Molecular Basis of T-Cell Exhaustion

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. SCI-38-SCI-38
Author(s):  
E. John Wherry

Abstract T-cell exhaustion is common during chronic infections, cancer, exposure to persisting antigens, and can prevent optimal immunity. Exhausted T cells are defined by the loss of ability to perform effector functions efficiently, low proliferative capacity, and poor survival following antigen stimulation. In addition, it has become clear that exhausted T cells co-express multiple inhibitory receptors that negatively regulate their function. Indeed, receptors such as PD-1 have become major targets of clinical immunotherapies in cancer and infectious disease aimed at re-invigorating exhausted T cells. Our work has recently defined transcriptional networks of T-cell exhaustion and has focused on the role of key transcription factors, including T-bet and Eomesodermin (Eomes), in controlling the sustainability and terminal differentiation of exhausted T cell populations. Chronic infections and persisting antigen exposure often strains the sustainability or regenerative capacity of exhausted T cell populations resulting in an eventual collapse in immunity. We have found a key role for T-bet in sustaining a progenitor pool of exhausted CD8 T cells during chronic infection, while the related transcription factor Eomes governs terminal differentiation. These represent unique functions for T-bet and Eomes since these transcription factors are associated with different roles in functional memory T cells, highlighting the contextual dependence of transcriptional regulation guiding T-cell exhaustion. Additional studies are focusing on the role of other transcription factors such as BATF in T-cell activation and exhaustion, and on the role of inhibitory receptors including PD-1 in shaping the differentiation of exhausted CD8 T-cell subsets. Ultimately, a more precise molecular understanding of T-cell exhaustion should lead to novel and more robust clinical interventions to reverse exhaustion in settings of persisting infections and cancer. Disclosures: Wherry: Genentech: Patents & Royalties.

2021 ◽  
Author(s):  
Susetta Finotto ◽  
Patricia Haag ◽  
Darja Andreev ◽  
Nina Li ◽  
Alexander Kiefer ◽  
...  

Abstract Background: Serum 25(OH)-Vitamin D3 (VitD3) deficiency during infancy has been associated with asthma. The potential therapeutic role of VitD3 given in the airways and its interference with the allergen and Rhinovirus was the objective of this study. Methods: In two cohorts of children with and without asthma, serum levels of the C-reactive protein (CRP) were correlated to Serum VitD3 and in peripheral blood T cell inhibitor marker Programmed cell death protein 1 (PD1) mRNA was analyzed. In a murine model, VitD3 was given intranasally in vivo and in vitro to lung cells with allergen and Rhinovirus. Results: In the cohorts of pre-school age children without (control) asthma, CRP and VitD3 levels inversely correlated. In preschool asthmatic children that did not receive VitD3 supplementation as infant had more episode of asthma exacerbation associated with high CRP serum level. In peripheral blood cells from control but not asthmatic children with higher serum levels of VitD3 had lower PD1 mRNA levels. In murine model, OVA intranasal challenge induced Innate Lymphoid Cells type 2 (ILC2)-associated markers and Eosinophils in BALF and VitD3 inhibited lung inflammation and ILC2 markers. Furthermore, VitD3 given intranasally, induced CD4+T cells and reduced PD1, T regulatory cells in the lung. Similarly, VitD3 had a suppressive role on CD4+PD1+ T cells involved in T cell exhaustion in the airways in the absence of ST2 after Rhinovirus infection. Conclusion: These data support an inhibitory role of VitD3 on T cell exhaustion after allergen and rhinovirus infection that is relevant for pediatric asthma.


Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 156 ◽  
Author(s):  
Shannon Kahan ◽  
Allan Zajac

Lymphocytic choriomeningitis virus (LCMV) is a paradigm-forming experimental system with a remarkable track record of contributing to the discovery of many of the fundamental concepts of modern immunology. The ability of LCMV to establish a chronic infection in immunocompetent adult mice was instrumental for identifying T cell exhaustion and this system has been invaluable for uncovering the complexity, regulators, and consequences of this state. These findings have been directly relevant for understanding why ineffective T cell responses commonly arise during many chronic infections including HIV and HCV, as well as during tumor outgrowth. The principal feature of exhausted T cells is the inability to elaborate the array of effector functions necessary to contain the underlying infection or tumor. Using LCMV to determine how to prevent and reverse T cell exhaustion has highlighted the potential of checkpoint blockade therapies, most notably PD-1 inhibition strategies, for improving cellular immunity under conditions of antigen persistence. Here, we discuss the discovery, properties, and regulators of exhausted T cells and highlight how LCMV has been at the forefront of advancing our understanding of these ineffective responses.


2018 ◽  
Vol 86 (9) ◽  
Author(s):  
Eileen A. Wong ◽  
Louis Joslyn ◽  
Nicole L. Grant ◽  
Edwin Klein ◽  
Philana Ling Lin ◽  
...  

ABSTRACTThe hallmarks of pulmonaryMycobacterium tuberculosisinfection are lung granulomas. These organized structures are composed of host immune cells whose purpose is to contain or clear infection, creating a complex hub of immune and bacterial cell activity, as well as limiting pathology in the lungs. Yet, given cellular activity and the potential for frequent interactions between host immune cells andM. tuberculosis-infected cells, we observed a surprisingly low quantity of cytokine-producing T cells (<10% of granuloma T cells) in our recent study ofM. tuberculosisinfection within nonhuman primate (NHP) granulomas. Various mechanisms could limit T cell function, and one hypothesis is T cell exhaustion. T cell exhaustion is proposed to result from continual antigen stimulation, inducing them to enter a state characterized by low cytokine production, low proliferation, and expression of a series of inhibitory receptors, the most common being PD-1, LAG-3, and CTLA-4. In this work, we characterized the expression of inhibitory receptors on T cells and the functionality of these cells in tuberculosis (TB) lung granulomas. We then used these experimental data to calibrate and inform an agent-based computational model that captures environmental, cellular, and bacterial dynamics within granulomas in lungs duringM. tuberculosisinfection. Together, the results of the modeling and the experimental work suggest that T cell exhaustion alone is not responsible for the low quantity ofM. tuberculosis-responsive T cells observed within TB granulomas and that the lack of exhaustion is likely an intrinsic property of granuloma structure.


2021 ◽  
Author(s):  
Yini Sun ◽  
Renyu Ding ◽  
Yukun Chang ◽  
Jiuming Li ◽  
Xiaochun Ma

Abstract Background: Sepsis-induced T cell exhaustion that is characterized by upregulated coinhibitory molecules and decreased cytokines release plays a crucial role in the immunosuppression during sepsis. Although PD-1 has shown a promising target to interfere with T cells dysfunction, the role of other coinhibitory receptors in sepsis remains largely elusive. Recently, it has been demonstrated that the coinhibitory molecule TIGIT more reliably identified exhausted T cells than PD-1. The aim of the study was to identify the expression of TIGIT on lymphocytes and the crucial role of TIGIT in modulating T cell function in septic patients. Methods: Twenty-five patients with sepsis and seventeen healthy controls were prospectively enrolled. Peripheral blood was obtained from septic patients within 24 hours after diagnosis of sepsis, as were healthy controls. TIGIT and other coinhibitory/costimulatory molecules expression on lymphocyte subsets was quantitated by flow cytometry. The relationship between TIGIT expression and clinical parameters was simultaneously evaluated. The function T cell from septic patients was assayed via stimulated cytokine secretion. Ex vivo functional assays were also conducted.Results: In the early stage of sepsis, patients exhibited higher levels of TIGIT on T cells relative to healthy donors, especially in the septic shock patients. Elevated frequencies of TIGIT + T cells positively correlated with the severity of organ failure and inflammatory responses in septic patients. TIGIT + T cells expressed higher levels of PD-1 and lower CD226. Further, elevated expression of TIGIT inhibited the release of cytokines including TNF, IFN-γ and IL-2 by CD4 + and CD8 + T cells. Strikingly, ex vivo blockade of TIGIT using anti-TIGIT antibody restored the frequencies of cytokine-producing T cells. Conclusions: These data illustrate TIGIT as a novel marker of exhausted T cells and suggest TIGIT may be a novel immunotherapeutic target during sepsis.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A554-A554
Author(s):  
Rhodes Ford ◽  
Paolo Vignali ◽  
Natalie Rittenhouse ◽  
Nicole Scharping ◽  
Andrew Frisch ◽  
...  

BackgroundTumor-infiltrating CD8+ T cells have been characterized by their exhausted phenotype with decreased cytokine expression and increased expression of co-inhibitory receptors, such as PD-1 and Tim-3. These receptors mark the progression towards exhaustion from a progenitor stage (PD-1Low) to a terminally exhausted stage (PD-1+Tim-3+). While the epigenetics of tumor-infiltrating T cells are unique compared to naïve, effector, and memory populations, how the chromatin landscape changes during this progression has not been described.MethodsUsing a low-input ChIP-based assay called Cleavage Under Targets and Release Using Nuclease (CUT&RUN), we profiled the histone modifications at the chromatin of tumor-infiltrating CD8+ T cell subsets to better understand the relationship between the epigenome and the transcriptome as TIL progress towards terminal exhaustion.ResultsWe have identified two epigenetic characteristics unique to terminally exhausted cells. First, we found a substantial increase in the number of genes that exhibit bivalent chromatin marks, defined by the presence of both activating (H3K4me3) and repressive (H3K27me3) epigenetic modifications that inhibit gene expression. In contrast to stem cells which exhibit bivalency, bivalent genes in terminally exhausted T cells are not associated with plasticity and represent aberrant hypermethylation in response to tumor hypoxia. Secondly, we have also identified a unique set of enhancers, characterized by H3K27ac that do not drive gene expression. These enhancers are enriched for AP-1 transcription factors, whereas enhancers that correlate with gene transcription are enriched for nuclear receptor (NR) transcription factors. Intriguingly, while most AP-1 and NR transcription factors are not expressed in terminally exhausted cells, we found that Batf, an inhibitory AP-1 family member, and Nr4a2, a NR known to promote both exhaustion and modify chromatin were specifically expressed in terminally exhausted cells. These data suggest the balance of Batf and Nr4a2 may modulate the enhancer landscape to promote terminal exhaustion, while hypoxia simultaneously promotes hypermethylation and gene repression.ConclusionsOur study defines for the first time the features of epigenetic dysfunction in tumor-mediated T cell exhaustion and deepens our understanding of the epigenetic regulation of gene expression. These observations are the bases for future work that will elucidate that factors that drive progression towards terminal T cell exhaustion at the epigenetic level and identify novel therapeutic targets to restore effector function of tumor T cells and mediate tumor clearance.


2021 ◽  
Vol 9 (4) ◽  
pp. e002189
Author(s):  
Najmeh Bozorgmehr ◽  
Isobel Okoye ◽  
Olaide Oyegbami ◽  
Lai Xu ◽  
Amelie Fontaine ◽  
...  

BackgroundT cell exhaustion compromises antitumor immunity, and a sustained elevation of co-inhibitory receptors is a hallmark of T cell exhaustion in solid tumors. Similarly, upregulation of co-inhibitory receptors has been reported in T cells in hematological cancers such as chronic lymphocytic leukemia (CLL). However, the role of CD160, a glycosylphosphatidylinositol-anchored protein, as one of these co-inhibitory receptors has been contradictory in T cell function. Therefore, we decided to elucidate how CD160 expression and/or co-expression with other co-inhibitory receptors influence T cell effector functions in patients with CLL.MethodsWe studied 56 patients with CLL and 25 age-matched and sex-matched healthy controls in this study. The expression of different co-inhibitory receptors was analyzed in T cells obtained from the peripheral blood or the bone marrow. Also, we quantified the properties of extracellular vesicles (EVs) in the plasma of patients with CLL versus healthy controls. Finally, we measured 29 different cytokines, chemokines or other biomarkers in the plasma specimens of patients with CLL and healthy controls.ResultsWe found that CD160 was the most upregulated co-inhibitory receptor in patients with CLL. Its expression was associated with an exhausted T cell phenotype. CD160+CD8+ T cells were highly antigen-experienced/effector T cells, while CD160+CD4+ T cells were more heterogeneous. In particular, we identified EVs as a source of CD160 in the plasma of patients with CLL that can be taken up by T cells. Moreover, we observed a dominantly proinflammatory cytokine profile in the plasma of patients with CLL. In particular, interleukin-16 (IL-16) was highly elevated and correlated with the advanced clinical stage (Rai). Furthermore, we observed that the incubation of T cells with IL-16 results in the upregulation of CD160.ConclusionsOur study provides a novel insight into the influence of CD160 expression/co-expression with other co-inhibitory receptors in T cell effector functions in patients with CLL. Besides, IL-16-mediated upregulation of CD160 expression in T cells highlights the importance of IL-16/CD160 as potential immunotherapy targets in patients with CLL. Therefore, our findings propose a significant role for CD160 in T cell exhaustion in patients with CLL.


Blood ◽  
2013 ◽  
Vol 121 (4) ◽  
pp. 604-613 ◽  
Author(s):  
Tamara Kögl ◽  
Jürgen Müller ◽  
Birthe Jessen ◽  
Annette Schmitt-Graeff ◽  
Gritta Janka ◽  
...  

Abstract Syntaxin-11 (Stx11), an atypical member of the SNARE protein family, is part of the cytolytic machinery of T and NK cells and involved in the fusion of lytic granules with the plasmamembrane. Functional loss of syntaxin-11 in humans causes defective degranulation and impaired cytolytic activity of T and NK cells. Furthermore, patients with STX11 deficiency develop familial hemophagocytic lymphohistiocytosis type 4 (FHL4), a life-threatening disease of severe hyperinflammation. We established Stx11-deficient mice as an animal model for FHL4. Stx11-deficient mice exhibited severely reduced degranulation and cytolytic activity of CTL and NK cells and developed all clinical symptoms of hemophagocytic lymphohistiocytosis (HLH) after infection with lymphocytic choriomeningitis virus (LCMV). The HLH phenotype was further characterized by hyperactive CD8 T cells and continuous IFN-γ production. However, in contrast to perforin-deficient mice, which represent a model for FHL2, progression of HLH was not fatal. Survival of Stx11-deficient mice was determined by exhaustion of antigen-specific T cells, characterized by expression of inhibitory receptors, sequential loss of effector functions, and finally T-cell deletion. Blockade of inhibitory receptors on T cells in Stx11-deficient mice converted nonfatal disease course into fatal HLH, identifying T-cell exhaustion as an important factor for determination of disease severity in HLH.


2016 ◽  
Vol 213 (9) ◽  
pp. 1799-1818 ◽  
Author(s):  
SuJin Hwang ◽  
Dustin A. Cobb ◽  
Rajarshi Bhadra ◽  
Ben Youngblood ◽  
Imtiaz A. Khan

CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported in Toxoplasma encephalitis (TE)–susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent conditional Blimp-1 knockout mixed bone marrow chimera as well as an adoptive transfer approach, we show that CD4 T cell–intrinsic deletion of Blimp-1 reversed CD8 T cell dysfunction and resulted in improved pathogen control. To the best of our knowledge, this is a novel finding, which demonstrates the role of Blimp-1 as a critical regulator of CD4 dysfunction and links it to the CD8 T cell dysfunctionality observed in infected mice. The critical role of CD4-intrinsic Blimp-1 expression in mediating CD4 and CD8 T cell exhaustion may provide a rational basis for designing novel therapeutic approaches.


2020 ◽  
Vol 6 (24) ◽  
pp. eaba3458 ◽  
Author(s):  
Jingxia Wu ◽  
Nina Weisshaar ◽  
Agnes Hotz-Wagenblatt ◽  
Alaa Madi ◽  
Sicong Ma ◽  
...  

CD8+ T cells become functionally impaired or “exhausted” in chronic infections, accompanied by unwanted body weight reduction and muscle mass loss. Whether muscle regulates T cell exhaustion remains incompletely understood. We report that mouse skeletal muscle increased interleukin (IL)–15 production during LCMV clone 13 chronic infection. Muscle-specific ablation of Il15 enhanced the CD8+ T cell exhaustion phenotype. Muscle-derived IL-15 was required to maintain a population of CD8+CD103+ muscle-infiltrating lymphocytes (MILs). MILs resided in a less inflamed microenvironment, expressed more T cell factor 1 (Tcf1), and had higher proliferative potential than splenic T cells. MILs differentiated into functional effector T cells after reentering lymphoid tissues. Increasing muscle mass via muscle-specific inhibition of TGFβ signaling enhanced IL-15 production and antiviral CD8+ T cell responses. We conclude that skeletal muscle antagonizes T cell exhaustion by protecting T cell proliferative potential from inflammation and replenishing the effector T cell progeny pool in lymphoid organs.


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