Increased expression of the natural killer cell inhibitory receptor CD85j/ILT2 on antigen-specific effector CD8 T cells and its impact on CD8 T-cell function

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.

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

Metabolites ◽

10.3390/metabo10110461 ◽

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.

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1914667117 ◽

2020 ◽

Vol 117 (23) ◽

pp. 12961-12968 ◽

Cited By ~ 3

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.

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

Journal of Virology ◽

10.1128/jvi.02415-06 ◽

2007 ◽

Vol 81 (6) ◽

pp. 2940-2949 ◽

Cited By ~ 58

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.

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

Blood ◽

10.1182/blood.v120.21.840.840 ◽

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.

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

eLife ◽

10.7554/elife.36341 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 14

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.

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Low immunogenicity of malaria pre-erythrocytic stages can be overcome by vaccination

10.1101/2020.09.03.281238 ◽

2020 ◽

Author(s):

Katja Müller ◽

Matthew P. Gibbins ◽

Arturo Reyes-Sandoval ◽

Adrian V. S. Hill ◽

Simon J. Draper ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Parasitophorous Vacuole ◽

Cd8 T Cell ◽

Major Protein ◽

Surface Coat ◽

Protective Antigens ◽

Malaria Vaccines ◽

Specific Effector

ABSTRACTVaccine discovery and development critically depends on predictive assays, which prioritise protective antigens. Immunogenicity is considered one important criterion for progression of candidate vaccines to further clinical evaluation, including phase I/II trials. Here, we tested this assumption in an infection and vaccination model for malaria pre-erythrocytic stages. We engineered Plasmodium berghei parasites that harbour a well-characterised epitope for stimulation of CD8+ T cells either as an antigen in the circumsporozoite protein (CSP), the surface coat protein of extracellular sporozoites or in the upregulated in sporozoites 4 (UIS4), a major protein associated with the parasitophorous vacuole membrane (PVM) that surrounds the intracellular exo-erythrocytic forms (EEF). We show that the antigen origin results in profound differences in immunogenicity with a sporozoite antigen eliciting robust and superior antigen-specific CD8+ T cell responses, whilst an EEF antigen evokes poor responses. However, despite their contrasting immunogenic properties, both sporozoite and EEF antigens gain access to antigen presentation pathways in hepatocytes, as recognition and targeting by vaccine-induced, antigen-specific effector CD8+ T cells results in high levels of protection when targeting both antigens. Our study is the first demonstration that poor immunogenicity of EEF antigens does not preclude their susceptibility to antigen-specific CD8+ T cell killing. Our findings that antigen immunogenicity is an inadequate predictor of vaccine susceptibility have wide-ranging implications on antigen prioritisation for the design and testing of next-generation pre-erythrocytic malaria vaccines.

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

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa269 ◽

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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Protective Immunity against Secondary Poxvirus Infection Is Dependent on Antibody but Not on CD4 or CD8 T-Cell Function

Journal of Virology ◽

10.1128/jvi.00115-06 ◽

2006 ◽

Vol 80 (13) ◽

pp. 6333-6338 ◽

Cited By ~ 79

Author(s):

Vijay Panchanathan ◽

Geeta Chaudhri ◽

Gunasegaran Karupiah

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Primary Infection ◽

Protective Immunity ◽

Cell Function ◽

Secondary Infection ◽

Cd8 T Cell ◽

Ectromelia Virus ◽

T Cell Function

ABSTRACT Renewed interest in smallpox and the need for safer vaccines have highlighted our lack of understanding of the requirements for protective immunity. Since smallpox has been eradicated, surrogate animal models of closely related orthopoxviruses, such as ectromelia virus, have been used to establish critical roles for CD8 T cells in the control of primary infection. To study the requirements for protection against secondary infection, we have used a prime-challenge regime, in which avirulent ectromelia virus was used to prime mice that were then challenged with virulent ectromelia virus. In contrast to primary infection, T cells are not required for recovery from secondary infection, since gene knockout mice deficient in CD8 T-cell function and wild-type mice acutely depleted of CD4, CD8, or both subsets were fully protected. Protection correlated with effective virus control and generation of neutralizing antibody. Notably, primed mice that lacked B cells, major histocompatibility complex class II, or CD40 succumbed to secondary infection. Thus, antibody is essential, but CD4 or CD8 T cells are not required for recovery from secondary poxvirus infection.

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Obligatory Requirement for Antibody in Recovery from a Primary Poxvirus Infection

Journal of Virology ◽

10.1128/jvi.00116-06 ◽

2006 ◽

Vol 80 (13) ◽

pp. 6339-6344 ◽

Cited By ~ 73

Author(s):

Geeta Chaudhri ◽

Vijay Panchanathan ◽

Horst Bluethmann ◽

Gunasegaran Karupiah

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

B Cell ◽

Cd8 T Cells ◽

Cell Function ◽

Cd8 T Cell ◽

T Cell Response ◽

Ectromelia Virus ◽

B Cell Function

ABSTRACT To understand the correlates of protective immunity against primary variola virus infection in humans, we have used the well-characterized mousepox model. This is an excellent surrogate small-animal model for smallpox in which the disease is caused by infection with the closely related orthopoxvirus, ectromelia virus. Similarities between the two infections include virus replication and transmission, aspects of pathology, and development of pock lesions. Previous studies using ectromelia virus have established critical roles for cytokines and effector functions of CD8 T cells in the control of acute stages of poxvirus infection. Here, we have used mice deficient in B cells to demonstrate that B-cell function is also obligatory for complete virus clearance and recovery of the host. In the absence of B cells, virus persists and the host succumbs to infection, despite the generation of CD8 T-cell responses. Intriguingly, transfer of naive B cells or ectromelia virus-immune serum to B-cell-deficient mice with established infection allowed these animals to clear virus and fully recover. In contrast, transfer of ectromelia virus-immune CD8 T cells was ineffective. Our data show that mice deficient in CD8 T-cell function die early in infection, whereas those deficient in B cells or antibody production die much later, indicating that B-cell function becomes critical after the effector phase of the CD8 T-cell response to infection subsides. Strikingly, our results show that antibody prevents virus from seeding the skin and forming pock lesions, which are important for virus transmission between hosts.

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