scholarly journals Cytomegalovirus inhibition of extrinsic apoptosis determines fitness and resistance to cytotoxic CD8 T cells

2020 ◽  
Vol 117 (23) ◽  
pp. 12961-12968 ◽  
Author(s):  
M. Zeeshan Chaudhry ◽  
Rosaely Casalegno-Garduno ◽  
Katarzyna M. Sitnik ◽  
Bahram Kasmapour ◽  
Ann-Kathrin Pulm ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Death Receptor ◽  
Cd8 T Cell ◽  
Cytotoxic T Cell ◽  
Caspase 8 ◽  
Infected Cells

Viral immune evasion is currently understood to focus on deflecting CD8 T cell recognition of infected cells by disrupting antigen presentation pathways. We evaluated viral interference with the ultimate step in cytotoxic T cell function, the death of infected cells. The viral inhibitor of caspase-8 activation (vICA) conserved in human cytomegalovirus (HCMV) and murine CMV (MCMV) prevents the activation of caspase-8 and proapoptotic signaling. We demonstrate the key role of vICA from either virus, in deflecting antigen-specific CD8 T cell-killing of infected cells. vICA-deficient mutants, lacking either UL36 or M36, exhibit greater susceptibility to CD8 T cell control than mutants lacking the set of immunoevasins known to disrupt antigen presentation via MHC class I. This difference is evident during infection in the natural mouse host infected with MCMV, in settings where virus-specific CD8 T cells are adoptively transferred. Finally, we identify the molecular mechanism through which vICA acts, demonstrating the central contribution of caspase-8 signaling at a point of convergence of death receptor-induced apoptosis and perforin/granzyme-dependent cytotoxicity.

Abstract 13424: Dendritic Cell Surface Proteoglycan Binding-mediated Internalization of the Apob-100 Peptide P210 Increases Cd8+ T Cell Cytolytic Function

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Xiaoning Zhao ◽  
Paul C Dimayuga ◽  
Jianchang Zhou ◽  
Juliana Yano ◽  
Wai Man Lio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Cell Surface ◽  
Antigen Presentation ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Cytolytic Activity ◽  
Mhc I

Background: We have reported that immunization with the apoB-100 derived peptide p210 reduces atherosclerosis and aortic aneurysm formation/rupture, through modulation of CD8+ T cells. It remains unclear how an exogenous peptide like p210 enters dendritic cells for antigen presentation by MHC-I to CD8+ T cells. The p210 peptide sequence is located within the proteoglycan (PTG) binding site of apoB-100, which is a known alternative mechanism for cell internalization of LDL. Antigens internalized by cell surface PTG binding are cross-presented on the MHC-I molecule. We therefore tested the mechanism of p210 internalization by dendritic cell (DC) surface PTG binding and investigated the CD8+ T cell function in response to p210 antigen presentation. Methods and Results: Bone marrow derived DCs from apoE-/- mice were primed with fluorescently tagged p210 (FITC-p210) for 4 hours in vitro. There was significantly increased FITC internalization in DCs treated with FITC-p210 compared to FITC alone (24.3±2.7% vs. 6.6±0.8%; P<0.001; N=8 each) assessed by flow cytometry. Heparin significantly reduced internalization of FITC-p210 compared to no treatment (14.0±4.0%, N=4 vs. 29.9±6.7% N=9; P<0.01). Treatment of DCs with p-nitrophenyl-β-D-xylopyranoside, an inhibitor of cell surface heparan sulfate chain addition, significantly reduced FITC-p210 internalization (10.5±1.5% vs. 22.8±10.0% P<0.05, N=5 each) confirming the role of PTG binding. Adoptive transfer of p210-primed DCs into recipient apoE-/- mice significantly reduced CD8+CD25+FoxP3+ regulatory cells compared to unprimed DC controls (0.26±0.04% vs. 0.37±0.05%; N=5 each; P<0.01). Cytolytic activity against target DCs was significantly higher in CD8+ T cells from p210-primed DC recipient mice compared to controls (1.6±0.3% vs. 1.0±0.4% specific lysis; N=5 each; P<0.05). There were no significant differences in CD8+ T cell activation markers. Conclusion: Internalization of p210 is mediated in part by DC surface PTG binding, resulting in significantly reduced CD8+CD25+FoxP3+ regulatory T cells and increased cytolytic activity, suggesting unopposed CD8+ T cell effector function. Our results support the mechanism of p210 internalization by DC surface PTG increasing CD8+ T cell function.

scholarly journals Immunodominant Cytomegalovirus Epitopes Suppress Subdominant Epitopes in the Generation of High-Avidity CD8 T Cells

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 956
Author(s):  
Kirsten Freitag ◽  
Sara Hamdan ◽  
Matthias J. Reddehase ◽  
Rafaela Holtappels
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Escape ◽  
Cd8 T Cell ◽  
Antigenic Drift ◽  
Murine Cytomegalovirus ◽  
High Avidity ◽  
Infected Cells ◽  
Cd8 T Cell Memory

CD8+ T-cell responses to pathogens are directed against infected cells that present pathogen-encoded peptides on MHC class-I molecules. Although natural responses are polyclonal, the spectrum of peptides that qualify for epitopes is remarkably small even for pathogens with high coding capacity. Among those few that are successful at all, a hierarchy exists in the magnitude of the response that they elicit in terms of numbers of CD8+ T cells generated. This led to a classification into immunodominant and non-immunodominant or subordinate epitopes, IDEs and non-IDEs, respectively. IDEs are favored in the design of vaccines and are chosen for CD8+ T-cell immunotherapy. Using murine cytomegalovirus as a model, we provide evidence to conclude that epitope hierarchy reflects competition on the level of antigen recognition. Notably, high-avidity cells specific for non-IDEs were found to expand only when IDEs were deleted. This may be a host’s back-up strategy to avoid viral immune escape through antigenic drift caused by IDE mutations. Importantly, our results are relevant for the design of vaccines based on cytomegaloviruses as vectors to generate high-avidity CD8+ T-cell memory specific for unrelated pathogens or tumors. We propose the deletion of vector-encoded IDEs to avoid the suppression of epitopes of the vaccine target.

scholarly journals Serum-derived exosomes promote CD8+ T cells to overexpress PD-1, affecting the prognosis of hypopharyngeal carcinoma

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qian Gao ◽  
Hui-Ting Liu ◽  
Yu-Qin Xu ◽  
Lin Zhang ◽  
Yuan-Ru Liu ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
Programmed Cell Death ◽  
Cd8 T Cells ◽  
Poor Prognosis ◽  
Cell Function ◽  
Immune Escape ◽  
Cd8 T Cell ◽  
Serum Exosomes

Abstract Background Hypopharyngeal cancer (HPC) is associated with a poor prognosis and a high recurrence rate. Immune escape is one of the reasons for the poor prognosis of malignant tumors. Programmed cell death ligand 1 (PD-L1) and programmed cell death-1 (PD-1) have been shown to play important roles in immune escape. However, the role of PD-1/PD-L1 in HPC remains unclear. In this experiment, we investigated the effect of exosomes from HPC patient serum on CD8+ T cell function and PD-1/PD-L1 expression and, thus, on prognosis. We hope to provide guidance for the identification of new targets for HPC immunotherapy. Methods PD-1 and CD8 expression in 71 HPC tissues and 16 paracarcinoma tissues was detected by immunohistochemistry. Concurrently, the clinicopathological data of the patients were obtained to conduct correlation analysis. Exosomes were isolated from serum and then identified by Western blotting (WB), transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). Flow cytometry was used to assess the activity of CD8+ T cells after exosome stimulation. The effects of exosomes on the ability of CD8+ T cells to kill FaDu cells were assessed by CCK-8 assay. The expression of IL-10 and TGF-β1 was measured by enzyme-linked immunosorbent assay (ELISA). PD-L1 expression in HPC tissue samples was evaluated by immunohistochemistry, and the relationship between PD-1/PD-L1 expression and prognosis was investigated with patient specimens. Results PD-1 expression was significantly upregulated on CD8+ T cells in tumor tissues compared with those in normal tissues. The overall survival (OS) and disease-free survival (DFS) of PD-1-overexpressing patients were decreased. Serum exosomes from patients can elevate PD-1 expression on CD8+ T cells and suppress their killing capacity and secretory function. The rate of positive PD-L1 expression was increased in HPC tissues compared with paracancerous tissues. The DFS and OS of the PD-1(+)-PD-L1(+) group were significantly lower than those of the PD-1(−)-PD-L1(−) group. Conclusion Our findings indicate that serum exosomes from HPC patients can inhibit CD8+ T cell function and that the PD-1-PD-L1 pathway plays an important role in the immune escape of HPC. Exosomes combined with immunotherapy may guide the treatment of patients with advanced disease in the future.

scholarly journals Divergent Impact of Glucose Availability on Human Virus-Specific and Generically Activated CD8 T Cells

Metabolites ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 461
Author(s):  
Jenifer Sanchez ◽  
Ian Jackson ◽  
Katie R. Flaherty ◽  
Tamara Muliaditan ◽  
Anna Schurich
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Cell Immune Response ◽  
Complex Nature ◽  
Human Virus ◽  
Glucose Availability

Upon activation T cells engage glucose metabolism to fuel the costly effector functions needed for a robust immune response. Consequently, the availability of glucose can impact on T cell function. The glucose concentrations used in conventional culture media and common metabolic assays are often artificially high, representing hyperglycaemic levels rarely present in vivo. We show here that reducing glucose concentration to physiological levels in culture differentially impacted on virus-specific compared to generically activated human CD8 T cell responses. In virus-specific T cells, limiting glucose availability significantly reduced the frequency of effector-cytokine producing T cells, but promoted the upregulation of CD69 and CD103 associated with an increased capacity for tissue retention. In contrast the functionality of generically activated T cells was largely unaffected and these showed reduced differentiation towards a residency phenotype. Furthermore, T cells being cultured at physiological glucose concentrations were more susceptible to viral infection. This setting resulted in significantly improved lentiviral transduction rates of primary cells. Our data suggest that CD8 T cells are exquisitely adapted to their niche and provide a reminder of the need to better mimic physiological conditions to study the complex nature of the human CD8 T cell immune response.

scholarly journals The Level of Viral Antigen Presented by Hepatocytes Influences CD8 T-Cell Function

2007 ◽  
Vol 81 (6) ◽  
pp. 2940-2949 ◽  
Author(s):  
Adam J. Gehring ◽  
Dianxing Sun ◽  
Patrick T. F. Kennedy ◽  
Esther Nolte-'t Hoen ◽  
Seng Gee Lim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Viral Antigen ◽  
Cell Function ◽  
Cd8 T Cell ◽  
T Cell Function ◽  
Tnf Α ◽  
Antiviral Function ◽  
Ifn Γ

ABSTRACT CD8 T cells exert their antiviral function through cytokines and lysis of infected cells. Because hepatocytes are susceptible to noncytolytic mechanisms of viral clearance, CD8 T-cell antiviral efficiency against hepatotropic viruses has been linked to their capacity to produce gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α). On the other hand, intrahepatic cytokine production triggers the recruitment of mononuclear cells, which sustain acute and chronic liver damage. Using virus-specific CD8 T cells and human hepatocytes, we analyzed the modulation of virus-specific CD8 T-cell function after recognition peptide-pulsed or virally infected hepatocytes. We observed that hepatocyte antigen presentation was generally inefficient, and the quantity of viral antigen strongly influenced CD8 T-cell antiviral function. High levels of hepatitis B virus production induced robust IFN-γ and TNF-α production in virus-specific CD8 T cells, while limiting amounts of viral antigen, both in hepatocyte-like cells and naturally infected human hepatocytes, preferentially stimulated CD8 T-cell degranulation. Our data document a mechanism where virus-specific CD8 T-cell function is influenced by the quantity of virus produced within hepatocytes.

Histone Deacetylase 11 (HDAC11) Regulates Cytotoxic T-Cell Function and Memory Phenotype

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 840-840
Author(s):  
David M Woods ◽  
Karrune V. Woan ◽  
Eva Sahakian ◽  
John Powers ◽  
Fengdong Cheng ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Central Memory ◽  
Negative Regulator ◽  
Wild Type ◽  
Potential Target ◽  
T Cell Function

Abstract Abstract 840 T-cells are an essential component of immune mediated tumor rejection. Adoptive transfer of T-cells results in a durable anti-tumor response in some patients with hematological malignancies. To further improve the efficacy of T-cell adoptive transfers, a better understanding of the regulatory checkpoints of these cells is needed. Here we show that HDAC11 is a negative regulator of CD8+ T-cell function, thus representing a potential target in adoptive immunotherapy. HDACs are a group of enzymes initially known for their role in deacetylating histones, thereby condensing chromatin structure and repressing gene expression. The known roles of HDACs as epigenetic regulators have recently expanded to include more complex regulatory functions including interactions with non-histone targets. HDAC11 is the most recently identified member of the HDAC family, and is highly expressed in brain, testis and T-cells. Recently, our group reported HDAC11 as a regulator of IL-10 production in antigen presenting cells. To determine the role of HDAC11 in T-cell biology, T-cells from HDAC11 knock out (HDAC11KO) mice were compared to wild-type T-cells in number, function and phenotype. HDAC11KO T-cells had no differences in absolute number or percentages of CD4+ or CD8+ lymphocytes. However CD8+ T-cells were hyper-proliferative upon CD3/CD28 stimulation and produced significantly higher levels of the pro-inflammatory, Tc1 cytokines IL-2, INF-γ, and TNF-α. However, no significant increases in the production of the Tc2 cytokines IL-4, IL-6 or IL-10 were seen. Further investigation of phenotypic differences also revealed that HDAC11KO mice have a larger percentage of central memory CD8+ T-cells. Additionally, HDAC11KO CD8+ T-cells express higher levels of the transcription factor Eomes, a known contributor to central memory cell formation as well as a controller of granzyme B and perforin production in CD8+ T-cells. This Tc1 and central memory-like phenotype translated to delayed tumor progression and survival in vivo in C1498 AML bearing mice treated with adoptively transferred HDAC11KO T-cells, as compared with wild type T-cells. Collectively, we have demonstrated HDAC11 as a negative regulator of CD8+ T-cell function, and a novel potential target to augment the efficacy of adoptive T-cell tumor immunotherapy. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Immune Evasion Paradox: Immunoevasins of Murine Cytomegalovirus Enhance Priming of CD8 T Cells by Preventing Negative Feedback Regulation

2008 ◽  
Vol 82 (23) ◽  
pp. 11637-11650 ◽  
Author(s):  
Verena Böhm ◽  
Christian O. Simon ◽  
Jürgen Podlech ◽  
Christof K. Seckert ◽  
Dorothea Gendig ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Negative Feedback ◽  
Cd8 T Cells ◽  
Viral Gene Expression ◽  
Cd8 T Cell ◽  
Murine Cytomegalovirus ◽  
Viral Gene ◽  
Infected Cells

ABSTRACT Cytomegaloviruses express glycoproteins that interfere with antigen presentation to CD8 T cells. Although the molecular modes of action of these “immunoevasins” differ between cytomegalovirus species, the convergent biological outcome is an inhibition of the recognition of infected cells. In murine cytomegalovirus, m152/gp40 retains peptide-loaded major histocompatibility complex class I molecules in a cis-Golgi compartment, m06/gp48 mediates their vesicular sorting for lysosomal degradation, and m04/gp34, although not an immunoevasin in its own right, appears to assist in the concerted action of all three molecules. Using the Ld-restricted IE1 epitope YPHFMPTNL in the BALB/c mouse model as a paradigm, we provide here an explanation for the paradox that immunoevasins enhance CD8 T-cell priming although they inhibit peptide presentation in infected cells. Adaptive immune responses are initiated in the regional lymph node (RLN) draining the site of pathogen exposure. In particular for antigens that are not virion components, the magnitude of viral gene expression providing the antigens is likely a critical parameter in priming efficacy. We have therefore focused on the events in the RLN and have related priming to intranodal viral gene expression. We show that immunoevasins enhance priming by downmodulating an early CD8 T-cell-mediated “negative feedback” control of the infection in the cortical region of the RLN, thus supporting the model that immunoevasins improve antigen supply for indirect priming by uninfected antigen-presenting cells. As an important consequence, these findings predict that deletion of immunoevasin genes in a replicative vaccine virus is not a favorable option but may, rather, be counterproductive.

scholarly journals Empty conformers of HLA-B preferentially bind CD8 and regulate CD8+ T cell function

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Jie Geng ◽  
John D Altman ◽  
Sujatha Krishnakumar ◽  
Malini Raghavan
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Surface ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Cell Surface Expression ◽  
Antigenic Peptides

When complexed with antigenic peptides, human leukocyte antigen (HLA) class I (HLA-I) molecules initiate CD8+ T cell responses via interaction with the T cell receptor (TCR) and co-receptor CD8. Peptides are generally critical for the stable cell surface expression of HLA-I molecules. However, for HLA-I alleles such as HLA-B*35:01, peptide-deficient (empty) heterodimers are thermostable and detectable on the cell surface. Additionally, peptide-deficient HLA-B*35:01 tetramers preferentially bind CD8 and to a majority of blood-derived CD8+ T cells via a CD8-dependent binding mode. Further functional studies reveal that peptide-deficient conformers of HLA-B*35:01 do not directly activate CD8+ T cells, but accumulate at the immunological synapse in antigen-induced responses, and enhance cognate peptide-induced cell adhesion and CD8+ T cell activation. Together, these findings indicate that HLA-I peptide occupancy influences CD8 binding affinity, and reveal a new set of regulators of CD8+ T cell activation, mediated by the binding of empty HLA-I to CD8.

scholarly journals LINC01355 Contributes to Malignant Phenotype of Oral Squamous Cell Carcinoma and Cytotoxic T Cell Infiltration via Activating Notch Signaling Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Chen Zou ◽  
Siyuan Wu ◽  
Haigang Wei ◽  
Hailing Luo ◽  
Zhe Tang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antitumor Activity ◽  
Notch Signaling ◽  
Cd8 T Cells ◽  
Cell Activity ◽  
Cd8 T Cell ◽  
Cytotoxic T Cell ◽  
Migration And Invasion ◽  
Notch Signal

LINC01355 has been demonstrated to be dysregulated in several cancers. However, the exact molecular function of LINC01355 in the pathogenesis of OSCC remains unstudied. Here, we reported the effect of LINC01355 in OSCC and investigated the mechanisms. Firstly, we found that the results indicated LINC01355 was increased in OSCC cells. Knockdown of LINC01355 repressed OSCC cell proliferation, migration, and invasion. Recently, immunotherapy is a significant method for the treatment of cancers, in which CD8+ T cells exhibit a significant role. The influence of LINC01355 on the antitumor activity of CD8+ T cells was also focused in this study. As shown, the silence of LINC01355 could repress OSCC tumor growth via inducing CD8+ T cell immune responses. In addition, we found that downregulation of LINC01355 significantly restrained CD8+ T cell apoptosis, induced CD8+ T cell percentage, and enhanced the cytolysis activity when cocultured with OSCC cells. It has been reported that the Notch pathway represses CD8+ T cell activity in cancer patients. In our present study, we displayed that lack of LINC01355 suppressed OSCC malignant behaviors and enhanced the antitumor activity of CD8+ T cells via inactivating Notch signaling. We showed that decreased LINC01355 significantly restrained the Notch signal via a decrease of Notch-1, JAG-1, and HES-1. Repression of Notch1 reversed the effect of LINC01355 in OSCC cells. In conclusion, it was implied that LINC01355 might induce the development of OSCC via modulating the Notch signal pathway, which could provide a candidate therapeutic target for OSCC.

scholarly journals Combination rhIL-15 and Anti-PD-L1 (Avelumab) Enhances HIVGag-Specific CD8 T-Cell Function

2020 ◽  
Vol 222 (9) ◽  
pp. 1540-1549
Author(s):  
Bruktawit A Goshu ◽  
Hui Chen ◽  
Maha Moussa ◽  
Jie Cheng ◽  
Marta Catalfamo
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Cd8 T Cell ◽  
Peripheral Tissues ◽  
T Cell Function ◽  
Interleukin 15 ◽  
Checkpoint Receptors

Abstract In chronic HIV infection, virus-specific cytotoxic CD8 T cells showed expression of checkpoint receptors and impaired function. Therefore, restoration of CD8 T-cell function is critical in cure strategies. Here, we show that in vitro blockade of programmed cell death ligand 1 (PD-L1) by an anti-PD-L1 antibody (avelumab) in combination with recombinant human interleukin-15 (rhIL-15) synergistically enhanced cytokine secretion by proliferating HIVGag-specific CD8 T cells. In addition, these CD8 T cells have a CXCR3+PD1−/low phenotype, suggesting a potential to traffic into peripheral tissues. In vitro, proliferating CD8 T cells express PD-L1 suggesting that anti-PD-L1 treatment also targets virus-specific CD8 T cells. Together, these data indicate that rhIL-15/avelumab combination therapy could be a useful strategy to enhance CD8 T-cell function in cure strategies.

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