Signaling function of PRC2 is essential for TCR-driven T cell responses

Differentiation and activation of T cells require the activity of numerous histone lysine methyltransferases (HMT) that control the transcriptional T cell output. One of the most potent regulators of T cell differentiation is the HMT Ezh2. Ezh2 is a key enzymatic component of polycomb repressive complex 2 (PRC2), which silences gene expression by histone H3 di/tri-methylation at lysine 27. Surprisingly, in many cell types, including T cells, Ezh2 is localized in both the nucleus and the cytosol. Here we show the presence of a nuclear-like PRC2 complex in T cell cytosol and demonstrate a role of cytosolic PRC2 in T cell antigen receptor (TCR)–mediated signaling. We show that short-term suppression of PRC2 precludes TCR-driven T cell activation in vitro. We also demonstrate that pharmacological inhibition of PRC2 in vivo greatly attenuates the severe T cell–driven autoimmunity caused by regulatory T cell depletion. Our data reveal cytoplasmic PRC2 is one of the most potent regulators of T cell activation and point toward the therapeutic potential of PRC2 inhibitors for the treatment of T cell–driven autoimmune diseases.

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Melanoma-reactive TCR-modified T Cells Generated in the Absence of Activation Retain a Less-differentiated Phenotype and Have Increased Therapeutic Potential.

10.21203/rs.3.rs-238261/v1 ◽

2021 ◽

Author(s):

Siao-Yi Wang ◽

Tamson V. Moore ◽

Annika V. Dalheim ◽

Gina M. Scurti ◽

Michael I. Nishimura

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Viral Vectors ◽

Cell Activation ◽

Therapeutic Potential ◽

Adoptive T Cell Therapy ◽

T Cell Therapy

Abstract Adoptive T cell therapy with T cell receptor (TCR)-modified T cells has shown promise in treating metastatic melanoma and other malignancies. However, studies are needed to improve the efficacy and durability of responses of TCR-modified T cells. Standard protocols for generating TCR-modified T cells involve activating T cells through CD3 stimulation to allow for the efficient transfer of tumor-reactive receptors with viral vectors. T cell activation results in terminal differentiation and shortening of telomeres, which are likely suboptimal for therapy. In these studies, we demonstrate efficient T cell transduction with the melanoma-reactive TIL1383I TCR through culturing with interleukin 7 (IL-7) in the absence of CD3 activation. The TIL1383I TCR-modified T cells generated following IL-7 culture were enriched with naïve (TN) and memory stem cell populations (TSCM) while maintaining longer telomere lengths. Furthermore, we demonstrated melanoma-reactivity of TIL1383I TCR-modified cells generated following IL-7 culture using in vitro assays and a superior response in an in vivo melanoma model. These results suggest that utilizing IL-7 to generate TCR-modified T cells in the absence of activation is a feasible strategy to improve adoptive T cell therapies for melanoma and other malignancies.

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Oral Administration of Liquiritigenin Confers Protection from Atopic Dermatitis through the Inhibition of T Cell Activation

Biomolecules ◽

10.3390/biom10050786 ◽

2020 ◽

Vol 10 (5) ◽

pp. 786

Author(s):

Hyun-Su Lee ◽

Eun-Nam Kim ◽

Gil-Saeng Jeong

Keyword(s):

T Cells ◽

Atopic Dermatitis ◽

T Cell ◽

Oral Administration ◽

T Cell Activation ◽

Cell Activation ◽

Therapeutic Potential ◽

Activated T Cells

While liquiritigenin, isolated from Spatholobus suberectus Dunn, is known to possess anti-inflammatory activities, it still remains to be known whether liquiritigenin has a suppressive effect on T cell activation and T cell-mediated disease. Here, we used Jurkat T cells to explore an underlying mechanism of pre-treatment with liquiritigenin in activated T cell in vitro and used atopic dermatitis (AD) in vivo to confirm it. We found liquiritigenin blocks IL-2 and CD69 expression from activated T cells by PMA/A23187 or anti-CD3/CD28 antibodies. The expressions of surface molecules, including CD40L and CD25, were also reduced in activated T cells pre-treated with liquiritigenin. Western blot analysis indicated repressive effects by liquiritigenin are involved in NFκB and MAPK pathways. To assess the effects of liquiritigenin in vivo, an AD model was applied as T cell-mediated disease. Oral administration of liquiritigenin attenuates AD manifestations, including ear thickness, IgE level, and thicknesses of dermis and epidermis. Systemic protections by liquiritigenin were observed to be declined in size and weight of draining lymph nodes (dLNs) and expressions of effector cytokines from CD4+ T cells in dLNs. These results suggest liquiritigenin has an anti-atopic effect via control of T cell activation and exhibits therapeutic potential for T cell-mediated disorders.

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TRPM2 Is Not Required for T-Cell Activation and Differentiation

Frontiers in Immunology ◽

10.3389/fimmu.2021.778916 ◽

2022 ◽

Vol 12 ◽

Author(s):

Niels C. Lory ◽

Mikolaj Nawrocki ◽

Martina Corazza ◽

Joanna Schmid ◽

Valéa Schumacher ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Transient Receptor Potential ◽

Cell Function ◽

Intestinal Inflammation ◽

Activation Markers

Antigen recognition by the T-cell receptor induces a cytosolic Ca2+ signal that is crucial for T-cell function. The Ca2+ channel TRPM2 (transient receptor potential cation channel subfamily M member 2) has been shown to facilitate influx of extracellular Ca2+ through the plasma membrane of T cells. Therefore, it was suggested that TRPM2 is involved in T-cell activation and differentiation. However, these results are largely derived from in vitro studies using T-cell lines and non-physiologic means of TRPM2 activation. Thus, the relevance of TRPM2-mediated Ca2+ signaling in T cells remains unclear. Here, we use TRPM2-deficient mice to investigate the function of TRPM2 in T-cell activation and differentiation. In response to TCR stimulation in vitro, Trpm2-/- and WT CD4+ and CD8+ T cells similarly upregulated the early activation markers NUR77, IRF4, and CD69. We also observed regular proliferation of Trpm2-/- CD8+ T cells and unimpaired differentiation of CD4+ T cells into Th1, Th17, and Treg cells under specific polarizing conditions. In vivo, Trpm2-/- and WT CD8+ T cells showed equal specific responses to Listeria monocytogenes after infection of WT and Trpm2-/- mice and after transfer of WT and Trpm2-/- CD8+ T cells into infected recipients. CD4+ T-cell responses were investigated in the model of anti-CD3 mAb-induced intestinal inflammation, which allows analysis of Th1, Th17, Treg, and Tr1-cell differentiation. Here again, we detected similar responses of WT and Trpm2-/- CD4+ T cells. In conclusion, our results argue against a major function of TRPM2 in T-cell activation and differentiation.

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Modulating p56Lck in T-Cells by a Chimeric Peptide Comprising Two Functionally Different Motifs of Tip fromHerpesvirus saimiri

Journal of Immunology Research ◽

10.1155/2015/395371 ◽

2015 ◽

Vol 2015 ◽

pp. 1-12

Author(s):

Jean-Paul Vernot ◽

Ana María Perdomo-Arciniegas ◽

Luis Alberto Pérez-Quintero ◽

Diego Fernando Martínez

Keyword(s):

T Cells ◽

T Cell ◽

Lipid Rafts ◽

T Cell Activation ◽

Cell Activation ◽

Jurkat Cells ◽

Chimeric Peptide ◽

Vector Targeting

The Lck interacting protein Tip ofHerpesvirus saimiriis responsible for T-cell transformation bothin vitroandin vivo. Here we designed the chimeric peptide hTip-CSKH, comprising the Lck specific interacting motif CSKH of Tip and its hydrophobic transmembrane sequence (hTip), the latter as a vector targeting lipid rafts. We found that hTip-CSKH can induce a fivefold increase in proliferation of human andAotussp. T-cells. Costimulation with PMA did not enhance this proliferation rate, suggesting that hTip-CSKH is sufficient and independent of further PKC stimulation. We also found that human Lck phosphorylation was increased earlier after stimulation when T-cells were incubated previously with hTip-CSKH, supporting a strong signalling and proliferative effect of the chimeric peptide. Additionally, Lck downstream signalling was evident with hTip-CSKH but not with control peptides. Importantly, hTip-CSKH could be identified in heavy lipid rafts membrane fractions, a compartment where important T-cell signalling molecules (LAT, Ras, and Lck) are present during T-cell activation. Interestingly, hTip-CSKH was inhibitory to Jurkat cells, in total agreement with the different signalling pathways and activation requirements of this leukemic cell line. These results provide the basis for the development of new compounds capable of modulating therapeutic targets present in lipid rafts.

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T cell-T cell activation in multiple sclerosis

Multiple Sclerosis Journal ◽

10.1177/135245859700300404 ◽

1997 ◽

Vol 3 (4) ◽

pp. 238-242 ◽

Cited By ~ 7

Author(s):

JW Lindsey ◽

RH Kerman ◽

JS Wolinsky

Keyword(s):

Multiple Sclerosis ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Viral Infections ◽

Activated T Cells ◽

In Vitro Proliferation

Activated T cells are able to stimulate proliferation in resting T cells through an antigen non-specific mechanism. The in vivo usefulness of this T cell-T cell activation is unclear, but it may serve to amplify immune responses. T cell-T cell activation could be involved in the well-documented occurrence of multiple sclerosis (MS) exacerbations following viral infections. Excessive activation via this pathway could also be a factor in the etiology of MS. We tested the hypothesis that excessive T cell-T cell activation occurs in MS patients using in vitro proliferation assays comparing T cells from MS patients to T cells from controls. When tested as responder cells, T cells from MS patients proliferated slightly less after stimulation with previously activated cells than T cells from controls. When tested as stimulator cells, activated cells from MS patients stimulated slightly more non-specific proliferation than activated cells from controls. Neither of these differences were statistically significant We conclude that T cell proliferation in response to activated T cells is similar in MS and controls.

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Cd2 Sets Quantitative Thresholds in T Cell Activation

Journal of Experimental Medicine ◽

10.1084/jem.190.10.1383 ◽

1999 ◽

Vol 190 (10) ◽

pp. 1383-1392 ◽

Cited By ~ 84

Author(s):

Martin F. Bachmann ◽

Marijke Barner ◽

Manfred Kopf

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Dose Response ◽

Response Curve ◽

Cell Activation ◽

Dose Response Curve ◽

Lymphocyte Function

It has been proposed that CD2, which is highly expressed on T cells, serves to enhance T cell–antigen presenting cell (APC) adhesion and costimulate T cell activation. Here we analyzed the role of CD2 using CD2-deficient mice crossed with transgenic mice expressing a T cell receptor specific for lymphocytic choriomeningitis virus (LCMV)-derived peptide p33. We found that absence of CD2 on T cells shifted the p33-specific dose–response curve in vitro by a factor of 3–10. In comparison, stimulation of T cells in the absence of lymphocyte function–associated antigen (LFA)-1–intercellular adhesion molecule (ICAM)-1 interaction shifted the dose–response curve by a factor of 10, whereas absence of both CD2–CD48 and LFA-1–ICAM-1 interactions shifted the response by a factor of ∼100. This indicates that CD2 and LFA-1 facilitate T cell activation additively. T cell activation at low antigen density was blocked at its very first steps, as T cell APC conjugate formation, TCR triggering, and Ca2+ fluxes were affected by the absence of CD2. In vivo, LCMV-specific, CD2-deficient T cells proliferated normally upon infection with live virus but responded in a reduced fashion upon cross-priming. Thus, CD2 sets quantitative thresholds and fine-tunes T cell activation both in vitro and in vivo.

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In Vivo Detection of Dendritic Cell Antigen Presentation to CD4+ T Cells

Journal of Experimental Medicine ◽

10.1084/jem.185.12.2133 ◽

1997 ◽

Vol 185 (12) ◽

pp. 2133-2141 ◽

Cited By ~ 380

Author(s):

Elizabeth Ingulli ◽

Anna Mondino ◽

Alexander Khoruts ◽

Marc K. Jenkins

Keyword(s):

T Cells ◽

T Cell ◽

Lymph Nodes ◽

T Cell Activation ◽

Cd4 T Cells ◽

Cell Activation ◽

Delayed Type Hypersensitivity ◽

Physical Interaction

Although lymphoid dendritic cells (DC) are thought to play an essential role in T cell activation, the initial physical interaction between antigen-bearing DC and antigen-specific T cells has never been directly observed in vivo under conditions where the specificity of the responding T cells for the relevant antigen could be unambiguously assessed. We used confocal microscopy to track the in vivo location of fluorescent dye-labeled DC and naive TCR transgenic CD4+ T cells specific for an OVA peptide–I-Ad complex after adoptive transfer into syngeneic recipients. DC that were not exposed to the OVA peptide, homed to the paracortical regions of the lymph nodes but did not interact with the OVA peptide-specific T cells. In contrast, the OVA peptide-specific T cells formed large clusters around paracortical DC that were pulsed in vitro with the OVA peptide before injection. Interactions were also observed between paracortical DC of the recipient and OVA peptide-specific T cells after administration of intact OVA. Injection of OVA peptide-pulsed DC caused the specific T cells to produce IL-2 in vivo, proliferate, and differentiate into effector cells capable of causing a delayed-type hypersensitivity reaction. Surprisingly, by 48 h after injection, OVA peptide-pulsed, but not unpulsed DC disappeared from the lymph nodes of mice that contained the transferred TCR transgenic population. These results demonstrate that antigen-bearing DC directly interact with naive antigen-specific T cells within the T cell–rich regions of lymph nodes. This interaction results in T cell activation and disappearance of the DC.

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Type I Interferon-mediated Stimulation of T Cells by CpG DNA

Journal of Experimental Medicine ◽

10.1084/jem.188.12.2335 ◽

1998 ◽

Vol 188 (12) ◽

pp. 2335-2342 ◽

Cited By ~ 271

Author(s):

Siquan Sun ◽

Xiaohong Zhang ◽

David F. Tough ◽

Jonathan Sprent

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Type I Interferons ◽

Type I ◽

Cpg Dna ◽

Stimulation Of

Immunostimulatory DNA and oligodeoxynucleotides containing unmethylated CpG motifs (CpG DNA) are strongly stimulatory for B cells and antigen-presenting cells (APCs). We report here that, as manifested by CD69 and B7-2 upregulation, CpG DNA also induces partial activation of T cells, including naive-phenotype T cells, both in vivo and in vitro. Under in vitro conditions, CpG DNA caused activation of T cells in spleen cell suspensions but failed to stimulate highly purified T cells unless these cells were supplemented with APCs. Three lines of evidence suggested that APC-dependent stimulation of T cells by CpG DNA was mediated by type I interferons (IFN-I). First, T cell activation by CpG DNA was undetectable in IFN-IR−/− mice. Second, in contrast to normal T cells, the failure of purified IFN-IR−/− T cells to respond to CpG DNA could not be overcome by adding normal IFN-IR+ APCs. Third, IFN-I (but not IFN-γ) caused the same pattern of partial T cell activation as CpG DNA. Significantly, T cell activation by IFN-I was APC independent. Thus, CpG DNA appeared to stimulate T cells by inducing APCs to synthesize IFN-I, which then acted directly on T cells via IFN-IR. Functional studies suggested that activation of T cells by IFN-I was inhibitory. Thus, exposing normal (but not IFN-IR−/−) T cells to CpG DNA in vivo led to reduced T proliferative responses after TCR ligation in vitro.

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Humulus scandens Exhibits Immunosuppressive Effects in Vitro and in Vivo by Suppressing CD4+ T Cell Activation

The American Journal of Chinese Medicine ◽

10.1142/s0192415x1450058x ◽

2014 ◽

Vol 42 (04) ◽

pp. 921-934 ◽

Cited By ~ 2

Author(s):

Jinjin Feng ◽

Yingchun Wu ◽

Yang Yang ◽

Weiqi Jiang ◽

Shaoping Hu ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Activation ◽

Interferon Γ ◽

Delayed Type Hypersensitivity ◽

Ifn Γ ◽

Humulus Scandens

Humulus scandens, rich in flavonoids, is a traditional Chinese medicine. It is widely used in China to treat tuberculosis, dysentery and chronic colitis. In this study, the major active faction of Humulus scandens (H.S) was prepared. Then, its immunosuppressive effects and underlying mechanisms on T cell activation were investigated in vitro and in vivo. Results showed that H.S significantly inhibited the proliferation of splenocytes induced by concanavalin A, lipopolysaccharides, and mixed-lymphocyte reaction in vitro. Additionally, H.S could dramatically suppress the proliferation and interferon-γ (IFN-γ) production from T cells stimulated by anti-CD3 and anti-CD28. Flow cytometric results confirmed that H.S could suppress the differentiation of IFN-γ-producing type 1 helper T cells (Th1). Furthermore, using ovalbumin immunization-induced T cell reaction and CD4+ T-cell-mediated delayed type hypersensitivity reaction, H.S the immunosuppressive effects of H.S was also demonstrated in vivo. Western blot results showed that H.S could impede the activation of both Erk1/2 and P38 in primary T cells triggered by anti-CD3/28. Collectively, the active fraction of H.S showed promising immunosuppressive activities both in vitro and in vivo.

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Bacterial Pathogens Induce Abscess Formation by CD4+ T-Cell Activation via the CD28–B7-2 Costimulatory Pathway

Infection and Immunity ◽

10.1128/iai.68.12.6650-6655.2000 ◽

2000 ◽

Vol 68 (12) ◽

pp. 6650-6655 ◽

Cited By ~ 37

Author(s):

Arthur O. Tzianabos ◽

Anil Chandraker ◽

Wiltrud Kalka-Moll ◽

Francesca Stingele ◽

Victor M. Dong ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Pathogenic Bacteria ◽

Cell Activation ◽

Bacterial Pathogens ◽

Abscess Formation

ABSTRACT Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naı̈ve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus,Bacteroides fragilis, and a combination ofEnterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28–B7-2 pathway.

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