Anti-Thy-1-mediated T cell activation. Role of soluble factors and expression of interleukin 2 receptors on T cells

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.

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

Journal of Experimental Medicine ◽

10.1084/jem.177.6.1791 ◽

1993 ◽

Vol 177 (6) ◽

pp. 1791-1796 ◽

Cited By ~ 182

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.

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In Vivo Role of Dendritic Cells in a Murine Model of Pulmonary Cryptococcosis

Infection and Immunity ◽

10.1128/iai.00317-06 ◽

2006 ◽

Vol 74 (7) ◽

pp. 3817-3824 ◽

Cited By ~ 58

Author(s):

Karen L. Wozniak ◽

Jatin M. Vyas ◽

Stuart M. Levitz

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell Activation ◽

Cell Activation ◽

Ex Vivo ◽

Interleukin 2 ◽

Mouse Lung

ABSTRACT Dendritic cells (DC) have been shown to phagocytose and kill Cryptococcus neoformans in vitro and are believed to be important for inducing protective immunity against this organism. Exposure to C. neoformans occurs mainly by inhalation, and in this study we examined the in vivo interactions of C. neoformans with DC in the lung. Fluorescently labeled live C. neoformans and heat-killed C. neoformans were administered intranasally to C57BL/6 mice. At specific times postinoculation, mice were sacrificed, and lungs were removed. Single-cell suspensions of lung cells were prepared, stained, and analyzed by microscopy and flow cytometry. Within 2 h postinoculation, fluorescently labeled C. neoformans had been internalized by DC, macrophages, and neutrophils in the mouse lung. Additionally, lung DC from mice infected for 7 days showed increased expression of the maturation markers CD80, CD86, and major histocompatibility complex class II. Finally, ex vivo incubation of lung DC from infected mice with Cryptococcus-specific T cells resulted in increased interleukin-2 production compared to the production by DC from naïve mice, suggesting that there was antigen-specific T-cell activation. This study demonstrated that DC in the lung are capable of phagocytosing Cryptococcus in vivo and presenting antigen to C. neoformans-specific T cells ex vivo, suggesting that these cells have roles in innate and adaptive pulmonary defenses against cryptococcosis.

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Isolevuglandin-Modified Cardiac Proteins Drive CD4+ T Cell Activation in the Heart and Promote Cardiac Dysfunction

Circulation ◽

10.1161/circulationaha.120.051889 ◽

2021 ◽

Author(s):

Njabulo Ngwenyama ◽

Annet Kirabo ◽

Mark Aronovitz ◽

Francisco Velázquez ◽

Francisco Carrillo-Salinas ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Antigen Presentation ◽

T Cell Activation ◽

Cardiac Dysfunction ◽

Cd4 T Cells ◽

Cell Activation ◽

Cd4 T Cell ◽

Myocardial Oxidative Stress

Background: Despite the well-established association between T cell-mediated inflammation and non-ischemic heart failure (HF), the specific mechanisms triggering T cell activation during the progression of HF and the antigens involved are poorly understood. We hypothesized that myocardial oxidative stress induces the formation of isolevuglandin (IsoLG)-modified proteins that function as cardiac neoantigens to elicit CD4+ T cell receptor (TCR) activation and promote HF. Methods: We used transverse aortic constriction (TAC) in mice to trigger myocardial oxidative stress and T cell infiltration. We profiled the TCR repertoire by mRNA sequencing of intramyocardial activated CD4+ T cells in Nur77 GFP reporter mice, which transiently express GFP upon TCR engagement. We assessed the role of antigen presentation and TCR specificity in the development of cardiac dysfunction using antigen presentation-deficient MhcII -/- mice, and TCR transgenic OTII mice that lack specificity for endogenous antigens. We detected IsoLG-protein adducts in failing human hearts. We also evaluated the role of reactive oxygen species (ROS) and IsoLGs in eliciting T cell immune responses in vivo by treating mice with the antioxidant TEMPOL, and the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) during TAC, and ex-vivo in mechanistic studies of CD4+ T cell proliferation in response to IsoLG-modified cardiac proteins. Results: We discovered that TCR antigen recognition increases in the left ventricle (LV) as cardiac dysfunction progresses, and identified a limited repertoire of activated CD4+ T cell clonotypes in the LV. Antigen presentation of endogenous antigens was required to develop cardiac dysfunction since MhcII -/- mice reconstituted with CD4+ T cells, and OTII mice immunized with their cognate antigen were protected from TAC-induced cardiac dysfunction despite the presence of LV-infiltrated CD4+ T cells. Scavenging IsoLGs with 2-HOBA reduced TCR activation and prevented cardiac dysfunction. Mechanistically, cardiac pressure overload resulted in ROS dependent dendritic cell accumulation of IsoLG-protein adducts which induced robust CD4+ T cell proliferation. Conclusions: Collectively, our study demonstrates an important role of ROS-induced formation of IsoLG-modified cardiac neoantigens that lead to TCR-dependent CD4+ T cell activation within the heart.

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SLFN2 protection of tRNAs from stress-induced cleavage is essential for T cell–mediated immunity

Science ◽

10.1126/science.aba4220 ◽

2021 ◽

Vol 372 (6543) ◽

pp. eaba4220 ◽

Cited By ~ 1

Author(s):

Tao Yue ◽

Xiaoming Zhan ◽

Duanwu Zhang ◽

Ruchi Jain ◽

Kuan-wen Wang ◽

...

Keyword(s):

Oxidative Stress ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Interleukin 2 ◽

Cell Receptor ◽

Cell Mediated Immunity ◽

Activated T Cells ◽

Granule Formation

Reactive oxygen species (ROS) increase in activated T cells because of metabolic activity induced to support T cell proliferation and differentiation. We show that these ROS trigger an oxidative stress response that leads to translation repression. This response is countered by Schlafen 2 (SLFN2), which directly binds transfer RNAs (tRNAs) to protect them from cleavage by the ribonuclease angiogenin. T cell–specific SLFN2 deficiency results in the accumulation of tRNA fragments, which inhibit translation and promote stress-granule formation. Interleukin-2 receptor β (IL-2Rβ) and IL-2Rγ fail to be translationally up-regulated after T cell receptor stimulation, rendering SLFN2-deficient T cells insensitive to interleukin-2’s mitogenic effects. SLFN2 confers resistance against the ROS-mediated translation-inhibitory effects of oxidative stress normally induced by T cell activation, permitting the robust protein synthesis necessary for T cell expansion and immunity.

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Antigen-independent activation of naive and memory resting T cells by a cytokine combination.

Journal of Experimental Medicine ◽

10.1084/jem.180.3.1159 ◽

1994 ◽

Vol 180 (3) ◽

pp. 1159-1164 ◽

Cited By ~ 238

Author(s):

D Unutmaz ◽

P Pileri ◽

S Abrignani

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Interleukin 2 ◽

Effector Function ◽

Necrosis Factor Alpha ◽

Naive T Cells ◽

Naïve T Cells

We investigated whether human resting T cells could be activated to proliferate and display effector function in the absence of T cell receptor occupancy. We report that combination of interleukin 2 (IL-2), tumor necrosis factor alpha, and IL-6 activated highly purified naive (CD45RA+) and memory (CD45RO+) resting CD4+ T cells to proliferate. Under this condition, memory resting T cells could also display effector function as measured by lymphokine synthesis and help for immunoglobulin production by B cells. This novel Ag-independent pathway of T cell activation may play an important role in vivo in recruiting effector T cells at the site of immune response and in maintaining the clonal size of memory T cells in the absence of antigenic stimulation. Moreover, cytokines can induce proliferation of naive T cells without switch to memory phenotype and this may help the maintenance of the peripheral pool of naive T cells.

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Effect of CD28 signal transduction on c-Rel in human peripheral blood T cells

Molecular and Cellular Biology ◽

10.1128/mcb.14.12.7933-7942.1994 ◽

1994 ◽

Vol 14 (12) ◽

pp. 7933-7942

Author(s):

R G Bryan ◽

Y Li ◽

J H Lai ◽

M Van ◽

N R Rice ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Peripheral Blood ◽

Cell Activation ◽

Nuclear Translocation ◽

Human Peripheral Blood ◽

Interleukin 2 ◽

Cell Receptor ◽

Cd28 Costimulation

Optimal T-cell activation requires both an antigen-specific signal delivered through the T-cell receptor and a costimulatory signal which can be delivered through the CD28 molecule. CD28 costimulation induces the expression of multiple lymphokines, including interleukin 2 (IL-2). Because the c-Rel transcription factor bound to and activated the CD28 response element within the IL-2 promoter, we focused our study on the mechanism of CD28-mediated regulation of c-Rel in human peripheral blood T cells. We showed that CD28 costimulation accelerated the kinetics of nuclear translocation of c-Rel (and its phosphorylated form), p50 (NFKB1), and p65 (RelA). The enhanced nuclear translocation of c-Rel correlated with the stimulation of Il-2 production and T-cell proliferation by several distinct anti-CD28 monoclonal antibodies. This is explained at least in part by the long-term downregulation of I kappa B alpha following CD28 signalling as opposed to phorbol myristate acetate alone. Furthermore, we showed that the c-Rel-containing CD28-responsive complex is enhanced by, but not specific to, CD28 costimulation. Our results indicate that c-Rel is one of the transcription factors targeted by CD28 signalling.

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Diacylglycerol kinase ζ limits IL-2-dependent control of PD-1 expression in tumor-infiltrating T lymphocytes

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-001521 ◽

2020 ◽

Vol 8 (2) ◽

pp. e001521

Author(s):

Javier Arranz-Nicolás ◽

Miguel Martin-Salgado ◽

Cristina Rodríguez-Rodríguez ◽

Rosa Liébana ◽

Maria C Moreno-Ortiz ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Therapeutic Potential ◽

Interleukin 2 ◽

Tumor Rejection ◽

Cytotoxic T Cell ◽

Adenocarcinoma Cells ◽

The Impact

BackgroundThe inhibitory functions triggered by the programmed cell death-1 (PD-1) receptor following binding to its ligand (PD-L1) protect healthy organs from cytotoxic T cells, and neutralize antitumor T cell attack. Antibody-based therapies to block PD-1/PD-L1 interaction have yielded notable results, but most patients eventually develop resistance. This failure is attributed to CD8+ T cells achieving hyporesponsive states from which recovery is hardly feasible. Dysfunctional T cell phenotypes are favored by a sustained imbalance in the diacylglycerol (DAG)- and Ca2+-regulated transcriptional programs. In mice, DAG kinase ζ (DGKζ) facilitates DAG consumption, limiting T cell activation and cytotoxic T cell responses. DGKζ deficiency facilitates tumor rejection in mice without apparent adverse autoimmune effects. Despite its therapeutic potential, little is known about DGKζ function in human T cells, and no known inhibitors target this isoform.MethodsWe used a human triple parameter reporter cell line to examine the consequences of DGKζ depletion on the transcriptional restriction imposed by PD-1 ligation. We studied the effect of DGKζ deficiency on PD-1 expression dynamics, as well as the impact of DGKζ absence on the in vivo growth of MC38 adenocarcinoma cells.ResultsWe demonstrate that DGKζ depletion enhances DAG-regulated transcriptional programs, promoting interleukin-2 production and partially counteracting PD-1 inhibitory functions. DGKζ loss results in limited PD-1 expression and enhanced expansion of cytotoxic CD8+ T cell populations. This is observed even in immunosuppressive milieus, and correlates with the reduced ability of MC38 adenocarcinoma cells to form tumors in DGKζ-deficient mice.ConclusionsOur results, which define a role for DGKζ in the control of PD-1 expression, confirm DGKζ potential as a therapeutic target as well as a biomarker of CD8+ T cell dysfunctional states.

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HIV-specific T-cell Responses and Generalized Activation in HIV-1 Infected Long-term Non-progressors and Progressors from South India

Current HIV Research ◽

10.2174/1570162x17666181212122607 ◽

2019 ◽

Vol 16 (4) ◽

pp. 302-314

Author(s):

Chinnambedu Ravichandran Swathirajan ◽

Ramachandran Vignesh ◽

Greer Waldrop ◽

Uma Shanmugasundaram ◽

Pannerselvam Nandagopal ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Cd4 T Cell ◽

Cell Responses ◽

Activation Rates ◽

Hiv 1

Background:Anti-viral cytokine expressions by cytotoxic T-cells and lower activation rates have been reported to correlate with suppressed HIV replication in long-term non-progressors (LTNP). Immune mechanisms underlying disease non-progression in LTNP might vary with HIV-1 subtype and geographical locations.Objective:This study evaluates cytokine expression and T-cells activation in relation to disease non-progression in LTNP.Methods:HIV-1 Subtype C infected LTNP (n=20) and progressors (n=15) were enrolled and flowcytometry assays were performed to study HIV-specific CD8 T-cells expressing IL-2, IFN-γ, TNF-α and MIP-1β against gag and env peptides. CD4+ T-cell activation was evaluated by surface expression of HLADR and CD38.Results:Proportions of cytokines studied did not differ significantly between LTNP and progressors, while contrasting correlations with disease progression markers were observed in LTNP. CD4+ T-cell activation rates were significantly lower in LTNP compared to progressors which indicate the potential role of T-cell activation rates in disease non-progression in LTNP.Conclusion:LTNP and progressors showed similar CD8+ T-cell responses, but final conclusions can be drawn only by comparing multiple immune factors in larger LTNP cohort with HIV-1 infected individuals at various levels of disease progression. A possible role of HIV-1 subtype variation and ethnic differences in addition to host-genetic and viral factors cannot be ruled out.

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Role of T-cell activation in salt-sensitive hypertension

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00096.2019 ◽

2019 ◽

Vol 316 (6) ◽

pp. H1345-H1353 ◽

Cited By ~ 4

Author(s):

Jiafa Ren ◽

Steven D. Crowley

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Naive T Cells ◽

Naïve T Cells ◽

T Subsets ◽

Underlying Mechanisms ◽

Salt Sensitive Hypertension

The contributions of T lymphocytes to the pathogenesis of salt-sensitive hypertension has been well established. Under hypertensive stimuli, naive T cells develop into different subsets, including Th1, Th2, Th17, Treg, and cytotoxic CD8+ T cells, depending on the surrounding microenviroment in organs. Distinct subsets of T cells may play totally different roles in tissue damage and hypertension. The underlying mechanisms by which hypertensive stimuli activate naive T cells involve many events and different organs, such as neoantigen presentation by dendritic cells, high salt concentration, and the milieu of oxidative stress in the kidney and vasculature. Infiltrating and activated T subsets in injured organs, in turn, exert considerable impacts on tissue dysfunction, including sodium retention in the kidney, vascular stiffness, and remodeling in the vasculature. Therefore, a thorough knowledge of T-cell actions in hypertension may provide novel insights into the development of new therapeutic strategies for patients with hypertension.

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