Effect of RELT on regulation of the threshold of T-cell activation during sterile inflammation.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 25-25
Author(s):  
Seon-Hee Kim ◽  
Beom K. Choi ◽  
Chungyong Han ◽  
Byoung S. Kwon
Keyword(s):  
T Cells ◽  
T Cell ◽  
Liver Injury ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Sterile Inflammation ◽  
Tumor Growth Rate ◽  
Lymphoid Tissues ◽  
Type I

25 Background: Receptor expressed in lymphoid tissue (RELT) is a type I transmembrane protein, designated TNFRSF19-like, and primarily expressed in lymphoid tissues and immune cells. However, its immunological function has yet to be characterized. Methods: We developed RELT-deficient mice to examine the immunological role of RELT. The RELT–/– mice were exposed to viral and bacterial infection, chemical-induced liver injury, and tumor induction. Results: RELT–/– mice were viable and fertile, and developed normal lymphoid and myeloid cells. RELT transcripts were decreased in T cells and dendritic cells following their activation, and T-cell proliferation was enhanced in the absence of RELT in vitro. Nevertheless, we could not find significant changes in RELT–/– mice infected with virus or bacteria. However, liver injury and inflammation were significantly increased in RELT–/– mice in comparison to RELT+/+ mice after the injection of acetaminophen. Tumor growth rate was also slower in RELT–/– than RELT+/+ mice. Transfer of naïve or activated pmel-1 CD8+ T cells suppressed the growth of B16–F10 tumors and increased host CD8+ tumor-infiltrating cells more efficiently in RELT–/– than in RELT+/+ mice. In particular, naïve pmel-1 CD8+ T cells were present in increased numbers and activated forms in draining lymph nodes of RELT–/– than in RELT+/+ mice, whereas activated pmel-1 CD8+ T cells were not. Conclusions: As RELT–/– mice only showed significant differences in comparison to RELT+/+ mice in pathogen-associated-molecular-pattern-free conditions, these results provide evidence that RELT functions as a negative modulator of T cell responses in a sterile inflammation.

The costimulatory activity of Tim-3 requires Akt and MAPK signaling and its recruitment to the immune synapse

2021 ◽  
Vol 14 (687) ◽  
pp. eaba0717
Author(s):  
Shunsuke Kataoka ◽  
Priyanka Manandhar ◽  
Judong Lee ◽  
Creg J. Workman ◽  
Hridesh Banerjee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Domain ◽  
Transmembrane Protein ◽  
Cell Receptor ◽  
Mapk Signaling ◽  
Inhibitory Protein ◽  
Immune Synapse

Expression of the transmembrane protein Tim-3 is increased on dysregulated T cells undergoing chronic activation, including during chronic infection and in solid tumors. Thus, Tim-3 is generally thought of as an inhibitory protein. We and others previously reported that under some circumstances, Tim-3 exerts paradoxical costimulatory activity in T cells (and other cells), including enhancement of the phosphorylation of ribosomal S6 protein. Here, we examined the upstream signaling pathways that control Tim-3–mediated increases in phosphorylated S6 in T cells. We also defined the localization of Tim-3 relative to the T cell immune synapse and its effects on downstream signaling. Recruitment of Tim-3 to the immune synapse was mediated exclusively by the transmembrane domain, replacement of which impaired the ability of Tim-3 to costimulate T cell receptor (TCR)–dependent S6 phosphorylation. Furthermore, enforced localization of the Tim-3 cytoplasmic domain to the immune synapse in a chimeric antigen receptor still enabled T cell activation. Together, our findings are consistent with a model whereby Tim-3 enhances TCR-proximal signaling under acute conditions.

Parasite species regulates T cell activation in human malaria

2021 ◽  
Author(s):  
Florian Bach ◽  
Diana Munoz Sandoval ◽  
Michalina Mazurczyk ◽  
Yrene Themistocleous ◽  
Thomas A Rawlinson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Plasmodium Vivax ◽  
T Cell Activation ◽  
Cell Activation ◽  
Parasite Species ◽  
Field Isolate ◽  
Effector Memory ◽  
Lymphoid Tissues ◽  
Systems Immunology

Plasmodium vivax offers unique challenges for malaria control and may prove a more difficult species to eradicate than Plasmodium falciparum. Yet compared to P. falciparum we know very little about the innate and adaptive immune responses that need to be harnessed to reduce disease and transmission. In this study, we inoculated human volunteers with a clonal field isolate of P. vivax and used systems immunology tools to track their response through infection and convalescence. Our data reveal Plasmodium vivax triggers an acute phase response that shares remarkable overlap with that of P. falciparum, suggesting a hardwired innate response that does not differentiate between parasite species. This leads to the global recruitment of innate-like and adaptive T cells into lymphoid tissues where up to one quarter of the T cell compartment is activated. Heterogeneous effector memory-like CD4+ T cells dominate this response and their activation coincides with collateral tissue damage. Remarkably, comparative transcriptional analyses show that P. falciparum drives even higher levels of T cell activation; diverging T cell responses may therefore explain why falciparum malaria more frequently causes severe disease.

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.

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

1998 ◽  
Vol 188 (12) ◽  
pp. 2335-2342 ◽  
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.

scholarly journals HIV-specific CD8+ T-cells in tonsils express exhaustive TRM-like signatures

2021 ◽  
Author(s):  
Rabiah Fardoos ◽  
Sarah K. Nyquist ◽  
Osaretin E. Asowata ◽  
Samuel W. Kazer ◽  
Alveera Singh ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Ex Vivo ◽  
Cytolytic Activity ◽  
Lymphoid Tissues ◽  
People Living With Hiv ◽  
Natural Immunity

Lymphoid tissues are an important HIV reservoir site that persists in the face of antiretroviral therapy and natural immunity. Targeting these reservoirs by harnessing the antiviral activity of local tissue resident memory (TRM) CD8+ T-cells is of great interest, but limited data exist on TRMs within lymph nodes of people living with HIV (PLWH). Here, we studied tonsil CD8+ T-cells obtained from PLWH and uninfected controls from South Africa. We show that these cells are preferentially located outside the germinal centers (GCs), the main reservoir site for HIV, and display a low cytolytic and transcriptionally TRM-like profile that is distinct from blood. In PLWH, CD8+ TRM-like cells are highly expanded and adopt a more cytolytic, activated and exhausted phenotype characterized by increased expression of CD69, PD-1 and perforin, but reduced CD127. This phenotype was enhanced in HIV-specific CD8+ T-cells from tonsils compared to matched blood. Single-cell profiling of these cells revealed a clear transcriptional signature of T-cell activation, clonal expansion and exhaustion ex-vivo. In contrast, this signature was absent from HIV-specific CD8+ T-cells in tonsils isolated from a natural HIV controller, who expressed lower levels of cell surface PD-1 and CXCR5, and reduced transcriptional evidence of T-cell activation, exhaustion and cytolytic activity. Thus, we show that HIV-specific TRM-like CD8+ T-cells in tonsils from non-HIV controllers are enriched for activation and exhaustion profiles compared to those in blood, suggesting that lymphoid HIV specific CD8+ TRM cells are potentially ideal candidates for immunotherapy to modulate their ability to targeting the HIV reservoirs.

scholarly journals The co-stimulatory activity of Tim-3 requires Akt and MAPK signaling and immune synapse recruitment

2019 ◽  
Author(s):  
Shunsuke Kataoka ◽  
Priyanka Manandhar ◽  
Creg J. Workman ◽  
Hridesh Banerjee ◽  
Andrea L. Szymczak-Workman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Domain ◽  
Transmembrane Protein ◽  
Mapk Signaling ◽  
Immune Synapse ◽  
Downstream Signaling ◽  
Stimulatory Activity

AbstractExpression of the transmembrane protein Tim-3 is increased on dysregulated T cells undergoing chronic T cell activation, including in chronic infection and solid tumors. We and others previously reported that Tim-3 exerts apparently paradoxical co-stimulatory activity in T cells (and other cells), including enhancement of ribosomal S6 protein phosphorylation (pS6). Here we examined the upstream signaling pathways that control Tim3-mediated increases in pS6 in T cells. We have also defined the localization of Tim-3 relative to the T cell immune synapse and impacts on downstream signaling. Recruitment of Tim-3 to the immune synapse was regulated exclusively by the transmembrane domain, replacement of which impaired Tim-3 co-stimulation of pS6. Strikingly, enforced localization of the Tim-3 cytoplasmic domain to the immune synapse in the context of a chimeric antigen receptor still allowed for robust T cell activation. Our findings are consistent with a model whereby Tim-3 enhances TCR-proximal signaling under acute conditions.

scholarly journals Time-Dependent Serial Changes of Antigen-Presenting Cell Subsets in the Ocular Surface Are Distinct between Corneal Sterile Inflammation and Allosensitization in a Murine Model

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2210
Author(s):  
Kyoung-Woo Kim ◽  
Hyun-Ju Lee ◽  
Hyeon-Ji Kim ◽  
Mee-Kum Kim
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Ocular Surface ◽  
Cell Activation ◽  
Corneal Transplantation ◽  
Cell Subset ◽  
Sterile Inflammation ◽  
T Cell Subsets ◽  
Antigen Presenting

The kinetics of antigen-presenting cells (APCs) vary depending on their resident tissues and the manner of immunization. We investigated the long-term changes in mature APC and T-cell subsets over 4 weeks in the ocular surface in murine models of corneal quiescent or potent sterile inflammation, and allosensitization using partial (PT), syngeneic (Syn), and allogeneic (Allo) corneal transplantation. In PT, CD11bintCD11chiMHCIIhiCD86hi cells increased until 4 weeks with an increase in IFNγhi T cells. In Syn, both CD11bintCD11chiMHCIIhiCD86hi and CD11bhiCD11chiMHCIIhiCD86hi APC subsets increased until 4 weeks with a brief increase in CD69hi T cells at 2 weeks. In Allo, CD11bintCD11chiMHCIIhiCD86hi and CD11bhiCD11chiMHCIIhiCD86hi APC subsets increased until 4 weeks, and an early increase in CD69hi T cells was observed at 2 weeks followed by a late increase in IFNγhi T cells at 4 weeks. The frequency of the IFNγhi T cell subset was positively correlated with the frequency of the CD11bintCD11chiMHCIIhiCD86hi subset, indicating the existence of APC–T cell interaction in the ocular surface. Together, the results indicate that allosensitization in mature APCs leads to T-cell activation in the ocular surface, whereas sterile inflammation merely induces a brief and non-specific T-cell activation in the ocular surface.

scholarly journals Type I Interferon Signaling before Hematopoietic Stem Cell Transplantation Lowers Donor T Cell Activation Via Reduced Allogenicity of Recipient Cells

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4431-4431
Author(s):  
Erik Thiele Orberg ◽  
Julius Clemens Fischer ◽  
Sascha Göttert ◽  
Florian Bassermann ◽  
Hendrik Poeck
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
T Cell Activation ◽  
Cell Activation ◽  
Type I ◽  
Hematopoietic Stem ◽  
Conditioning Therapy

Background: Recent studies highlight immunoregulatory functions of type I interferons (IFN-I) during the pathogenesis of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We demonstrated that selective activation of IFN-I pathways including RIG-I/MAVS and cGAS/STING prior to allo-HSCT conditioning therapy can ameliorate the course of GVHD. However, direct effects of IFN-Is on immune cells remain ill characterised. Methods: We applied selective RIG-I agonists (3pRNA) to stimulate IFN-I production in murine models of conditioning therapy with total body irradiation (TBI) and GVHD. Results: Using IFNAR1-deficient donor T and hematopoietic donor cells, we found that endogenous and RIG-I-induced IFN-Is do not reduce GVHD by acting on these respective cell types. However, 3pRNA applied before conditioning therapy reduced the ability of CD11c+ recipient cells to stimulate proliferation and interferon gamma expression of allogeneic T cells. Consistently, RIG-I activation before TBI reduced the proliferation of transplanted T-cells after allo-HSCT. The reduced allogenicity of CD11c+ recipient cells was dependent on IFN-I signalling. Notably, this immunosuppressive function of DCs was restricted to a scenario of genotoxic tissue damage as neither RIG-I activation and IFN-I induction in naive (non-irradiated) mice altered allogeneic T cell activation. Conclusion: Our findings uncover a hitherto unknown IFN-I- and context dependent immunosuppressive function of dendritic cells. This needs to be considered in the development of IFN-I based therapeutic approaches to modulate donor T cell activation after allo-HSCT. Disclosures No relevant conflicts of interest to declare.

scholarly journals Discovery of Novel Inhibitors From Medicinal Plants for V-Domain Ig Suppressor of T-Cell Activation

2021 ◽  
Vol 8 ◽  
Author(s):  
Iqra Muneer ◽  
Sajjad Ahmad ◽  
Anam Naz ◽  
Sumra Wajid Abbasi ◽  
Adel Alblihy ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Transmembrane Protein ◽  
Experimental Studies ◽  
Binding Energies ◽  
Type I ◽  
Active Site Residues ◽  
High Concentration ◽  
Delay Tumor Growth

V-domain Ig suppressor of T cell activation (VISTA) is an immune checkpoint and is a type I transmembrane protein. VISTA is linked to immunotherapy resistance, and it is a potential immune therapeutic target, especially for triple-negative breast cancer. It expresses at a high concentration in regulatory T cells and myeloid-derived suppressor cells, and its functional blockade is found to delay tumor growth. A useful medicinal plant database for drug designing (MPD3), which is a collection of phytochemicals from diverse plant families, was employed in virtual screening against VISTA to prioritize natural inhibitors against VISTA. Three compounds, Paratocarpin K (PubChem ID: 14187087), 3-(1H-Indol-3-yl)-2-(trimethylazaniumyl)propanoate (PubChem ID: 3861164), and 2-[(5-Benzyl-4-ethyl-1,2,4-triazol-3-yl)sulfanylmethyl]-5-methyl-1,3,4-oxadiazole (PubChem ID: 6494266), having binding energies stronger than −6 kcal/mol were found to have two common hydrogen bond interactions with VISTA active site residues: Arg54 and Arg127. The dynamics of the compound–VISTA complexes were further explored to infer binding stability of the systems. Results revealed that the compound 14187087 and 6494266 systems are highly stable with an average RMSD of 1.31 Å. Further affirmation on the results was achieved by running MM-GBSA on the MD simulation trajectories, which re-ranked 14187087 as the top-binder with a net binding energy value of −33.33 kcal/mol. In conclusion, the present study successfully predicted natural compounds that have the potential to block the function of VISTA and therefore can be utilized further in experimental studies to validate their real anti-VISTA activity.

Secondary Lymphoid Tissues Are Not Required for the Induction of GVHD Following Allogeneic BMT: A Shifting Paradigm for T Cell Allo-Activation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3170-3170
Author(s):  
Ines A. Silva ◽  
Krystyna Olkiewicz ◽  
Jacquelyn M. Fisher ◽  
Meghana N. Chaudhary ◽  
Kevin Vannella Vannella ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Major Complication ◽  
Scoring Systems ◽  
Lymphoid Tissues ◽  
Target Tissue

Abstract Allogeneic (allo) bone marrow transplantation (BMT) is the only curative option for many patients with malignant and non-malignant diseases. Acute graft versus host disease (GVHD) is the major complication of allo-BMT and limits the utility of this treatment strategy. The induction of GVHD fundamentally depends upon the activation of donor T cells by host antigen presenting cells (APCs), and the prevailing hypothesis is that these critical interactions occur in secondary lymphoid organs, such as lymph nodes (LN) Peyer’s patches (PP), and spleen (SP). We tested this hypothesis by using a well established, MHC disparate, murine SCT system (Balb/c → B6) and homozygous aly/aly (alymphoplasia) mice that are deficient in all LN and PP and heterozygous aly/+ littermate controls. Lethally irradiated, splenectomized, aly/aly mice (LN/PP/SP −/ −) and aly/+ sham mice (LN/PP/SP +/+) received BMT either from syngeneic (aly/aly) or allo (Balb/c) donors. In some experiments, wild-type B6 recipients of B6 or Balb/c BMT served as additional negative and positive GVHD controls respectively. The severity of GVHD was assessed by survival and well-described scoring systems of both clinical and target organ disease. As expected, greater than 95% of syngeneic (syn) BMT recipients survived and were indistinguishable from naïve, un-transplanted controls, whereas LN/PP/SP +/+ mice receiving allo-BMT showed significant signs of GVHD with ~40% mortality by day 49. All LN/PP/SP −/ − allo-BMT recipients also survived, but surprisingly, examination demonstrated that they too developed significant clinical GVHD compared to syn controls (score: 3.2 vs. 0.85) that was comparable in severity to LN/PP/SP +/+ mice (3.1). Moreover, histopathologic analysis demonstrated that LN/PP/SP −/ − allo-BMT recipients developed significantly greater GVHD target tissue damage in the liver, intestinal tract and skin compared to syn controls. In fact, LN/PP/SP −/ − allo-BMT recipients developed more severe hepatic GVHD compared to allo littermate (LN/PP/SP +/+) controls (30.8±1.9 vs. 20.7±2.2; p < 0.01). Similar differences in liver GVHD was also seen between allo groups as early as day 7 (16.0±2.2 vs. 7.3±0.9; p < 0.01). We next tested the ability of host aly/aly and aly/+ APCs to stimulate donor Balb/c T cells in vitro. No differences in proliferation, IFN γ production or CTL generation were detected, thus showing that the allo-stimulatory capacity of host APCs was not different between groups. In order to ascertain what extra-lymphoid host tissues might serve as initial sites for allo-antigen exposure, we examined donor T cell expansion (CD3+), activation (CD69+) and proliferation (CFSE) in the bone marrow compartment 3 days after BMT. We found that in each case, LN/PP/SP −/ − allo-BMT recipients had significantly higher numbers / divisions compared to allo, littermate, (LN/PP/SP +/+) controls. Collectively, these data challenge the paradigm that secondary lymphoid tissues are required for GVHD induction, and suggest that the bone marrow may represent an alternative site for allo-antigen recognition and donor T cell activation.

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