scholarly journals The Role of Macrophages in T Cell–mediated Autoimmune Diabetes in Nonobese Diabetic Mice

1999 ◽  
Vol 189 (2) ◽  
pp. 347-358 ◽  
Author(s):  
Hee-Sook Jun ◽  
Chang-Soon Yoon ◽  
Lori Zbytnuik ◽  
Nico van Rooijen ◽  
Ji-Won Yoon
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Autoimmune Diabetes ◽  
Cytotoxic T Cells ◽  
Nod Mice ◽  
Β Cell ◽  
Prevention Of Diabetes

We have shown previously that the inactivation of macrophages in nonobese diabetic (NOD) mice results in the prevention of diabetes; however, the mechanisms involved remain unknown. In this study, we found that T cells in a macrophage-depleted environment lost their ability to differentiate into β cell–cytotoxic T cells, resulting in the prevention of autoimmune diabetes, but these T cells regained their β cell–cytotoxic potential when returned to a macrophage-containing environment. To learn why T cells in a macrophage-depleted environment lose their ability to kill β cells, we examined the islet antigen–specific immune response and T cell activation in macrophage-depleted NOD mice. There was a shift in the immune balance, a decrease in the T helper cell type 1 (Th1) immune response, and an increase in the Th2 immune response, due to the reduced expression of the macrophage-derived cytokine IL-12. As well, there was a deficit in T cell activation, evidenced by significant decreases in the expression of Fas ligand and perforin. The administration of IL-12 substantially reversed the prevention of diabetes in NOD mice conferred by macrophage depletion. We conclude that macrophages play an essential role in the development and activation of β cell–cytotoxic T cells that cause β cell destruction, resulting in autoimmune diabetes in NOD mice.

scholarly journals MerTK is required for apoptotic cell–induced T cell tolerance

2008 ◽  
Vol 205 (1) ◽  
pp. 219-232 ◽  
Author(s):  
Mark A. Wallet ◽  
Pradip Sen ◽  
Rafael R. Flores ◽  
Yaming Wang ◽  
Zuoan Yi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Autoimmune Diabetes ◽  
Apoptotic Cell ◽  
Critical Role ◽  
Costimulatory Molecule ◽  
Nod Mice ◽  
Β Cell

Self-antigens expressed by apoptotic cells (ACs) may become targets for autoimmunity. Tolerance to these antigens is partly established by an ill-defined capacity of ACs to inhibit antigen-presenting cells such as dendritic cells (DCs). We present evidence that the receptor tyrosine kinase Mer (MerTK) has a key role in mediating AC-induced inhibition of DC activation/maturation. Pretreatment of DCs prepared from nonobese diabetic (NOD) mice with AC blocked secretion of proinflammatory cytokines, up-regulation of costimulatory molecule expression, and T cell activation. The effect of ACs on DCs was dependent on Gas6, which is a MerTK ligand. NOD DCs lacking MerTK expression (NOD.MerTKKD/KD) were resistant to AC-induced inhibition. Notably, autoimmune diabetes was exacerbated in NOD.MerTKKD/KD versus NOD mice expressing the transgenic BDC T cell receptor. In addition, β cell–specific CD4+ T cells adoptively transferred into NOD.MerTKKD/KD mice in which β cell apoptosis was induced with streptozotocin exhibited increased expansion and differentiation into type 1 T cell effectors. In both models, the lack of MerTK expression was associated with an increased frequency of activated pancreatic CD11c+CD8α+ DCs, which exhibited an enhanced T cell stimulatory capacity. These findings demonstrate that MerTK plays a critical role in regulating self-tolerance mediated between ACs, DCs, and T cells.

scholarly journals CD28-B7 interactions allow the induction of CD8+ cytotoxic T lymphocytes in the absence of exogenous help.

1993 ◽  
Vol 177 (6) ◽  
pp. 1791-1796 ◽  
Author(s):  
F A Harding ◽  
J P Allison
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cytotoxic T Cells ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Histocompatibility Complex ◽  
Necessary And Sufficient ◽  
Additional Antigen

The activation requirements for the generation of CD8+ cytotoxic T cells (CTL) are poorly understood. Here we demonstrate that in the absence of exogenous help, a CD28-B7 interaction is necessary and sufficient for generation of class I major histocompatibility complex-specific CTL. Costimulation is required only during the inductive phase of the response, and not during the effector phase. Transfection of the CD28 counter receptor, B7, into nonstimulatory P815 cells confers the ability to elicit P815-specific CTL, and this response can be inhibited by anti-CD28 Fab or by the chimeric B7-binding protein CTLA4Ig. Anti-CD28 monoclonal antibody (mAb) can provide a costimulatory signal to CD8+ T cells when the costimulatory capacity of splenic stimulators is destroyed by chemical fixation. CD28-mediated signaling provokes the release of interleukin 2 (IL-2) from the CD8+ CTL precursors, as anti-CD28 mAb could be substituted for by the addition of IL-2, and an anti-IL-2 mAb can block the generation of anti-CD28-induced CTL. CD4+ cells are not involved in the costimulatory response in the systems examined. We conclude that CD8+ T cell activation requires two signals: an antigen-specific signal mediated by the T cell receptor, and an additional antigen nonspecific signal provided via a CD28-B7 interaction.

scholarly journals Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19

2020 ◽  
Author(s):  
Anno Saris ◽  
Tom D.Y. Reijnders ◽  
Esther J. Nossent ◽  
Alex R. Schuurman ◽  
Jan Verhoeff ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Effector Memory ◽  
Activated T Cells ◽  
Immune Profile ◽  
Prolonged Icu Stay

AbstractOur understanding of the coronavirus disease-19 (COVID-19) immune response is almost exclusively derived from studies that examined blood. To gain insight in the pulmonary immune response we analysed BALF samples and paired blood samples from 17 severe COVID-19 patients. Macrophages and T cells were the most abundant cells in BALF. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells and expressed higher levels of the exhaustion marker PD-1 than in peripheral blood. Prolonged ICU stay associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma. In conclusion, the bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood.SummaryThe bronchoalveolar immune response in severe COVID-19 strongly differs from the peripheral blood immune profile. Fatal COVID-19 associated with T cell activation blood, but not in BALF.

Regulation of Tim-3 function by binding to phosphatidylserine

2021 ◽  
Vol 478 (22) ◽  
pp. 3999-4004
Author(s):  
Lawrence P. Kane
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Cytotoxic T Cells ◽  
Cross Presentation ◽  
First Time

Tim-3 is a transmembrane protein that is highly expressed on subsets of chronically stimulated CD4+ helper and CD8+ cytotoxic T cells, with more transient expression during acute activation and infection. Tim-3 is also constitutively expressed by multiple types of myeloid cells. Like other TIM family members, Tim-3 can bind to phosphatidylserine displayed by apoptotic cells, and this interaction has been shown to mediate uptake of such cells by dendritic cells and cross-presentation of antigens to CD8+ T cells. In contrast, how the recognition of PS by Tim-3 might regulate the function of Tim-3+ T cells is not known. In their recent paper, Lemmon and colleagues demonstrate for the first time that recognition of PS by Tim-3 leads to enhanced T cell activation.

Immunotherapy of B-Cell Lymphoma With CD3x19 Bispecific Antibodies: Costimulation via CD28 Prevents “Veto” Apoptosis of Antibody-Targeted Cytotoxic T Cells

Blood ◽  
1998 ◽  
Vol 92 (12) ◽  
pp. 4750-4757 ◽  
Author(s):  
Peter T. Daniel ◽  
Arne Kroidl ◽  
Joachim Kopp ◽  
Isrid Sturm ◽  
Gerhard Moldenhauer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cytotoxic T Cells ◽  
B Cell Lymphoma ◽  
Bispecific Antibodies ◽  
Lymphoma Cells ◽  
B Lymphoma ◽  
B Lymphoma Cells

Bispecific antibodies (CD3x19) against the CD3ɛ-chain of the T-cell–receptor/CD3 complex and the CD19 antigen on B cells can target polyclonal, nontumor-specific T cells to B lymphoma cells. This induces T-cell activation, and generation of cytotoxic T cells (CTLs). These polyclonal CTLs, targeted by the CD3x19 bispecific antibodies, can lyse CD19+ B-lymphoma cells. In a xenotransplant model in severe combined immunodeficiency deficient (SCID) mice, we and others observed that CD28 triggering is required for efficient elimination of B-lymphoma cells and cure from the tumor in addition to CD3x19 administration. We also showed that the activation and targeting of CTLs to the target cell by signal one alone, ie, the CD3x19 mab, induces T-cell death by apoptosis. In blocking experiments we showed that this “veto” apoptosis is mediated by the CD95/Fas ligand. Addition of anti-CD28 (signal 2) renders the T cells resistant for veto apoptosis both in vitro and in vivo. We therefore conclude that the role of costimulation in immunotherapy with bispecific antibodies or other T-cell–based immune strategies is not only to facilitate T-cell activation but also to prevent T-cell deletion by apoptosis.

scholarly journals Initiation of Autoimmune Diabetes by Developmentally Regulated Presentation of Islet Cell Antigens in the Pancreatic Lymph Nodes

1999 ◽  
Vol 189 (2) ◽  
pp. 331-339 ◽  
Author(s):  
Petter Höglund ◽  
Justine Mintern ◽  
Caroline Waltzinger ◽  
William Heath ◽  
Christophe Benoist ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Beta Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Molecular Mimicry ◽  
Autoimmune Diabetes ◽  
Activated T Cells ◽  
Pancreatic Lymph Nodes

Little is known about the events triggering lymphocyte invasion of the pancreatic islets in prelude to autoimmune diabetes. For example, where islet-reactive T cells first encounter antigen has not been identified. We addressed this issue using BDC2.5 T cell receptor transgenic mice, which express a receptor recognizing a natural islet beta cell antigen. In BDC2.5 animals, activated T cells were found only in the islets and the lymph nodes draining them, and there was a close temporal correlation between lymph node T cell activation and islet infiltration. When naive BDC2.5 T cells were transferred into nontransgenic recipients, proliferating cells were observed only in pancreatic lymph nodes, and this occurred significantly before insulitis was detectable. Surprisingly, proliferation was not seen in 10-day-old recipients. This age-dependent dichotomy was reproduced in a second transfer system based on an unrelated antigen artificially expressed on beta cells. We conclude that beta cell antigens are transported specifically to pancreatic lymph nodes, where they trigger reactive T cells to invade the islets. Systemic or extrapancreatic T cell priming, indicative of activation via molecular mimicry or superantigens, was not seen. Compromised presentation of beta cell antigens in the pancreatic lymph nodes of juvenile animals may be the root of a first “checkpoint” in diabetes progression.

An emerging player in the adaptive immune response: microRNA-146a is a modulator of IL-2 expression and activation-induced cell death in T lymphocytes

Blood ◽  
2010 ◽  
Vol 115 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Graziella Curtale ◽  
Franca Citarella ◽  
Claudia Carissimi ◽  
Marina Goldoni ◽  
Nicoletta Carucci ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Activation ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Activation Induced Cell Death

Abstract Activation of the T cell–mediated immune response has been associated with changes in the expression of specific microRNAs (miRNAs). However, the role of miRNAs in the development of an effective immune response is just beginning to be explored. This study focuses on the functional role of miR-146a in T lymphocyte–mediated immune response and provides interesting clues on the transcriptional regulation of miR-146a during T-cell activation. We show that miR-146a is low in human naive T cells and is abundantly expressed in human memory T cells; consistently, miR-146a is induced in human primary T lymphocytes upon T-cell receptor (TCR) stimulation. Moreover, we identified NF-kB and c-ETS binding sites as required for the induction of miR-146a transcription upon TCR engagement. Our results demonstrate that several signaling pathways, other than inflammation, are influenced by miR-146a. In particular, we provide experimental evidence that miR-146a modulates activation-induced cell death (AICD), acting as an antiapoptotic factor, and that Fas-associated death domain (FADD) is a target of miR-146a. Furthermore, miR-146a enforced expression impairs both activator protein 1 (AP-1) activity and interleukin-2 (IL-2) production induced by TCR engagement, thus suggesting a role of this miRNA in the modulation of adaptive immunity.

scholarly journals Loss of Zbtb32 in NOD mice does not significantly alter T cell responses.

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 318
Author(s):  
William D. Coley ◽  
Yongge Zhao ◽  
Charles J. Benck ◽  
Yi Liu ◽  
Chie Hotta-Iwamura ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nod Mice ◽  
Diabetes Incidence ◽  
T Cell Tolerance ◽  
Cell Tolerance

Background: We previously identified the transcriptional regulator Zbtb32 as a factor that can promote T cell tolerance in the Non-Obese Diabetic (NOD) mouse, a model of Type 1 diabetes. Antigen targeted to DCIR2+ dendritic cells (DCs) in vivo inhibited both diabetes and effector T cell expansion in NOD mice. Furthermore, Zbtb32 was preferentially induced in autoreactive CD4 T cells stimulated by these tolerogenic DCIR2+ DCs, and overexpression of Zbtb32 in islet-specific T cells inhibited the diabetes development by limiting T cell proliferation and cytokine production. Methods: To further understand the role of Zbtb32 in T cell tolerance induction, we have now used CRISPR to target the Zbtb32 gene for deletion directly in NOD mice and characterized the mutant mice. We hypothesized that the systemic loss of Zbtb32 in NOD mice would lead to increased T cell activation and increased diabetes pathogenesis. Results: Although NOD.Zbtb32-/- male NOD mice showed a trend towards increased diabetes incidence compared to littermate controls, the difference was not significant. Furthermore, no significant alteration in lymphocyte number or function was observed. Importantly, in vitro stimulation of lymphocytes from NOD.Zbtb32-/- mice did not produce the expected hypersensitive phenotype observed in other genetic strains, potentially due to compensation by homologous genes. Conclusions: The loss of Zbtb32 in the NOD background does not result in the expected T cell activation phenotype.

scholarly journals Engineering T-Cell Activation for Immunotherapy by Mechanical Forces

2021 ◽  
pp. 553-591
Author(s):  
Elena Locci ◽  
Silvia Raymond
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cytotoxic T Cells ◽  
Cancer Therapies ◽  
Physical Barriers ◽  
Keywords Cancer ◽  
New Cancer Therapies

A groundbreaking study led by engineering and medical researchers at the California South University (CSU) shows how immune cells engineered in new cancer therapies can overcome physical barriers so that the patient's own immune system can fight tumors. This research could improve the future of millions of cancer patients worldwide. Immunotherapy, instead of using chemicals or radiation, is a type of cancer treatment that helps the patient's immune system fight cancer. T cells are a type of white blood cell that is essential for the body's immune system. Cytotoxic T cells are like soldiers searching for and destroying target invading cells. Although there has been success in using immunotherapy for some types of cancer in the blood or blood-producing organs, T cell work is much more difficult in solid tumors. Keywords: Cancer; Cells; Tissues, Tumors; Prevention, Prognosis; Diagnosis; Imaging; Screening; Treatment; Management

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