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self reactive T cell

Nicolle H R Litjens, Lotte van der Wagen, Jurgen Kuball, Jaap Kwekkeboom
Cytomegalovirus (CMV) infection can cause significant complications after transplantation, but recent emerging data suggest that CMV may paradoxically also exert beneficial effects in two specific allogeneic transplant settings. These potential benefits have been underappreciated and are therefore highlighted in this review. First, after allogeneic hematopoietic stem cell transplantation (HSCT) for acute myeloid leukemia (AML) using T-cell and natural killer (NK) cell-replete grafts, CMV reactivation is associated with protection from leukemic relapse...
2018: Frontiers in Immunology
Minghua Zheng, Jie Jiang, Xiao Zhang, Nan Wang, Kaihang Wang, Qiong Li, Tingting Li, Qingshan Lin, Yingbin Wang, Hai Yu, Ying Gu, Jun Zhang, Shaowei Li, Ningshao Xia
Hepatitis E virus (HEV) is associated with acute hepatitis disease. Numerous truncated HEV capsid proteins have been successfully expressed using different expression systems. Among these, p495, a protein truncated at its N- and C-termini by 111 and 54 amino acids (aa), respectively (HEV ORF2 aa 112-606) can self-assemble into T = 1 virus-like particles (VLPs) when expressed by insect cells. A shorter p239 (aa 368-606) protein is a particulate antigen that we have previously used in our commercialized HEV vaccine, Hecolin...
March 12, 2018: Vaccine
Taku Kuwabara, Yukihide Matsui, Fumio Ishikawa, Motonari Kondo
The adaptive immune system involves antigen-specific host defense mechanisms mediated by T and B cells. In particular, CD4⁺ T cells play a central role in the elimination of pathogens. Immunological tolerance in the thymus regulates T lymphocytes to avoid self-components, including induction of cell death in immature T cells expressing the self-reactive T-cell receptor repertoire. In the periphery, mature T cells are also regulated by tolerance, e.g., via induction of anergy or regulatory T cells. Thus, T cells strictly control intrinsic signal transduction to prevent excessive responses or self-reactions...
March 12, 2018: International Journal of Molecular Sciences
Esteban Arrieta-Bolaños, Pietro Crivello, Maximilian Metzing, Thuja Meurer, Müberra Ahci, Julie Rytlewski, Marissa Vignali, Erik Yusko, Peter van Balen, Peter A Horn, J H Frederik Falkenburg, Katharina Fleischhauer
T cell alloreactivity is mediated by a self-human leukocyte antigen (HLA)-restricted T cell receptor (TCR) repertoire able to recognize both structurally similar and dissimilar allogeneic HLA molecules (i.e., differing by a single or several amino acids in their peptide-binding groove). We hypothesized that thymic selection on self-HLA molecules could have an indirect impact on the size and diversity of the alloreactive response. To test this possibility, we used TCR Vβ immunophenotyping and immunosequencing technology in a model of alloreactivity between self-HLA selected T cells and allogeneic HLA-DPB1 (DPB1) differing from self-DPB1*04:02 by a single (DPB1*02:01) or several (DPB1*09:01) amino acids in the peptide-binding groove...
2018: Frontiers in Immunology
Peng Zhang, Qianjin Lu
Immunological tolerance loss is fundamental to the development of autoimmunity; however, the underlying mechanisms remain elusive. Immune tolerance consists of central and peripheral tolerance. Central tolerance, which occurs in the thymus for T cells and bone marrow for B cells, is the primary way that the immune system discriminates self from non-self. Peripheral tolerance, which occurs in tissues and lymph nodes after lymphocyte maturation, controls self-reactive immune cells and prevents over-reactive immune responses to various environment factors...
March 5, 2018: Cellular & Molecular Immunology
Patrícia Lima Falcão, Tarcisio Passos Ribeiro de Campos
Previous studies have demonstrated the expression of the CD25 marker on the surface of naturally occurring T cells (Tregs) of mice, which have a self-reactive cellular profile. Recently, expression of other markers that aid in the identification of these cells has been detected in lymphocyte subtypes of individuals suffering of autoimmune and idiopathic diseases, including: CD25, CTLA-4 (cytotoxic T-lymphocyte antigen 4), HLA-DR (human leukocyte antigen) and Interleukin 10 (IL-10), opening new perspectives for a better understanding of an association between such receptors present on the cell surface and the prognosis of autoimmune diseases...
December 2017: Revista da Associação Médica Brasileira
Kieran D James, William E Jenkinson, Graham Anderson
T-cells bearing the αβTCR play a vital role in defending the host against foreign pathogens and malignant transformation of self. Importantly, T-cells are required to remain tolerant to the host's own cells and tissues in order to prevent self-reactive responses that can lead to autoimmune disease. T-cells achieve the capacity for self/nonself discrimination by undergoing a highly selective and rigorous developmental program during their maturation in the thymus. This organ is unique in its ability to support a program of T-cell development that ensures the establishment of a functionally diverse αβTCR repertoire within the peripheral T-cell pool...
February 27, 2018: Journal of Leukocyte Biology
Julia Seyfarth, Christian Lundtoft, Katharina Förtsch, Heinz Ahlert, Joachim Rosenbauer, Christina Baechle, Michael Roden, Reinhard W Holl, Ertan Mayatepek, Sebastian Kummer, Thomas Meissner, Marc Jacobsen
Interleukin-7 receptor α-chain (IL7RA) haplotypes are associated with susceptibility for development of autoimmune diseases including Type 1 Diabetes (T1D). A protective IL7RA haplotype which causes lower soluble IL-7R (sIL-7R) serum levels is hypothesized to restrict IL-7-availability for self-reactive T-cells. Functional mechanisms affected by a risk-associated IL7RA haplotype are unknown. Here we investigated the influence of IL7RA haplotypes (tagged by rs6897932T for the protective or by rs1494555G for the risk haplotype) on sIL-7R and IL-7 serum concentrations as well as disease manifestation of children with T1D (n=259)...
February 27, 2018: Pediatric Diabetes
Roberto Perniola
About two decades ago, cloning of the autoimmune regulator ( AIRE ) gene materialized one of the most important actors on the scene of self-tolerance. Thymic transcription of genes encoding tissue-specific antigens (ts-ags) is activated by AIRE protein and embodies the essence of thymic self-representation. Pathogenic AIRE variants cause the autoimmune polyglandular syndrome type 1, which is a rare and complex disease that is gaining attention in research on autoimmunity. The animal models of disease, although not identically reproducing the human picture, supply fundamental information on mechanisms and extent of AIRE action: thanks to its multidomain structure, AIRE localizes to chromatin enclosing the target genes, binds to histones, and offers an anchorage to multimolecular complexes involved in initiation and post-initiation events of gene transcription...
2018: Frontiers in Immunology
Cristina Rius, Meriem Attaf, Katie Tungatt, Valentina Bianchi, Mateusz Legut, Amandine Bovay, Marco Donia, Per Thor Straten, Mark Peakman, Inge Marie Svane, Sascha Ott, Tom Connor, Barbara Szomolay, Garry Dolton, Andrew K Sewell
Peptide-MHC (pMHC) multimers, usually used as streptavidin-based tetramers, have transformed the study of Ag-specific T cells by allowing direct detection, phenotyping, and enumeration within polyclonal T cell populations. These reagents are now a standard part of the immunology toolkit and have been used in many thousands of published studies. Unfortunately, the TCR-affinity threshold required for staining with standard pMHC multimer protocols is higher than that required for efficient T cell activation. This discrepancy makes it possible for pMHC multimer staining to miss fully functional T cells, especially where low-affinity TCRs predominate, such as in MHC class II-restricted responses or those directed against self-antigens...
February 26, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
Bilin Dong, Zhongsheng Tong, Ruoyu Li, Sharon C-A Chen, Weihuang Liu, Wei Liu, Yao Chen, Xu Zhang, Yiqun Duan, Dongsheng Li, Liuqing Chen
Fonsecaea pedrosoi (F. pedrosoi) is the most common agent of chromoblastomycosis. Transformation of this fungus from its saprophytic phase into pathogenic sclerotic cells in tissue is an essential link to the refractoriness of this infection. Experimental studies in murine models have shown that the absence of CD4+ T cells impairs host defense against F. pedrosoi infection. Clinical research has also suggested that a relatively low level of the Th1 cytokine INF-γ and inefficient T cell proliferation are simultaneously present in patients with severe chromoblastomycosis upon in vitro stimulation with ChromoAg, an antigen prepared from F...
February 26, 2018: PLoS Neglected Tropical Diseases
Elena T Iakimova, Ernst J Woltering
In this work, the involvement of programmed cell death (PCD) in the wound-induced postharvest browning disorder and senescence in butterhead lettuce (Lactuca sativa L.) fresh-cuts was studied. At the wounded (cut, bruised) sites, rapid browning, loss of chlorophyll and massive cell death, accompanied with accumulation of reactive oxygen species and increased electrolyte leakage occurred in a narrow strip of tissue adjacent the injury. The dead cell morphology (protoplast and nuclei shrinkage) together with the biochemical and physiological changes resembled necrotic PCD type...
February 22, 2018: Protoplasma
Xuexiang Du, Mingyue Liu, Juanjuan Su, Peng Zhang, Fei Tang, Peiying Ye, Martin Devenport, Xu Wang, Yan Zhang, Yang Liu, Pan Zheng
Anti-CTLA-4 monoclonal antibodies (mAbs) confer a cancer immunotherapeutic effect (CITE) but cause severe immunotherapy-related adverse events (irAE). Targeting CTLA-4 has shown remarkable long-term benefit and thus remains a valuable tool for cancer immunotherapy if the irAE can be brought under control. An animal model, which recapitulates clinical irAE and CITE, would be valuable for developing safer CTLA-4-targeting reagents. Here, we report such a model using mice harboring the humanized Ctla4 gene. In this model, the clinically used drug, Ipilimumab, induced severe irAE especially when combined with an anti-PD-1 antibody; whereas another mAb, L3D10, induced comparable CITE with very mild irAE under the same conditions...
February 20, 2018: Cell Research
Mingfeng Zhang, Jeremy J Racine, Qing Lin, Yuqing Liu, Shanshan Tang, Qi Qin, Tong Qi, Arthur D Riggs, Defu Zeng
Autoimmune type 1 diabetes (T1D) and other autoimmune diseases are associated with particular MHC haplotypes and expansion of autoreactive T cells. Induction of MHC-mismatched but not -matched mixed chimerism by hematopoietic cell transplantation effectively reverses autoimmunity in diabetic nonobese diabetic (NOD) mice, even those with established diabetes. As expected, MHC-mismatched mixed chimerism mediates deletion in the thymus of host-type autoreactive T cells that have T-cell receptor (TCR) recognizing (cross-reacting with) donor-type antigen presenting cells (APCs), which have come to reside in the thymus...
February 20, 2018: Proceedings of the National Academy of Sciences of the United States of America
Jinbo Yu, Vu Huy Hoang Duong, Katrin Westphal, Andreas Westphal, Abdulhadi Suwandi, Guntram A Grassl, Korbinian Brand, Andrew C Chan, Niko Föger, Kyeong-Hee Lee
The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model, while, in a chronic inflammatory context, was associated with reduced immunopathological tissue damage...
February 20, 2018: Journal of Clinical Investigation
Marta Rydzewska, Michał Jaromin, Izabela Elżbieta Pasierowska, Karlina Stożek, Artur Bossowski
Autoimmune thyroid disorders (AITD) broadly include Graves' disease and Hashimoto's thyroiditis which are the most common causes of thyroid gland dysfunctions. These disorders develop due to complex interactions between environmental and genetic factors and are characterized by reactivity to self-thyroid antigens due to autoreactive lymphocytes escaping tolerance. Both cell-mediated and humoral responses lead to tissue injury in autoimmune thyroid disease. The differentiation of CD4+ cells in the specific setting of immune mediators (for example cytokines, chemokines) results in differentiation of various T cell subsets...
2018: Thyroid Research
Giuseppina Conteduca, Francesco Indiveri, Gilberto Filaci, Simone Negrini
The autoimmune regulator gene (AIRE) is a transcription factor expressed both in the thymus, by medullary thymic epithelial cells, and in secondary lymphoid organs. AIRE controls the local transcription of organ- specific proteins typically expressed in peripheral tissues, thus allowing the negative selection of self- reactive T cells. The crucial role played by AIRE in central immune tolerance emerged in the studies on the pathogenesis of Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy, a rare inherited polyendocrine/autoimmune disease...
February 8, 2018: Autoimmunity Reviews
Elien M Doorduijn, Marjolein Sluijter, Bianca J Querido, Ursula J E Seidel, Claudia C Oliveira, Sjoerd H van der Burg, Thorbald van Hall
The HLA-E homolog in the mouse (Qa-1b) is a conserved MHC class Ib molecule presenting monomorphic peptides to germline-encoded natural killer receptor CD94/NKG2A. Previously, we demonstrated the replacement of this canonical peptide by a diverse peptidome upon deficiency of the TAP peptide transporter. Analysis of this Qa-1b-restricted T cell repertoire against these non-mutated neoantigens revealed characteristics of conventional hypervariable CD8+ T cells, but also of invariant T cell receptor (TCR)αβ T cells...
2018: Frontiers in Immunology
Jin Yan Yap, Rushika C Wirasinha, Anna Chan, Debbie R Howard, Christopher C Goodnow, Stephen R Daley
Acquisition of T cell central tolerance involves distinct pathways of self-antigen presentation to thymocytes. One pathway termed indirect presentation requires a self-antigen transfer step from thymic epithelial cells (TECs) to bone marrow (BM)-derived cells before the self-antigen is presented to thymocytes. The role of indirect presentation in central tolerance is context-dependent, potentially due to variation in self-antigen expression, processing and presentation in the thymus. Here, we report experiments in mice in which TECs expressed a membrane-bound transgenic self-antigen, hen egg lysozyme (HEL), from either the insulin (insHEL) or thyroglobulin (thyroHEL) promoter...
February 7, 2018: Immunology
Marco Bo, Magdalena Niegowska, Gian Luca Erre, Marco Piras, Maria Giovanna Longu, Pierangela Manchia, Mario Manca, Giuseppe Passiu, Leonardo A Sechi
Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by a progressive joint damage due to largely unknown environmental factors acting in concert with risk alleles conferring genetic susceptibility. A major role has been attributed to viral infections that include past contacts with Epstein-Barr virus (EBV) and, more recently, to non-protein coding sequences of human endogenous retrovirus K (HERV-K) integrated in the human genome. Molecular mimicry between viral and self proteins is supposed to cause the loss of immune tolerance in predisposed hosts...
January 29, 2018: Scientific Reports
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