scholarly journals Genetic Ablation of the Mitochondrial Calcium Uniporter (MCU) Does not Impair T Cell-Mediated Immunity In Vivo

2021 ◽  
Vol 12 ◽  
Author(s):  
Hao Wu ◽  
Benjamin Brand ◽  
Miriam Eckstein ◽  
Sophia M. Hochrein ◽  
Magdalena Shumanska ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Antigen Receptor ◽  
Building Blocks ◽  
Effector Function ◽  
Metabolic Reprogramming ◽  
T Cell Subsets ◽  
Cell Mediated Immunity ◽  
Receptor Stimulation ◽  
Genetic Ablation

T cell activation and differentiation is associated with metabolic reprogramming to cope with the increased bioenergetic demand and to provide metabolic intermediates for the biosynthesis of building blocks. Antigen receptor stimulation not only promotes the metabolic switch of lymphocytes but also triggers the uptake of calcium (Ca2+) from the cytosol into the mitochondrial matrix. Whether mitochondrial Ca2+ influx through the mitochondrial Ca2+ uniporter (MCU) controls T cell metabolism and effector function remained, however, enigmatic. Using mice with T cell-specific deletion of MCU, we here show that genetic inactivation of mitochondrial Ca2+ uptake increased cytosolic Ca2+ levels following antigen receptor stimulation and store-operated Ca2+ entry (SOCE). However, ablation of MCU and the elevation of cytosolic Ca2+ did not affect mitochondrial respiration, differentiation and effector function of inflammatory and regulatory T cell subsets in vitro and in animal models of T cell-mediated autoimmunity and viral infection. These data suggest that MCU-mediated mitochondrial Ca2+ uptake is largely dispensable for murine T cell function. Our study has also important technical implications. Previous studies relied mostly on pharmacological inhibition or transient knockdown of mitochondrial Ca2+ uptake, but our results using mice with genetic deletion of MCU did not recapitulate these findings. The discrepancy of our study to previous reports hint at compensatory mechanisms in MCU-deficient mice and/or off-target effects of current MCU inhibitors.

scholarly journals Early Immune Markers Associated withMycobacterium aviumsubsp.paratuberculosisInfection in a Neonatal Calf Model

2011 ◽  
Vol 18 (3) ◽  
pp. 393-405 ◽  
Author(s):  
J. R. Stabel ◽  
S. Robbe-Austerman
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Lymphocyte Proliferation ◽  
Cell Activation ◽  
The Other ◽  
T Cell Subsets ◽  
Cell Mediated Immunity ◽  
Activation Markers ◽  
Oral Inoculation ◽  
Ifn Γ

ABSTRACTThe objective of this study was to observe early markers of cell-mediated immunity in naïve calves infected withMycobacterium aviumsubsp.paratuberculosisand how expression of these markers evolved over the 12-month period of infection. Groups for experimental infection included control (noninfected), oral (infected orally withM. aviumsubsp.paratuberculosisstrain K-10), oral/DXM (pretreatment with dexamethasone before oral inoculation), intraperitoneal (i.p.) inoculation, and oral/M (oral inoculation with mucosal scrapings from a cow with clinical disease) groups. One of the earliest markers to emerge was antigen-specific gamma interferon (IFN-γ). Only i.p. inoculated calves had detectable antigen-specific IFN-γ responses at 7 days, with responses of the other infection groups becoming detectable at 90 and 120 days. All infection groups maintained robust IFN-γ responses for the remainder of the study. At 1 month, calves in the oral and oral/M groups had higher antigen-stimulated interleukin-10 (IL-10) levels than calves in the other treatment groups, but IL-10 secretion declined by 12 months for all calves. T-cell activation markers such as CD25, CD26, CD45RO, and CD5 were significantly upregulated in infected calves compared to noninfected controls. Oral inoculation of calves resulted in significantly increased antigen-specific lymphocyte proliferation at 9 and 12 months, as well as inducible nitric oxide synthase (iNOS) secretion at 6 and 12 months. These results demonstrate that infection of naïve calves withM. aviumsubsp.paratuberculosisinvoked early immunologic responses characterized by robust antigen-specific IFN-γ responses and induction of CD25 and CD45RO expression on T-cell subsets. These were followed by antigen-specific lymphocyte proliferation, iNOS secretion, and expression of CD26 and CD5brightmarkers in the latter part of the 12-month study.

scholarly journals Fundamentals of T Cell Metabolism and Strategies to Enhance Cancer Immunotherapy

2021 ◽  
Vol 12 ◽  
Author(s):  
Guillermo O. Rangel Rivera ◽  
Hannah M. Knochelmann ◽  
Connor J. Dwyer ◽  
Aubrey S. Smith ◽  
Megan M. Wyatt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Metabolic Pathways ◽  
Cell Activation ◽  
Cell Metabolism ◽  
Building Blocks ◽  
Cell Mediated Immunity ◽  
Cytotoxic Molecules ◽  
Checkpoint Receptors

Emerging reports show that metabolic pathways can be targeted to enhance T cell-mediated immunity to tumors. Yet, tumors consume key metabolites in the host to survive, thus robbing T cells of these nutrients to function and thrive. T cells are often deprived of basic building blocks for energy in the tumor, including glucose and amino acids needed to proliferate or produce cytotoxic molecules against tumors. Immunosuppressive molecules in the host further compromise the lytic capacity of T cells. Moreover, checkpoint receptors inhibit T cell responses by impairing their bioenergetic potential within tumors. In this review, we discuss the fundamental metabolic pathways involved in T cell activation, differentiation and response against tumors. We then address ways to target metabolic pathways to improve the next generation of immunotherapies for cancer patients.

scholarly journals Reduced CD5 on CD8+ T Cells in Tumors but Not Lymphoid Organs Is Associated With Increased Activation and Effector Function

2021 ◽  
Vol 11 ◽  
Author(s):  
Faizah Alotaibi ◽  
Mark Vincent ◽  
Wei-Ping Min ◽  
James Koropatnick
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Tumor Infiltrating Lymphocytes ◽  
Effector Function ◽  
Lymphoid Organs ◽  
T Cell Subsets ◽  
Peripheral Organs

CD5, a member of the scavenger receptor cysteine-rich superfamily, is a marker for T cells and a subset of B cells (B1a). CD5 associates with T-cell and B-cell receptors and increased CD5 is an indication of B cell activation. In tumor-infiltrating lymphocytes (TILs) isolated from lung cancer patients, CD5 levels were negatively correlated with anti-tumor activity and tumor‐mediated activation-induced T cell death, suggesting that CD5 could impair activation of anti-tumor T cells. We determined CD5 levels in T cell subsets in different organs in mice bearing syngeneic 4T1 breast tumor homografts and assessed the relationship between CD5 and increased T cell activation and effector function by flow cytometry. We report that T cell CD5 levels were higher in CD4+ T cells than in CD8+ T cells in 4T1 tumor-bearing mice, and that high CD5 levels on CD4+ T cells were maintained in peripheral organs (spleen and lymph nodes). However, both CD4+ and CD8+ T cells recruited to tumors had reduced CD5 compared to CD4+ and CD8+ T cells in peripheral organs. In addition, CD5high/CD4+ T cells and CD5high/CD8+ T cells from peripheral organs exhibited higher levels of activation and associated effector function compared to CD5low/CD4+ T cell and CD5low/CD8+ T cell from the same organs. Interestingly, CD8+ T cells among TILs and downregulated CD5 were activated to a higher level, with concomitantly increased effector function markers, than CD8+/CD5high TILs. Thus, differential CD5 levels among T cells in tumors and lymphoid organs can be associated with different levels of T cell activation and effector function, suggesting that CD5 may be a therapeutic target for immunotherapeutic activation in cancer therapy.

Effect of hyperbaric oxygen on tissue distribution of mononuclear cell subsets in the rat

1994 ◽  
Vol 77 (5) ◽  
pp. 2355-2359 ◽  
Author(s):  
N. Bitterman ◽  
N. Lahat ◽  
T. Rosenwald ◽  
A. Kinarty ◽  
Y. Melamed ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Hyperbaric Oxygen ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Interleukin 2 ◽  
T Cell Subsets ◽  
Cell Mediated Immunity ◽  
Lymph Glands

In a previous study we found a significant temporary decrease in the ratio of CD4/CD8 (helper, inducer/suppressor, cytotoxic) T lymphocytes in the peripheral blood of healthy human volunteers after exposure to a single commonly used profile of hyperbaric oxygen (HBO). The transient nature of the changes suggested redistribution of T-cell subsets. The purpose of the present study was to verify such a redistribution and to locate possible target organs in an animal model. A single exposure of rats to HBO (0.28 MPa) induced a highly significant rapid decrease in the CD4/CD8 ratio in peripheral blood count (P < 0.0001), confirming our previous findings in humans. HBO also induced a significant increase in the CD4/CD8 ratio in the lungs and lymph nodes (P < 0.001) and a significant decrease in the ratio in the spleen (P < 0.01). Furthermore, exposure to HBO induced a significant increase in T cells bearing surface interleukin-2 receptors in the blood, spleen, lungs, and lymph glands (P < 0.001) and a significant decrease in T cells expressing alpha beta-receptors in the lungs (P < 0.001) and lymph glands (P < 0.05). Our findings suggest rapid T-cell activation after a brief exposure to HBO, with shifts of CD4 and CD8 subsets and variations in T-cell receptor type. These rapid changes in the parameters of cell-mediated immunity may represent the activation of protective mechanisms against the toxic effect of oxygen or the early stages of pulmonary oxygen toxicity.

scholarly journals Quantitative analysis and genome-scale modeling of human CD4+ T-cell differentiation reveals subset-specific regulation of glycosphingolipid pathways

2021 ◽  
Author(s):  
Partho Sen ◽  
Syed Bilal Ahmad Andrabi ◽  
Tanja Buchacher ◽  
Mohd Moin Khan ◽  
Ubaid Ullah ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Th17 Cells ◽  
Functional Differentiation ◽  
Metabolic Reprogramming ◽  
Gene Knockdown ◽  
T Cell Subsets ◽  
Genome Scale

ABSTRACTT-cells are sentinels of adaptive cell-mediated immune responses. T-cell activation, proliferation and differentiation involves metabolic reprogramming involving the interplay of genes, proteins and metabolites. Here, we aim to understand the metabolic pathways involved in the activation and functional differentiation of human CD4+ T-cell subsets (Th1, Th2, Th17 and iTregs). We combined genome-scale metabolic modeling, gene expression data, targeted and non-targeted lipidomics experiments, together with in vitro gene knockdown experiments and showed that human CD4+ T-cells undergo specific metabolic changes during activation and functional differentiation. In addition, we identified and confirmed the importance of ceramide and glycosphingolipid synthesis pathways in Th17 differentiation and effector functions. Finally, through in vitro gene knockdown experiments, we substantiated the requirement of serine palmitoyl transferase (SPT), a de novo sphingolipid pathway in the expression of proinflammatory cytokine (IL17A and IL17F) by Th17 cells. Our findings may provide a comprehensive resource for identifying CD4+ T-cell-specific targets for their selective manipulation under disease conditions, particularly, diseases characterized by an imbalance of Treg / Th17 cells. Our data also suggest a role for elevated levels of ceramides in conditions comorbid with these diseases, e.g., obesity and insulin resistance.

scholarly journals The Role of Non-essential Amino Acids in T Cell Function and Anti-tumour Immunity

2021 ◽  
Vol 69 (1) ◽  
Author(s):  
Helen Carrasco Hope ◽  
Robert J. Salmond
Keyword(s):  
Amino Acids ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Metabolic Pathways ◽  
Cell Metabolism ◽  
Building Blocks ◽  
Essential Amino Acids ◽  
Metabolic Reprogramming ◽  
Tumour Immunity

AbstractT cell activation, differentiation and proliferation is dependent upon and intrinsically linked to a capacity to modulate and adapt cellular metabolism. Antigen-induced activation stimulates a transcriptional programme that results in metabolic reprogramming, enabling T cells to fuel anabolic metabolic pathways and provide the nutrients to sustain proliferation and effector responses. Amino acids are key nutrients for T cells and have essential roles as building blocks for protein synthesis as well as in numerous metabolic pathways. In this review, we discuss the roles for uptake and biosynthesis of non-essential amino acids in T cell metabolism, activation and effector function. Furthermore, we highlight the effects of amino acid metabolism and depletion by cancer cells on T cell anti-tumour function and discuss approaches to modulate and improve T cell metabolism for improved anti-tumour function in these nutrient-depleted microenvironments.

T-cell Activation Induces Dynamic Changes in miRNA Expression Patterns in CD4 and CD8 T-cell Subsets

MicroRNA ◽  
2015 ◽  
Vol 4 (2) ◽  
pp. 117-122 ◽  
Author(s):  
Nato Teteloshvili ◽  
Katarzyna Smigielska-Czepiel ◽  
Bart-Jan Kroesen ◽  
Elisabeth Brouwer ◽  
Joost Kluiver ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Mirna Expression ◽  
Cell Activation ◽  
Expression Patterns ◽  
Cd8 T Cell ◽  
T Cell Subsets ◽  
Dynamic Changes

scholarly journals Vitamin D Supplementation Modulates T Cell–Mediated Immunity in Humans: Results from a Randomized Control Trial

2016 ◽  
Vol 101 (2) ◽  
pp. 533-538 ◽  
Author(s):  
Gauree Gupta Konijeti ◽  
Pankaj Arora ◽  
Matthew R. Boylan ◽  
Yanna Song ◽  
Shi Huang ◽  
...  
Keyword(s):  
Vitamin D ◽  
T Cell ◽  
Vitamin D Deficiency ◽  
T Cell Activation ◽  
Vitamin D3 ◽  
Cell Activation ◽  
Atp Release ◽  
High Dose ◽  
Cell Mediated Immunity ◽  
Ancillary Study

Abstract Context: Although studies have linked vitamin D deficiency with immune-mediated diseases, data demonstrating a direct effect on T-cell function are sparse. Objective: Our objective was to determine whether oral vitamin D3 influences T-cell activation in humans with vitamin D deficiency. Design: This was a single-center ancillary study within Vitamin D Therapy in Individuals at High Risk of Hypertension, a double-blind, multicenter, randomized controlled trial. Setting: This study was undertaken in a single academic medical center. Participants: Adults with vitamin D deficiency and untreated pre- or early stage I hypertension were included. Intervention: In Vitamin D Therapy in Individuals at High Risk of Hypertension, participants were randomized to either low- (400 IU daily) or high- (4000 IU daily) dose oral vitamin D3 for 6 months. In this ancillary study of 38 patients, we measured CD4+ T-cell activation estimated by intracellular ATP release after stimulation of whole blood with plant lectin phytohemagglutinin collected at baseline (pretreatment) and 2-month follow-up. Main Outcome Measure: Determining whether ATP level changes were significantly different between treatment groups was the main outcome measure. Results: Treatment with 4000 IU of vitamin D3 decreased intracellular CD4+ ATP release by 95.5 ng/ml (interquartile range, −219.5 to 105.8). In contrast, 400 IU of vitamin D3 decreased intracellular CD4+ ATP release by 0.5 ng/ml (interquartile range, −69.2 to 148.5). In a proportional odds model, high-dose vitamin D3 was more likely than low-dose vitamin D3 to decrease CD4+ ATP release (odds ratio, 3.43; 95% confidence interval, 1.06–1.11). Conclusions: In this ancillary study of a randomized controlled trial, we found that high-dose vitamin D3 significantly reduced CD4+ T-cell activation compared to low-dose vitamin D3, providing human evidence that vitamin D can influence cell-mediated immunity.

scholarly journals CD122-directed interleukin-2 treatment mechanisms in bladder cancer differ from αPD-L1 and include tissue-selective γδ T cell activation

2021 ◽  
Vol 9 (4) ◽  
pp. e002051
Author(s):  
Ryan Michael Reyes ◽  
Yilun Deng ◽  
Deyi Zhang ◽  
Niannian Ji ◽  
Neelam Mukherjee ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Combination Treatment ◽  
Treatment Efficacy ◽  
Interleukin 2 ◽  
Γδ T Cells ◽  
T Cell Subsets ◽  
Γδ T Cell

BackgroundAnti-programmed death-ligand 1 (αPD-L1) immunotherapy is approved to treat bladder cancer (BC) but is effective in <30% of patients. Interleukin (IL)-2/αIL-2 complexes (IL-2c) that preferentially target IL-2 receptor β (CD122) augment CD8+ antitumor T cells known to improve αPD-L1 efficacy. We hypothesized that the tumor microenvironment, including local immune cells in primary versus metastatic BC, differentially affects immunotherapy responses and that IL-2c effects could differ from, and thus complement αPD-L1.MethodsWe studied mechanisms of IL-2c and αPD-L1 efficacy using PD-L1+ mouse BC cell lines MB49 and MBT-2 in orthotopic (bladder) and metastatic (lung) sites.ResultsIL-2c reduced orthotopic tumor burden and extended survival in MB49 and MBT-2 BC models, similar to αPD-L1. Using antibody-mediated cell depletions and genetically T cell-deficient mice, we unexpectedly found that CD8+ T cells were not necessary for IL-2c efficacy against tumors in bladder, whereas γδ T cells, not reported to contribute to αPD-L1 efficacy, were indispensable for IL-2c efficacy there. αPD-L1 responsiveness in bladder required conventional T cells as expected, but not γδ T cells, altogether defining distinct mechanisms for IL-2c and αPD-L1 efficacy. γδ T cells did not improve IL-2c treatment of subcutaneously challenged BC or orthotopic (peritoneal) ovarian cancer, consistent with tissue-specific and/or tumor-specific γδ T cell contributions to IL-2c efficacy. IL-2c significantly altered bladder intratumoral γδ T cell content, activation status, and specific γδ T cell subsets with antitumor or protumor effector functions. Neither IL-2c nor αPD-L1 alone treated lung metastatic MB49 or MBT-2 BC, but their combination improved survival in both models. Combination treatment efficacy in lungs required CD8+ T cells but not γδ T cells.ConclusionsMechanistic insights into differential IL-2c and αPD-L1 treatment and tissue-dependent effects could help develop rational combination treatment strategies to improve treatment efficacy in distinct cancers. These studies also provide insights into γδ T cell contributions to immunotherapy in bladder and engagement of adaptive immunity by IL-2c plus αPD-L1 to treat refractory lung metastases.

scholarly journals Removal of C-Terminal Src Kinase from the Immune Synapse by a New Binding Protein

2005 ◽  
Vol 25 (6) ◽  
pp. 2227-2241 ◽  
Author(s):  
Souad Rahmouni ◽  
Torkel Vang ◽  
Andres Alonso ◽  
Scott Williams ◽  
Marianne van Stipdonk ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Interleukin 2 ◽  
Antigen Receptor ◽  
T Cell Antigen Receptor ◽  
Intracellular Location ◽  
Immune Synapse ◽  
Cell Antigen Receptor ◽  
Cell Antigen

ABSTRACT The Csk tyrosine kinase negatively regulates the Src family kinases Lck and Fyn in T cells. Engagement of the T-cell antigen receptor results in a removal of Csk from the lipid raft-associated transmembrane protein PAG/Cbp. Instead, Csk becomes associated with an ∼72-kDa tyrosine-phosphorylated protein, which we identify here as G3BP, a phosphoprotein reported to bind the SH3 domain of Ras GTPase-activating protein. G3BP reduced the ability of Csk to phosphorylate Lck at Y505 by decreasing the amount of Csk in lipid rafts. As a consequence, G3BP augmented T-cell activation as measured by interleukin-2 gene activation. Conversely, elimination of endogenous G3BP by RNA interference increased Lck Y505 phosphorylation and reduced TCR signaling. In antigen-specific T cells, endogenous G3BP moved into a intracellular location adjacent to the immune synapse, but deeper inside the cell, upon antigen recognition. Csk colocalization with G3BP occurred in this “parasynaptic” location. We conclude that G3BP is a new player in T-cell-antigen receptor signaling and acts to reduce the amount of Csk in the immune synapse.

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