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T Cell Regulation by the Environment

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197330 Year: Pages: 115 DOI: 10.3389/978-2-88919-733-0 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-04-07 11:22:02
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Naïve T cells get activated upon encounter with their cognate antigen and differentiate into a specific subset of effector cells. These T cells are themselves plastic and are able to re-differentiate into another subset, changing both phenotype and function. Differentiation into a specific subset depends on the nature of the antigen and of the environmental milieu. Notably, certain nutrients, such as vitamins A and D, sodium chloride, have been shown to modulate T cell responses and influence T cell differentiation. Parasite infection can also skew Th differentiation. Similarly, the gut microbiota regulates the development of immune responses. Lastly, the key role of metabolism on T cells has also been demonstrated. This series of articles highlights some of the multiple links existing between environmental factors and T cell responses.

Investigating and harnessing T-cell functions with engineered immune receptors and their ligands

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194131 Year: Pages: 191 DOI: 10.3389/978-2-88919-413-1 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2015-12-10 11:59:06
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T-cells are an essential component of the immune system that provide protection against pathogen infections and cancer and are involved in the aetiology of numerous autoimmune and autoinflammatory pathologies. Their importance in disease, the relative ease to isolate, expand and manipulate them ex vivo have put T-cells at the forefront of basic and translational research in immunology. Decades of study have shed some light on the unique way T-cells integrate extrinsic environmental cues influencing an activation program triggered by interactions between peptide-MHC complexes and the antigen-recognition machinery constituted of clonally distributed T-cell receptors and their co-receptor CD4 or CD8. The manipulation of these molecular determinants in cellular systems or as recombinant proteins has considerably enhanced our ability to understand antigen-specific T-cell activation, to monitor ongoing T-cell responses and to exploit T-cells for therapy. Even though these principles have given numerous insights in the biology of CD8+ T-cells that translate into promising therapeutic prospects, as illustrated by recent breakthroughs in cancer therapy, they have proven more challenging to apply to CD4+ T-cells.This Research Topics aims to provide a comprehensive view of the recent insights provided by the use of engineered antigen receptors and their ligands on T-cell activation and how they have been or could be harnessed to design efficient immunotherapies.

Glial Cells: Managers of Neuro-immunity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198351 Year: Pages: 224 DOI: 10.3389/978-2-88919-835-1 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
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Immune responses within the brain are still scarcely explored. Nerve tissue damage is accompanied by the activation of glial cells, primarily microglia and astroglia, and such activation is responsible for the release of cytokines and chemokines that maintain the local inflammatory response and actively recruit lymphocytes and monocytes to the damaged areas. Theoretically, these responses are designed to repair the brain damage. However, alterations, or a chronic perpetuation of these responses may underlie a number of neuro-pathologies. It is thought that each inflammatory scenario within the brain have a specific biochemical footprint characterized by the release of determined cytokines, chemokines and growing factors able to define particular immunological responses. Alongside, glial cells transform their cell body, become larger and develop higher number of branches adopting an active morphological phenotype. These changes are related with the search of interactions with other cells, such as bystander resident cells of the brain parenchyma, but also cells homing from the blood stream. In this process, microglia and astrocytes communicates with other cells by the formation of specific intercellular connections that are still poorly understood. These interactions are complex and entail the arrangement of cytoskeletal compounds, secretory and phagocytic domains. In this particular crosstalk there is a two-way communication in which glial cells and target cells come together establishing interfaces with specific information exchange. This way, glial cells orchestrate the particular response recruiting cellular subsets within the central nervous system and organizing the resolution of the brain damage. In this Frontiers Research Topic, we compile a selection of articles unfolding diverse aspects of glial-derived inflammation, focused on neurodegenerative diseases and other nervous system disorders, with special emphasis on microglia/macrophages as leading actors managing neuro-immunity.

Dendritic Cell Control of Immune Responses

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198689 Year: Pages: 121 DOI: 10.3389/978-2-88919-868-9 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-01-19 14:05:46
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Dendritic cells (DC) are among the first cells to encounter pathogens and damage in peripheral tissues and, upon activation, DC migrate to lymph nodes where they activate and educate T cells to initiate and shape the immune response. DC present pathogen-derived antigen to T cells and drive T cell differentiation into particular effector cells through the expression and secretion of co-stimulatory molecules and cytokines respectively. The study of DC biology has included the identification of multiple DC subsets in tissues and lymphoid organs, the differentiation and plasticity of DC subsets, the functional consequences of DC interaction with pathogen, control of DC migratory properties and the impact of DC on T cell activation and differentiation. In recent years sophisticated systems biology approaches have been developed to deepen our understanding of DC function. These studies have identified differences between DC subsets located in various tissues and critical factors that drive the outcome of the interaction between DC and T cells. DC are currently being used in in various clinical therapeutic settings, including as vaccines for cancer and autoimmune disease. A clear understanding of DC factors that contribute to specific immune responses is vital to the success of DC based therapies. This research topic will give a comprehensive overview of current issues in DC biology and provides an update on the clinical uses of DC in the therapy of autoimmunity and cancer.

The immunology of cellular stress proteins

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193257 Year: Pages: 89 DOI: 10.3389/978-2-88919-325-7 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-03-10 08:14:32
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Stress proteins or heat-shock proteins (HSP) are evolutionary conserved proteins present in every prokaryotic and eukaryotic cell. Their main function is to protect cells and proteins from damage under stressful circumstances. The latter circumstances do include the cell and protein damaging effects of inflammation. The discovery of mycobacterial HSP60 being a critical antigen in the model of adjuvant arthritis, has led to studies that showed the immuno-dominance of microbial HSP60 and the potential of the microbial HSP induced repertoire of antibodies and T cells to cross-recognize the self-HSP homologues of stressed cells. Since then, the research in the immunology of stress proteins started to comprise a widening spectrum of topics with potential medical relevance. Interestingly, since stress proteins have their activities in both innate and adaptive immunity, they are key elements in the cross-roads between both arms of the immune system. Stress proteins or HSP can be considered as functional 'biomarkers' of inflammation. They are up-regulated locally during inflammation and interestingly, they seem to function as targets for anti-inflammatory regulatory T cells. In experimental models of autoimmunity, mainly arthritis, administration of HSP peptides have been shown to suppress disease. First clinical trials have shown the anti-inflammatory nature of T cell responses to Hsp. In type I diabetes and in rheumatoid arthritis, parenteral and oral administration of Hsp peptides were shown to induce a bias in pro-inflammatory T cells, switching them in the direction of regulatory cytokine production (IL4, IL5 and IL10). In addition a raised level of a marker of natural T regulatory cells, the transcription factor FoxP3, was noted in the RA trial. Other inflammatory diseases or diseases with inflammatory components which feature the immune imprint of the up-regulated Hsp are atherosclerosis, inflammatory bowel diseases, multiple sclerosis and atopic diseases such atopic dermatitis and allergic asthma.

Protective Immune Response to Dengue Virus Infection and Vaccines: perspectives from the field to the bench

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195114 Year: Pages: 97 DOI: 10.3389/978-2-88919-511-4 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2015-12-03 13:02:24
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Dengue is the most important mosquito-transmitted viral disease in humans. Half of the world population is at risk of infection, mostly in tropical and sub-tropical areas. The World Health Organization (WHO) estimates that 50 to 100 million infections occur yearly, with 50,000 to 100,000 deaths related to dengue, mainly in children. Recent estimates show higher numbers, up to three times more, with 390 million estimated dengue infections per year, among which 96 million apparent infections (Bhatt et al. 2013). Initially localized to South-East Asia, dengue virus (DENV) started its spread in Latin America in the 80s. Little is known about DENV spread in Africa, but multiple seroprevalence surveys over several years are now clearly showing endemic areas in East and West Africa (Brady et al. 2013). Finally, due to global warming and intense traveling there is a risk of global spread towards more temperate regions, and both US Key islands (FL) and southern Europe recently faced DENV outbreaks. There are currently no specific treatments or vaccines available. Even though several dengue vaccines are in the pipeline, clear correlates of protection are still lacking. The recent failure of the live-attenuated Sanofi vaccine Phase 2b trial (Sabchareon et al. 2013) and the lack of correlation between clinical protection and in vitro neutralization assays, clearly underlines the necessity to better understand the role of the different components of the immune system in protection against dengue virus infection and the requirement for the development of additional and/or improved predictive assays. The aim of this research topic is to provide novel data, opinions and literature reviews on the best immune correlates of protection and recent advances in the immune response to DENV infection that can allow rapid progress of dengue vaccines. Authors can choose to submit original research papers, reviews or opinions on pre-clinical or clinical observations that will help unify the field, with perspectives from epidemiology, virology, immunology and vaccine developers. This research topic will discuss different aspects of the protective immune response to DENV that can influence vaccine development. It will include a review of epidemiological data generated in the field, which will address spatio-temporal diversity of DENV epidemics, the importance of cross-reactive protection and of the time-interval between infections as a predictor of disease. It will further include a review of the role of both the innate and adaptive immunity in DENV infection control, and discuss the usefulness of new improved animal models in dissecting the role of each immunological compartment, which will help define new correlate of immune protection. New data concerning the DENV structure and anti-dengue antibody structure will address the necessity of improved neutralization assays. The ultimate test to prove vaccine efficacy and study immune correlates of protection in humans before large trials will open up the discussion on human DENV challenges using controlled attenuated viral strains. Finally, the role of vaccines, administered in flavi-immune populations, in the modification of future epidemics will also be approached and will include novel studies on mosquitoes infection thresholds.

CD1- and MR1-restricted T Cells in Antimicrobial Immunity

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889197507 Year: Pages: 189 DOI: 10.3389/978-2-88919-750-7 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2016-04-07 11:22:02
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Cell-mediated immunity to extracellular and intracellular microbes has been traditionally linked to CD4+ and CD8+ T cells that recognize pathogen-derived peptides in the context of major histocompatibility complex (MHC) class II and class I molecules, respectively. Recent progress in our understanding of early host defense mechanisms has brought ‘unconventional’, innate-like T cells into the spotlight. These are a heterogeneous population of non-MHC-restricted T cells that exhibit ‘memory-like’ properties and mount emergency responses to infection. They may directly detect and destroy infected cells, but are best known for their ability to regulate downstream effector cells including but not limited to conventional T cells. Innate-like T cells include among others CD1-restricted natural killer T (NKT) cells and MR1-restricted mucosa-associated invariant T (MAIT) cells. NKT cells recognize lipid antigens, and MAIT cells were recently demonstrated to respond to microbe-derived vitamin B metabolites. However, much remains to be learned about the antigen specificity range of these cells, their activation mode and their true potentials in immunotherapeutic applications. Like in many other areas of biology, uncertainties and controversies surrounding these cells and some of the experimental models, techniques and reagents employed to study them have brought about excitement and sometimes hot debates. This Special Topic was launched to provide updated reviews on protective and/or pathogenic roles of NKT and MAIT cells during infection. Leading experts discuss current controversies, pressing questions and the challenges that lie ahead for the advancement of this intriguing and rapidly evolving area of immunology. Unlike MHC, CD1 and MR1 display very limited polymorphism. Therefore, NKT and MAIT cells may be considered attractive targets for various diseases in diverse human populations. The potential benefits of NKT cell- and MAIT cell-based vaccination and treatment strategies in infectious diseases is an important subject that is also covered in this Topic.

Bone Marrow T Cells at the Center Stage in Immunological Memory

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450930 Year: Pages: 84 DOI: 10.3389/978-2-88945-093-0 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2017-07-06 13:27:36
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Increasing evidence supports the notion that bone marrow (BM) represents a relevant player in T cell responses, particularly in its role as a specialized organ for long-term memory. Memory T cells are enriched in the BM over long times after priming, and can be recruited to the periphery upon antigenic challenge. The articles in this research topic include discussions of whether these T cells are passing-through or truly resident, as well as a debate on the extent of proliferation of BM memory T cells. Original research articles in this collection include an analysis of the number of memory T cells found in different bones as well as effects of B cell depletion on T cell memory in the BM. T cells in the BM can influence a number of processes, from bone remodeling, control of cancer, to effects on hemopoiesis or Graft versus Host Disease (GVHD). This research topic contains several contributions to these topics including discussions on how to translate BM T cell knowledge into medicine.

Understanding Crohn's Disease: Immunity, Genes and Microbes

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452149 Year: Pages: 126 DOI: 10.3389/978-2-88945-214-9 Language: English
Publisher: Frontiers Media SA
Subject: Allergy and Immunology --- Medicine (General)
Added to DOAB on : 2017-10-13 14:57:01
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Crohn's disease (CD) is a chronic, relapsing, inflammatory bowel disease resulting in considerable morbidity and reduced quality of life. Although still under intense debate, CD seems to result from an enhanced and uncontrolled immune response to the gut microbiota. CD is thought to be multifactorial depending on genetic and environmental determinants. In recent years, nearly 100 single nucleotide polymorphisms (SNPs) were associated with increased risk of developing CD (some of the SNPs also associated with susceptibility to ulcerative colitis, another type of IBD). These SNPs are mostly located in genes involved in innate and adaptive immunity mechanisms, such as autophagy, expression of pattern-recognition receptors and citokine signaling. Epigenetics is also probably playing a role in CD susceptibility, as it is sensitive to environmental conditions and may mediate gene-environment interactions. Environmental factors possibly involved in CD development include diet, gut microbiota composition and infection with specific pathogens, of which the most consistently associated to CD are Mycobacterium avium subsp. paratuberculosis and adherent-invasive Escherichia coli. This Topic aimed at bringing together contributions covering different genetic, epigenetic, immunological and microbial processes involved in the development of CD, helping to drive forward the understanding of CD immunopahtology.

Diacylglycerol Kinase Signalling

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453351 Year: Pages: 96 DOI: 10.3389/978-2-88945-335-1 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Biology
Added to DOAB on : 2018-02-27 16:16:45
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Diacylglycerol kinases (DGKs) phosphorylate diacylglycerol (DG), catalyzing its conversion into phosphatidic acid (PA). This reaction attenuates membrane DG levels, limiting the localization/activation of signaling proteins that bind this lipid. Initially recognized as modulators of classical and novel PKC family members, the function of the DGK has further expanded with the identification of novel DG effectors including Ras Guanyl nucleotide-releasing proteins (RasGRP) and chimaerin Rac GTPases. The product of the DGK reaction, PA, is also a signaling lipid that mediates activation of multiple proteins including the mammalian target of rapamycin (mTOR). The DGK pathway thus modulates two lipids with important signaling properties that are also key intermediates in lipid metabolism and membrane trafficking. The DGK family in eukaryotes comprises 10 different members grouped into five different subfamilies characterized by the presence of particular regulatory motifs. These regions allow the different DGK isoforms to establish specific complexes and/or to be recruited to specific subcellular compartments. The subtle regulation of DG and PA catalyzed byspecific DGKs is sensed by a restricted set of molecules, providing the means for spatio-temporal regulation of signals in highly specialized cell systems.In the recent years, multiple studies have unveiled the functions of specific isoforms, their mechanisms of regulation and their participation in different pathways leading to and from DG and PA. Animal models have greatly helped to understand the specialized contribution of DGK mediated signals, particularly in the immune and central nervous systems. Mice deficient for individual DGK isoforms show defects in T and B cell functions, dendritic spine maintenance, osteoclast and mechanical-induced skeletal muscle formation. Studies in flies and worms link DGK mediated DAG metabolism with mTOR- mediated regulation of lifespan and stress responses. In plants DGK mediated PA formation contributes to plant responses to environmental signals.Aberrant DGK function has been recently associated with pathological states, an expected consequence of the essential role of these enzymes in the regulation of multiple tissue and systemic functions. DGK mutations/deletions have been related to human diseases including diabetes, atypical hemolytic-uremic syndrome, Parkinson disease and bipolar disorders. On the contrary DGK upregulation emerges as a non-oncogenic addition of certain tumors and represents one of the main mechanism by which cancer evades the immune attack. As a result, the DGK field emerges an exciting new area of research with important therapeutic potential.

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