and environmental exposure, primarily to UVR. Here we provide an overview of the effects of the macroenvironment (UVR) on the skin microenvironment and melanocyte-specific intrinsic (mostly genetic) landscape, which conspire to produce one of the deadliest malignancies.

Molecular aspects of depression: A review from neurobiology to treatment

Major depressive disorder (MDD), also known as unipolar depression, is one of the leading causes of disability and disease worldwide. The signs and symptoms are low self‑esteem, anhedonia, feeling of worthlessness, sense of rejection and guilt, suicidal thoughts, among others. This review focuses on studies with molecular-based approaches involving MDD to obtain an integrated, more detailed and comprehensive view of the brain changes produced by this disorder and its treatment and how the Central Nervous System (CNS) produces neuroplasticity to orchestrate adaptive defensive behaviors. This article integrates affective neuroscience, psychopharmacology, neuroanatomy and molecular biology data. In addition, there are two problems with current MDD treatments, namely: 1) Low rates of responsiveness to antidepressants and too slow onset of therapeutic effect; 2) Increased stress vulnerability and autonomy, which reduces the responses of currently available treatments. In the present review, we encourage the prospection of new bioactive agents for the development of treatments with post-transduction mechanisms, neurogenesis and pharmacogenetics inducers that bring greater benefits, with reduced risks and maximized access to patients, stimulating the field of research on mood disorders in order to use the potential of preclinical studies. For this purpose, improved animal models that incorporate the molecular and anatomical tools currently available can be applied. Besides, we encourage the study of drugs that do not present "classical application" as antidepressants, (e.g., the dissociative anesthetic ketamine and dextromethorphan) and drugs that have dual action mechanisms since they represent potential targets for novel drug development more useful for the treatment of MDD.

TIGIT and PD-1 dual checkpoint blockade enhances antitumor immunity and survival in GBM

The use of inhibitory checkpoint blockade in the management of glioblastoma has been studied in both preclinical and clinical settings. TIGIT is a novel checkpoint inhibitor recently discovered to play a role in cancer immunity. In this study, we sought to determine the effect of anti-PD-1 and anti-TIGIT combination therapy on survival in a murine glioblastoma (GBM) model, and to elucidate the underlying immune mechanisms. Using mice with intracranial GL261-luc⁺ tumors, we found that TIGIT expression was upregulated on CD8⁺ and regulatory T cells (Tregs) in the brain compared to draining cervical lymph nodes (CLN) and spleen. We then demonstrated that treatment using anti-PD-1 and anti-TIGIT dual therapy significantly improved survival compared to control and monotherapy groups. The therapeutic effect was correlated with both increased effector T cell function and downregulation of suppressive Tregs and tumor-infiltrating dendritic cells (TIDCs). Clinically, TIGIT expression on tumor-infiltrating lymphocytes was shown to be elevated in patient GBM samples, suggesting that the TIGIT pathway may be a valuable therapeutic target. Expression of the TIGIT ligand, PVR, further portended a poor survival outcome in patients with low-grade glioma. We conclude that anti-TIGIT is an effective treatment strategy against murine GBM when used in combination with anti-PD-1, improving overall survival via modifications of both the T cell and myeloid compartments. Given evidence of PVR expression on human GBM cells, TIGIT presents as a promising immune therapeutic target in the management of these patients.

Adipose stromal vascular fraction attenuates TH1 cell-mediated pathology in a model of multiple sclerosis

Background

The therapeutic efficacy of adipose-derived stem cells (ASCs) has been investigated for numerous clinical indications, including autoimmune and neurodegenerative diseases. Less is known using the crude adipose product called stromal vascular fraction (SVF) as therapy, although our previous studies demonstrated greater efficacy at late-stage disease compared to ASCs in the experimental autoimmune encephalomyelitis (EAE) mouse, a model of multiple sclerosis. In this study, SVF cells and ASCs were administered during the pathogenic progression, designated as early disease, to elucidate immunomodulatory mechanisms when high immune cell activities associated with autoimmune signaling occur. These implications are essential for clinical translation when considering timing of administration for cell therapies.

Methods

We investigated the effects of SVF cells and ASCs by analyzing the spleens, peripheral blood, and central nervous system tissues throughout the course of EAE disease following administration of SVF cells, ASCs, or vehicle. In vitro, immunomodulatory potentials of SVF cells and ASCs were measured when exposed to EAE-derived splenocytes.

Results

Interestingly, treatment with SVF cells and ASCs transiently enhanced the severity of disease directly after administration, substantiating this critical immunomodulatory signaling. More importantly, it was only the EAE mice treated with SVF cells that were able to overcome the advancing pathogenesis and showed improvements by the end of the study. The frequency of lesions in spinal cords following SVF treatment correlated with diminished activities of the T helper type 1 cells, known effector cells of this disease. Co-cultures with splenocytes isolated from EAE mice revealed transcripts of interleukin-10 and transforming growth factor-β, known promoters of regulatory T cells, that were greatly expressed in SVF cells compared to ASCs, and expression levels of signaling mediators related to effector T cells were insignificant in both SVF cells and ASCs.

Conclusion

This is the first evidence, to date, to elucidate a mechanism of action of SVF treatment in an inflammatory, autoimmune disease. Our data supports key immunomodulatory signaling between cell therapies and T cells in this T cell-mediated disease. Together, treatment with SVF mediated immunomodulatory effects that diminished effector cell activities, promoted regulatory T cells, and reduced neuroinflammation.

Therapeutic reduction of cell-mediated immunosuppression in mycosis fungoides and Sézary syndrome

Tumor progression is associated with progressive immunosuppression mediated in part by T regulatory cell(s) (Treg) and/or myeloid-derived suppressor cell(s) (MDSC). Development of strategies to reduce populations of immune cells with suppressive function in cancer patients may enable the induction or recovery of immunity against tumor cells, which may limit or reverse disease progression. With a goal of developing Treg and MDSC neutralizing strategies to treat mycosis fungoides (MF) and Sézary syndrome (SzS), we determined the association between disease stage and suppressor cell populations in patients with MF/SzS, including those responding to therapy. We found elevations in Treg populations, across Treg subtypes, in patients with SzS, and these Treg markedly suppressed proliferation of autologous CD4+CD25- responder T cells. Interestingly, while MDSC numbers were not increased in MF/SzS patients, MDSC from patients with stage IB and above produced significantly more reactive oxygen species than those from stage IA MF patients and control cohorts. Therapy with the CD25-targeting agent denileukin diftitox or IFN-α2b was associated with a reduction in Treg numbers or MDSC function, respectively. These studies identify potential mechanisms of action for these therapies and support the development of coordinated strategies targeting both Treg and MDSC activities in patients with MF/SzS.

The role of regulatory T cells in immunopathogenesis and immunotherapy of viral infections

Two hepatotropic viruses hepatitis C virus (HCV) and hepatitis B virus (HBV) have been considered as the main cause of chronic viral infections. In addition, human immunodeficiency virus (HIV) attacks the immune system by eradication of some white blood cell (T-helper cell). The role of Tregs in HCV, HBV and HIV infections ranges from suppressing antiviral T cell responses to protecting tissues as liver and immune cells from immune mediated injury. In this review, we discuss the influence of regulatory T cells in immunopathology of specific viral infections including HCV, HBV and HIV by focusing on targeting Tregs as novel approach in vaccinology against viral infections.

Immune evasion mechanisms and immune checkpoint inhibition in advanced merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare skin cancer caused by Merkel cell polyomavirus (MCPyV) infection and/or ultraviolet radiation-induced somatic mutations. The presence of tumor-infiltrating lymphocytes is evidence that an active immune response to MCPyV and tumor-associated neoantigens occurs in some patients. However, inhibitory immune molecules, including programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1), within the MCC tumor microenvironment aid in tumor evasion of T-cell-mediated clearance. Unlike chemotherapy, treatment with anti-PD-L1 (avelumab) or anti-PD-1 (pembrolizumab) antibodies leads to durable responses in MCC, in both virus-positive and virus-negative tumors. As many tumors are established through the evasion of infiltrating immune-cell clearance, the lessons learned in MCC may be broadly relevant to many cancers.

Seminal Fluid-Mediated Inflammation in Physiology and Pathology of the Female Reproductive Tract

Inflammation is a multifaceted process involving a host of resident and recruited immune cells that eliminate the insult or injury and initiate tissue repair. In the female reproductive tract (FMRT), inflammation-mediated alterations in epithelial, vascular, and immune functions are important components of complex physiological processes and many local and systemic pathologies. It is well established that intracoital and postcoital function of seminal fluid (SF) goes beyond nutritive support for the spermatozoa cells. SF, in particular, the inflammatory bioactive lipids, and prostaglandins present in vast quantities in SF, have a role in localized immune modulation and regulation of pathways that can exacerbate inflammation in the FMRT. In sexually active women SF-mediated inflammation has been implicated in physiologic processes such as ovulation, implantation, and parturition while also enhancing tumorigenesis and susceptibility to infection. This review highlights the molecular mechanism by which SF regulates inflammatory pathways in the FMRT and how alterations in these pathways contribute to physiology and pathology of the female reproductive function. In addition, based on findings from TaqMan® 96-Well Plate Arrays, on neoplastic cervical cells treated with SF, we discuss new findings on the role of SF as a potent driver of inflammatory and tumorigenic pathways in the cervix.

Regulatory T Cells: Molecular Actions on Effector Cells in Immune Regulation

T regulatory cells play a key role in the control of the immune response, both in health and during illness. While the mechanisms through which T regulatory cells exert their function have been extensively described, their molecular effects on effector cells have received little attention. Thus, this revision is aimed at summarizing our current knowledge on those regulation mechanisms on the target cells from a molecular perspective.

Increased percentages of regulatory T cells are associated with inflammatory and neuroendocrine responses to acute psychological stress and poorer health status in older men and women

RATIONALE

The percentage of regulatory T cells (TRegs)-a subtype of T lymphocyte that suppresses the immune response-appears to be reduced in a number of stress-related diseases. The role of the TReg in stress-disease pathways has not yet been investigated.

OBJECTIVES

The aim of the study was to investigate the association between biological responsivity to acute psychosocial stress and the percentage of TRegs in healthy older adults. The secondary purpose was to measure the associations between TReg percentage and psychological and physical well-being in the participants.

METHODS

Salivary cortisol and plasma interleukin (IL)-6 samples were obtained from 121 healthy older men and women from the Whitehall II cohort following acute psychophysiological stress testing. Three years later at a follow-up visit, we measured TReg percentages and psychological and physical well-being were recorded using the Short Form 36 Health Survey and the Center for Epidemiologic Studies Depression Scale.

RESULTS

Blunted cortisol responses (p = 0.004) and elevated IL-6 responses (p = 0.027) to acute psychophysiological stress were associated with greater TReg percentage independently of age, sex, BMI, smoking status, employment grade, time of testing, and baseline measures of cortisol and IL-6, respectively. Percentage of TRegs was associated cross-sectionally with lower physical (p = 0.043) and mental health status (p = 0.008), and higher levels of depressive symptoms (p = 0.002), independently of covariates.

CONCLUSIONS

Increased levels of TRegs may act as a defence against increased inflammation and may be a pre-indication for chronically stressed individuals on the cusp of clinical illness.

Accumulation of Regulatory T Cells and Chronic Inflammation in the Middle Ear in a Mouse Model of Chronic Otitis Media with Effusion Induced by Combined Eustachian Tube Blockage and Nontypeable Haemophilus influenzae Infection

Nontypeable Haemophilus influenzae (NTHi) is associated with chronic otitis media (COM). In this study, we generated a murine model of COM by using eustachian tube (ET) obstruction and NTHi (10(7) CFU) inoculation into the tympanic bulla, and we investigated the relationship between regulatory T cells (Treg) and chronic inflammation in the middle ear. Middle ear effusions (MEEs) and middle ear mucosae (MEM) were collected at days 3 and 14 and at 1 and 2 months after inoculation. Untreated mice served as controls. MEEs were used for bacterial counts and to measure the concentrations of cytokines. MEM were collected for histological evaluation and flow cytometric analysis. Inflammation of the MEM was prolonged throughout this study, and the incidence of NTHi culture-positive MEE was 38% at 2 months after inoculation. The levels of interleukin-1β (IL-β), tumor necrosis factor alpha, IL-10, and transforming growth factor β were increased in the middle ear for up to 2 months after inoculation. CD4(+) CD25(+) FoxP3(+) Treg accumulated in the middle ear, and the percentage of Treg in the MEM increased for up to 2 months after inoculation. Treg depletion induced a 99.9% reduction of bacterial counts in MEEs and also significantly reduced the ratio of NTHi culture-positive MEE. The levels of these cytokines were also reduced in MEEs. In summary, we developed a murine model of COM, and our findings indicate that Treg confer infectious tolerance to NTHi in the middle ear.

Role of regulatory T cell in clinical outcome of traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a life-threatening disease worldwide. Regulatory T cells (Treg cells) were involved in the immunological system in central nervous system. It is defined as a subpopulation of CD4 + cells that express CD25 and transcription factor forkhead box P3. The level of circulating Treg cells increases in a variety of pathologic conditions. The purpose of this study was to uncover the role of circulating Treg cells in TBI.

METHODS

A clinical study was conducted in two neurosurgical intensive care units of Tianjin Medical University General Hospital and Second Hospital of Tianjin Medical University (Tianjin, China). Forty patients and 30 healthy controls were recruited from August 2013 to November 2013. Circulating Treg cells was detected on the follow-up period of 1, 4, 7, 14, and 21 days after TBI. Blood sample (1 ml) was withdrawn in the morning and processed within 2 h.

RESULTS

There was no significant difference in the level of circulating Treg cells between TBI patients and normal controls during follow-up. TBI patients exhibited higher circulating Treg level than normal controls on the 1 st day after TBI. Treg level was decreased on the 4 th day, climbed up on the 7 th day and peaked on 14 th day after TBI. Treg cells declined to the normal level on 21 th day after TBI. The level of circulating Treg cells was significantly higher in survival TBI patients when compared to nonsurvival TBI patients. TBI patients with improved conditions exhibited significantly higher circulating Treg level when compared to those with deteriorated conditions. The circulating Treg level was correlated with neurologic recovery after TBI. A better neural recovery and lower hospital mortality were found in TBI patients with circulating Treg cells more than 4.91% in total CD4 + mononuclear cells as compared to those with circulating Treg cells less than 4.91% in total CD4 + mononuclear cells in the first 14 days.

CONCLUSIONS

The level of circulating Treg cells is positively correlated with clinical outcome of TBI. The level of Treg cells predicts the progress for TBI patients and may be a target in TBI treatment.

FOXP3(+) Treg Cells and Gender Bias in Autoimmune Diseases

CD4⁺CD25⁺ regulatory T (Treg) cells play a pivotal role in the maintenance of immune homeostasis, where the X-linked master transcription factor forkhead box P3 (FOXP3) determines Treg cell development and function. Genetic deficiency of foxp3 induces dysfunction of Treg cells and immuno-dysregulation, polyendocrinopathy, enteropathy, and X-linked syndrome in humans. Functionally deficient Treg cells or the development of exTreg cells positively correlate with autoimmune diseases, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), and ankylosing spondylitis (AS). In general, females are more susceptible to SLE and MS but less susceptible to AS, where the expression of FOXP3 and its protein complex are perturbed by multiple factors, including hormonal fluctuations, inflammatory cytokines, and danger signals. Therefore, it is critical to explore the potential molecular mechanisms involved and these differences linked to gender. Here, we review recent findings on the regulation of FOXP3 activity in Treg cells and also discuss gender difference in the determination of Treg cell function in autoimmune diseases.

The Macrophage Galactose-Type C-Type Lectin (MGL) Modulates Regulatory T Cell Functions

Regulatory T cells (Tregs) are physiologically designed to prevent autoimmune disease and maintain self-tolerance. In tumour microenvironments, their presence is related to a poor prognosis, and they influence the therapeutic outcome due to their capacity to suppress the immune response by cell-cell contact and to release immunosuppressive cytokines. In this study, we demonstrate that Treg immunosuppressive activity can be modulated by the cross-linking between the CD45RA expressed by Tregs and the C-type lectin MGL. This specific interaction strongly decreases the immunosuppressive activity of Tregs, restoring the proliferative capacity of co-cultured T lymphocytes. This effect can be attributed to changes in CD45RA and TCR signalling through the inhibition of Lck and inactivation of Zap-70, an increase in the Foxp3 methylation status and, ultimately, the reduced production of suppressive cytokines. These results indicate a role of MGL as an immunomodulator within the tumour microenvironment interfering with Treg functions, suggesting its possible use in the design of anticancer vaccines.

Natural Killer Cell Immunotherapy: From Bench to Bedside

The potential of natural killer (NK) cells to target numerous malignancies in vitro has been well documented; however, only limited success has been seen in the clinic. Although NK cells prove non-toxic and safe regardless of the cell numbers injected, there is often little persistence and expansion observed in a patient, which is vital for mounting an effective cellular response. NK cells can be isolated directly from peripheral blood, umbilical cord blood, or bone marrow, expanded in vitro using cytokines or differentiated in vitro from hematopoietic stem cells. Drugs that support NK cell function such as lenalidomide and bortezomib have also been studied in the clinic, however, the optimum combination, which can vary among different malignancies, is yet to be identified. NK cell proliferation, persistence, and function can further be improved by various activation techniques such as priming and cytokine addition though whether stimulation pre- or post-injection is more favorable is another obstacle to be tackled. Here, we review the various methods of obtaining and activating NK cells for use in the clinic while considering the ideal product and drug complement for the most successful cellular therapy.