scholarly journals Coinhibitory Molecules in Autoimmune Diseases

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Norihiko Watanabe ◽  
Hiroshi Nakajima
Keyword(s):  
T Cells ◽  
Animal Models ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Clinical Investigation ◽  
Great Promise ◽  
Self Antigens

Coinhibitory molecules such as CTLA-4, PD-1 and BTLA negatively regulate immune responses. Multiple studies indicate that the deficiency or mutation of coinhibitory molecules leads to the development of autoimmune diseases in mice and humans, indicating that the negative signals from coinhibitory molecules are crucial for the prevention of autoimmunity. In some conditions, the administration of decoy coinhibitory receptors (e.g., CTLA-4 Ig) or mAb against coinhibitory molecules suppresses the responses of self-reactive T cells in autoimmune diseases. Therefore, modulation of coinhibitory signals seems to be an attractive approach to induce tolerance in autoimmune diseases in humans where the disease-inducing self-antigens are not known. Particularly, administration of CTLA-4 Ig has shown great promise in animal models of autoimmune diseases and has been gaining increasing attention in clinical investigation in several autoimmune diseases in humans.

scholarly journals The Complex Role of Regulatory T Cells in Immunity and Aging

2021 ◽  
Vol 11 ◽  
Author(s):  
Lourdes Rocamora-Reverte ◽  
Franz Leonard Melzer ◽  
Reinhard Würzner ◽  
Birgit Weinberger
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Immune Cells ◽  
Treg Cells ◽  
T Cell Subsets ◽  
Γδt Cells ◽  
Cell Functions ◽  
Age Related ◽  
Self Antigens

The immune system is a tightly regulated network which allows the development of defense mechanisms against foreign antigens and tolerance toward self-antigens. Regulatory T cells (Treg) contribute to immune homeostasis by maintaining unresponsiveness to self-antigens and suppressing exaggerated immune responses. Dysregulation of any of these processes can lead to serious consequences. Classically, Treg cell functions have been described in CD4+ T cells, but other immune cells also harbour the capacity to modulate immune responses. Regulatory functions have been described for different CD8+ T cell subsets, as well as other T cells such as γδT cells or NKT cells. In this review we describe the diverse populations of Treg cells and their role in different scenarios. Special attention is paid to the aging process, which is characterized by an altered composition of immune cells. Treg cells can contribute to the development of various age-related diseases but they are poorly characterized in aged individuals. The huge diversity of cells that display immune modulatory functions and the lack of universal markers to identify Treg make the expanding field of Treg research complex and challenging. There are still many open questions that need to be answered to solve the enigma of regulatory T cells.

scholarly journals Comparative transcriptome analysis reveals distinct genetic modules associated with Helios expression in intratumoral regulatory T cells

2018 ◽  
Vol 115 (9) ◽  
pp. 2162-2167 ◽  
Author(s):  
Kathleen Yates ◽  
Kevin Bi ◽  
W. Nicholas Haining ◽  
Harvey Cantor ◽  
Hye-Jung Kim
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Genetic Basis ◽  
Cell Function ◽  
Receptor Expression ◽  
Central Feature ◽  
Costimulatory Receptor ◽  
Th Cell ◽  
Self Antigens

Regulatory T cells (Tregs) are key modulators of immune tolerance, capable of suppressing inflammatory immune responses and promoting nonlymphoid tissue homeostasis. Helios, a transcription factor (TF) that is selectively expressed by Tregs, has been shown to be essential for the maintenance of Treg lineage stability in the face of inflammatory conditions that include autoimmune disease and cancer. Helios-deficient Tregs within tumors acquire effector T cell function and contribute to immune responses against cancer. However, the underlying genetic basis of this Treg reprogramming is not well understood. Here, we report that Helios-deficient Tregs within the chronic inflammatory tumor microenvironment (TME) derepress genetic programs associated with T helper (Th) cell differentiation by up-regulating Th cell-associated TFs and effector cytokines. These genetic changes of Helios-deficient Tregs are most apparent in a Treg subpopulation with high affinity for self-antigens, as detected by both increased GITR/PD-1 expression and increased responsiveness to self-antigens. Their combined effects may promote a phenotype conversion of Tregs into effector T cells within the TME, where TCR engagement and costimulatory receptor expression by Tregs are increased. These data provide a genetic basis for the unstable phenotype of Helios-deficient Tregs within the inflammatory environment of tumors and suggest that immune milieu-dependent alterations in gene expression are a central feature of Treg conversion.

The role of cytokines in immunological tolerance: potential for therapy

2000 ◽  
Vol 2 (9) ◽  
pp. 1-20 ◽  
Author(s):  
Mark Harber ◽  
Anette Sundstedt ◽  
David Wraith
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Immune System ◽  
Animal Models ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Immunological Tolerance ◽  
Immunomodulatory Effects ◽  
Clinical Potential

Current immunosuppression protocols, although often effective, are nonspecific and therefore hazardous. Consequently, immunological tolerance that is antigen specific and does not globally depress the patient's immune system has become one of the Holy Grails of immunology. Since the discovery that cytokines have immunomodulatory effects, extensive research has investigated the potential of these molecules to induce and maintain specific immunological tolerance in the context of transplantation, allergy and autoimmunity. In this article, we review the possible mechanisms by which cytokines can modulate the immune response and the animal models that frequently confound the theory that a single cytokine, or group of cytokines, can induce tolerance in a predictable manner. Finally, we discuss the role of cytokines at a paracrine level, particularly in the context of inducing and maintaining antigen-specific, regulatory T cells with the clinical potential to suppress specific immune responses.

scholarly journals T Helper 17 Cells in Autoimmune Liver Diseases

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Masanori Abe ◽  
Yoichi Hiasa ◽  
Morikazu Onji
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Th17 Cells ◽  
Transforming Growth Factor ◽  
Treg Cells ◽  
Reciprocal Relationship ◽  
Th2 Cells ◽  
T Helper ◽  
T Helper 17

Many autoimmune diseases are driven by self-reactive T helper (Th) cells. A new population of effector CD4+T cells characterized by the secretion of interleukin (IL)-17, referred to as Th17 cells, has been demonstrated to be phenotypically, functionally, and developmentally distinct from Th1 and Th2 cells. Because the liver is known to be an important source of transforming growth factor-βand IL-6, which are cytokines that are crucial for Th17 differentiation, it is very likely that Th17 cells contribute to liver inflammation and autoimmunity. In contrast, another distinct subset of T cells, regulatory T cells (Treg), downregulate immune responses and play an important role in maintaining self-tolerance. In addition, there is a reciprocal relationship between Th17 cells and Tregs, in development and effector functions, and the balance between Th17 and Treg cells can affect the outcome of immune responses, particularly in autoimmune diseases. In this review, we will focus on the latest investigative findings related to Th17 cells in autoimmune liver disease.

Physiologically high concentrations of 17β-estradiol enhance NF-κB activity in human T cells

2007 ◽  
Vol 292 (4) ◽  
pp. R1465-R1471 ◽  
Author(s):  
Suzue Hirano ◽  
Daisuke Furutama ◽  
Toshiaki Hanafusa
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Intracellular Signaling ◽  
Jurkat Cells ◽  
High Concentration ◽  
Immunoprecipitation Assay ◽  
Human T Cells ◽  
17Β Estradiol

Estrogen has diverse effects on inflammation and immune responses. That pregnancy is associated with remission of some autoimmune diseases and exacerbation of others suggests that physiological fluctuation in estrogen levels could affect the immune responses in humans. However, the molecular basis for these phenomena is poorly understood. We hypothesized that fluctuations of estrogen levels modulate intracellular signaling for immune responses via estrogen receptors (ERs). In reporter assays, 17β-estradiol (E2) at a physiologically high concentration increased the activity of NF-κB in Jurkat cells stimulated by PMA/ionomycin or TNF-α. Overexpression and RNA interference experiments suggested that the effects were mediated through ERβ. Immunoprecipitation assay showed that both ERα and ERβ are directly associated with NF-κB in the cell nucleus. Using chromatin immunoprecipitation assay, we confirmed that ERα and ERβ associated with NF-κB and steroid hormone coactivators at the promoter region of NF-κB regulated gene. Considering that NF-κB regulates the expression of various genes essential for cell growth and death, estrogen could regulate the fate of T cells by affecting the activity of NF-κB. To determine whether E2 alters the fate of T cells, we investigated E2 actions on T cell apoptosis, a well-known NF-κB-mediated phenomenon. E2 increased apoptosis of Jurkat cells and decreased that of human peripheral blood T cells. Our results indicate that E2 at a physiologically high concentration modulates NF-κB signaling in human T cells via ERβ and affects T cell survival, suggesting that these actions may underlie the gender differences in autoimmune diseases.

scholarly journals Liver-Directed AAV8 Booster Vaccine Expressing Plasmodium falciparum Antigen Following Adenovirus Vaccine Priming Elicits Sterile Protection in a Murine Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Mohammad Shahnaij ◽  
Mitsuhiro Iyori ◽  
Hiroaki Mizukami ◽  
Mayu Kajino ◽  
Iroha Yamagoshi ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Malaria Vaccine ◽  
Infected Mosquito ◽  
Great Promise ◽  
Adeno Associated Virus ◽  
Boost Regimen ◽  
Cellular Immune Responses ◽  
Virus Serotype ◽  
Cellular Immune

Hepatocyte infection by malaria sporozoites is a bottleneck in the life-cycle of Plasmodium spp. including P. falciparum, which causes the most lethal form of malaria. Therefore, developing an effective vaccine capable of inducing the strong humoral and cellular immune responses necessary to block the pre-erythrocytic stage has potential to overcome the spatiotemporal hindrances pertaining to parasite biology and hepatic microanatomy. We recently showed that when combined with a human adenovirus type 5 (AdHu5)-priming vaccine, adeno-associated virus serotype 1 (AAV1) is a potent booster malaria vaccine vector capable of inducing strong and long-lasting protective immune responses in a rodent malaria model. Here, we evaluated the protective efficacy of a hepatotropic virus, adeno-associated virus serotype 8 (AAV8), as a booster vector because it can deliver a transgene potently and rapidly to the liver, the organ malaria sporozoites initially infect and multiply in following sporozoite injection by the bite of an infected mosquito. We first generated an AAV8-vectored vaccine expressing P. falciparum circumsporozoite protein (PfCSP). Intravenous (i.v.) administration of AAV8-PfCSP to mice initially primed with AdHu5-PfCSP resulted in a hepatocyte transduction rate ~2.5 times above that seen with intramuscular (i.m.) administration. This immunization regimen provided a better protection rate (100% sterile protection) than that of the i.m. AdHu5-prime/i.m. AAV8-boost regimen (60%, p < 0.05), i.m. AdHu5-prime/i.v. AAV1-boost (78%), or i.m. AdHu5-prime/i.m. AAV1-boost (80%) against challenge with transgenic PfCSP-expressing P. berghei sporozoites. Compared with the i.m. AdHu5-prime/i.v. AAV1-boost regimen, three other regimens induced higher levels of PfCSP-specific humoral immune responses. Importantly, a single i.v. dose of AAV8-PfCSP recruited CD8+ T cells, especially resident memory CD8+ T cells, in the liver. These data suggest that boost with i.v. AAV8-PfCSP can improve humoral and cellular immune responses in BALB/c mice. Therefore, this regimen holds great promise as a next-generation platform for the development of an effective malaria vaccine.

scholarly journals The Generation and Regulation of Tissue-Resident Tregs and Their Role in Autoimmune Diseases

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shuang Wang ◽  
Xueyang Zou ◽  
Yi Zhang ◽  
Xiaoya Wang ◽  
Wei Yang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
T Cells ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Hot Spot ◽  
Exploratory Stage ◽  
And Function

Regulatory T cells (Tregs), as an important subset of T cells, play an important role in maintaining body homeostasis by regulating immune responses and preventing autoimmune diseases. In-depth research finds that Tregs have strong instability and plasticity, and according to their developmental origin, Tregs can be classified into thymic-derived Tregs (tTregs), endogenous-induced Tregs (pTregs), which are produced by antigen-stimulated T cells in the periphery in vivo, and induced Tregs (iTregs), which differentiate from naïve T cells in vitro. In recent years, studies have found that Tregs are divided into lymphatic and tissue-resident Tregs according to their location. Research on the generation and function of lymphoid Tregs has been more comprehensive and thorough, but the role of tissue Tregs is still in the exploratory stage, and it has become a research hot spot. In this review, we discuss the instability and plasticity of Tregs and the latest developments of tissue-resident Tregs in the field of biology, including adipose tissue, colon, skeletal muscle, and other Tregs that have been recently discovered as well as their production, regulation, and function in specific tissues and their role in the pathogenesis of autoimmune diseases.

scholarly journals Imbalance between IL-17A-Producing Cells and Regulatory T Cells during Ischemic Stroke

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yuehua Hu ◽  
Yanhua Zheng ◽  
Ya Wu ◽  
Bing Ni ◽  
Shugui Shi
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Ischemic Stroke ◽  
T Cell ◽  
Animal Models ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
Real Time Pcr ◽  
Treg Cells ◽  
T Cell Subsets

Immune responses and inflammation are key elements in the pathogenesis of ischemic stroke (IS). Although the involvement of IL-17A in IS has been demonstrated using animal models, the involvement of IL-17A and IL-17-secreting T cell subsets in IS patients has not been verified, and whether the balance of Treg/IL-17-secreting T cells is altered in IS patients remains unknown. In the present study, we demonstrated that the proportion of peripheral Tregs and the levels of IL-10 and TGF-βwere reduced in patients with IS compared with controls using flow cytometry (FCM), real-time PCR, and ELISA assays. However, the proportions of Th17 andγδT cells, the primary IL-17A-secreting cells, increased dramatically, and these effects were accompanied by increases in the levels of IL-17A, IL-23, IL-6, and IL-1βin IS patients. These studies suggest that the increase in IL-17A-producing cells and decrease in Treg cells might contribute to the pathogenesis of IS. Manipulating the balance between Tregs and IL-17A-producing cells might be helpful for the treatment of IS.

scholarly journals Vitamin D3and the immune system: maintaining the balance in health and disease

2007 ◽  
Vol 20 (1) ◽  
pp. 106-118 ◽  
Author(s):  
Femke Baeke ◽  
Evelyne Van Etten ◽  
Lut Overbergh ◽  
Chantal Mathieu
Keyword(s):  
Vitamin D ◽  
T Cells ◽  
Immune System ◽  
Animal Models ◽  
Autoimmune Diseases ◽  
Active Form ◽  
Epidemiological Data ◽  
Cell Types ◽  
Dihydroxyvitamin D

1,25-Dihydroxyvitamin D3(1,25(OH)2D3), the active form of vitamin D3, is a central player in Ca and bone metabolism. More recently, important immunomodulatory effects have been attributed to this hormone. By binding to its receptor, the vitamin D receptor, 1,25(OH)2D3regulates the expression of various genes and consequently affects the behaviour of different cell types within the immune system. 1,25(OH)2D3can potently inhibit pathogenic T cells and gives rise to elevated numbers of regulatory T cells via the induction of tolerogenic dendritic cells. These immunomodulatory activities of 1,25(OH)2D3have also been proven usefulin vivo: administration of 1,25(OH)2D3in several animal models can prevent or cure different autoimmune diseases and graft rejection. To overcome the dose-limiting side effects of 1,25(OH)2D3on Ca and bone, less calcaemic structural analogues (alone or in combination with synergistically acting drugs or bone-resorption inhibitors) have been successfully used in animal models. Furthermore, as 1,25(OH)2D3also contributes to host defence against infectious agents by the induction of antimicrobial responses, this molecule might provide a new strategy to deal with drug-resistant infections. According to the pleiotropic effects of 1,25(OH)2D3in the immune system, increasing epidemiological data underline the importance of adequate vitamin D intakes in reducing the risk of several autoimmune diseases and infections such as tuberculosis.

scholarly journals Suppressor T Cells in Human Diseases

2004 ◽  
Vol 200 (3) ◽  
pp. 273-276 ◽  
Author(s):  
Clare Baecher-Allan ◽  
David A. Hafler
Keyword(s):  
T Cells ◽  
Infectious Diseases ◽  
Immune Responses ◽  
Autoimmune Diseases ◽  
Peripheral Tolerance ◽  
Human Diseases ◽  
Suppressor T Cells ◽  
Wide Range ◽  
Human Immune

Although central and peripheral tolerance are important for the regulation of human immune responses to self- and microbial antigens, an important role of suppressor CD4+ CD25+ T cells is suggested from the recent investigations of human autoimmune diseases and HIV. These new data provide increasing evidence that altered function of CD4+ CD25+ T cells may be an important factor in a wide range of human inflammatory and infectious diseases.

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