CD39 expression identifies terminally exhausted CD8+ T cells
Ontology highlight
ABSTRACT: Exhausted T cells express multiple co-inhibitory molecules that impair their function and limit immunity to chronic viral infection. Defining novel markers of exhaustion is important both for identifying and potentially reversing T cell exhaustion. Herein, we show that the ectonucleotidse CD39 is a marker of exhausted CD8+ T cells. CD8+ T cells specific for HCV or HIV express high levels of CD39, but those specific for EBV and CMV do not. CD39 expressed by CD8+ T cells in chronic infection is enzymatically active, co-expressed with PD-1, marks cells with a transcriptional signature of T cell exhaustion and correlates with viral load in HIV and HCV. In the mouse model of chronic Lymphocytic Choriomeningitis Virus infection, virus-specific CD8+ T cells contain a population of CD39high CD8+ T cells that is absent in functional memory cells elicited by acute infection. This CD39high CD8+ T cell population is enriched for cells with the phenotypic and functional profile of terminal exhaustion. These findings provide a new marker of T cell exhaustion, and implicate the purinergic pathway in the regulation of T cell exhaustion. CD8+ T cells from subjects with HCV infection were sorted and pelleted and re-suspended in TRIzol (Invitrogen). RNA extraction was performed using the RNAdvance Tissue Isolation kit (Agencourt). Concentrations of total RNA were determined with a Nanodrop spectrophotometer or Ribogreen RNA quantification kits (Molecular Probes/Invitrogen). RNA purity was determined by Bioanalyzer 2100 traces (Agilent Technologies). Total RNA was amplified with the WT-Ovation Pico RNA Amplification system (NuGEN) according to the manufacturer's instructions. After fragmentation and biotinylation, cDNA was hybridized to HG-U133A 2.0 microarrays (Affymetrix).
Project description:Exhausted T cells express multiple co-inhibitory molecules that impair their function and limit immunity to chronic viral infection. Defining novel markers of exhaustion is important both for identifying and potentially reversing T cell exhaustion. Herein, we show that the ectonucleotidse CD39 is a marker of exhausted CD8+ T cells. CD8+ T cells specific for HCV or HIV express high levels of CD39, but those specific for EBV and CMV do not. CD39 expressed by CD8+ T cells in chronic infection is enzymatically active, co-expressed with PD-1, marks cells with a transcriptional signature of T cell exhaustion and correlates with viral load in HIV and HCV. In the mouse model of chronic Lymphocytic Choriomeningitis Virus infection, virus-specific CD8+ T cells contain a population of CD39high CD8+ T cells that is absent in functional memory cells elicited by acute infection. This CD39high CD8+ T cell population is enriched for cells with the phenotypic and functional profile of terminal exhaustion. These findings provide a new marker of T cell exhaustion, and implicate the purinergic pathway in the regulation of T cell exhaustion.
Project description:CD8+ T cells in chronic viral infections like HIV develop functional defects such as loss of IL-2 secretion and decreased proliferative potential that are collectively termed exhaustion1. Exhausted T cells express increased levels of multiple inhibitory receptors, such as Programmed Death 1 (PD-1). PD-1 inhibition contributes to impaired virus-specific T cell function in chronic infection because antibody-mediated blockade of its ligand, Programmed Death Ligand 1 (PD-L1) is sufficient to improve T cell function and reduce viral replication in animal models. Reversing PD-1 inhibition is therefore an attractive therapeutic target, but the cellular mechanisms by which PD-1 ligation results in T cell inhibition are not fully understood. PD-1 is thought to limit T cell activation by attenuating T cell receptor (TCR) signaling. It is not known whether PD-1 ligation also acts by upregulating genes in exhausted T cells that impair their function. Here, we analyzed gene-expression profiles from HIV-specific CD8+ T cells in patients with HIV and show that PD-1 coordinately upregulates a program of genes in exhausted CD8+ T cells from humans and mice. This program includes upregulation of basic leucine transcription factor, ATF-like (BATF), a transcription factor in the AP-1 family. Enforced expression of BATF was sufficient to impair T cell proliferation and cytokine secretion, while BATF knockdown reduced PD-1 inhibition. Silencing BATF in CD4+ and CD8+ T cells from chronic viremic patients rescued HIV-specific T cell function. Thus inhibitory receptors can cause T cell exhaustion by upregulating genes â such as BATF â that inhibit T cell function. We sorted HIV-specific CD8+ T cells from 18 progressors and 24 controllers, cohorts with a two-log difference in mean viral load
Project description:Chronic hepatitis C virus (HCV) infection is associated with CD8+ T-cell exhaustion characterized by limited effector functions and thus compromised anti-viral activity. Exhausted HCV-specific CD8+ T cells are comprised of memory-like and terminally exhausted CD8+ T-cell subsets. So far, little is not known about the molecular profile and fate of these cells after elimination of chronic antigen stimulation by direct acting antiviral therapy (DAA). Here, we report an antigen-driven molecular core signature underlying exhausted CD8+ T-cell subset heterogeneity in chronic viral infection with a progenitor/progeny relationship of memory-like and terminally exhausted HCV-specific CD8+ T cells via an intermediate stage. Furthermore, transcriptional profiling reveals that the memory-like cells remain after DAA-mediated cure while terminally exhausted HCV-specific CD8+ T-cell subsets are lost. Thus, the memory polarization of the overall HCV-specific CD8+ T-cell response after cure does not result from re-differentiation of exhausted T cells. Consequently, antigen elimination has little impact on the exhausted core signature of memory-like CD8+ T cells that remains clearly different from bona fide T-cell memory. These results identify a molecular signature of T-cell exhaustion that is imprinted like a chronic scar in HCV-specific CD8+ T cells even after HCV cure, highlighting the requirement of re-programming to elicit full effector potential of exhausted T cells.
Project description:Chronic hepatitis C virus (HCV) infection is associated with CD8+ T-cell exhaustion characterized by limited effector functions and thus compromised anti-viral activity. Exhausted HCV-specific CD8+ T cells are comprised of memory-like and terminally exhausted CD8+ T-cell subsets. So far, little is not known about the molecular profile and fate of these cells after elimination of chronic antigen stimulation by direct acting antiviral therapy (DAA). Here, we report an antigen-driven molecular core signature underlying exhausted CD8+ T-cell subset heterogeneity in chronic viral infection with a progenitor/progeny relationship of memory-like and terminally exhausted HCV-specific CD8+ T cells via an intermediate stage. Furthermore, transcriptional profiling reveals that the memory-like cells remain after DAA-mediated cure while terminally exhausted HCV-specific CD8+ T-cell subsets are lost. Thus, the memory polarization of the overall HCV-specific CD8+ T-cell response after cure does not result from re-differentiation of exhausted T cells. Consequently, antigen elimination has little impact on the exhausted core signature of memory-like CD8+ T cells that remains clearly different from bona fide T-cell memory. These results identify a molecular signature of T-cell exhaustion that is imprinted like a chronic scar in HCV-specific CD8+ T cells even after HCV cure, highlighting the requirement of re-programming to elicit full effector potential of exhausted T cells.
Project description:CD8+ T cells in chronic viral infections like HIV develop functional defects such as loss of IL-2 secretion and decreased proliferative potential that are collectively termed exhaustion1. Exhausted T cells express increased levels of multiple inhibitory receptors, such as Programmed Death 1 (PD-1). PD-1 inhibition contributes to impaired virus-specific T cell function in chronic infection because antibody-mediated blockade of its ligand, Programmed Death Ligand 1 (PD-L1) is sufficient to improve T cell function and reduce viral replication in animal models. Reversing PD-1 inhibition is therefore an attractive therapeutic target, but the cellular mechanisms by which PD-1 ligation results in T cell inhibition are not fully understood. PD-1 is thought to limit T cell activation by attenuating T cell receptor (TCR) signaling. It is not known whether PD-1 ligation also acts by upregulating genes in exhausted T cells that impair their function. Here, we analyzed gene-expression profiles from HIV-specific CD8+ T cells in patients with HIV and show that PD-1 coordinately upregulates a program of genes in exhausted CD8+ T cells from humans and mice. This program includes upregulation of basic leucine transcription factor, ATF-like (BATF), a transcription factor in the AP-1 family. Enforced expression of BATF was sufficient to impair T cell proliferation and cytokine secretion, while BATF knockdown reduced PD-1 inhibition. Silencing BATF in CD4+ and CD8+ T cells from chronic viremic patients rescued HIV-specific T cell function. Thus inhibitory receptors can cause T cell exhaustion by upregulating genes â such as BATF â that inhibit T cell function. PD-1 expressing Jurkat cells were cultured for 18 hours with beads coated with antibodies to CD3 and CD28, with our without an antibody to PD-1.
Project description:We investigated the effects of HIV infection on immune cell exhaustion at the transcriptomic level by analyzing single-cell RNA sequencing of peripheral blood mononuclear cells from four healthy subjects (37,847 cells) and six HIV-infected donors (28,610 cells). We identified nine immune cell clusters and eight T cell subclusters according to their unique gene expression programs; three of these (exhausted CD4+ and CD8+ T cells and interferon-responsive CD8+ T cells) were detected only in samples from HIV-infected donors. An inhibitory receptor KLRG1 was identified in the exhausted T cell populations and further characterized in HIV infected individuals. We identified a HIV-1 specific exhausted CD8+ T cell population expressing KLRG1, TIGIT, and T-betdimEomeshi markers. Ex-vivo antibody blockade of KLRG1 restored the function of HIV-specific exhausted CD8+ T cells demonstrating the contribution of KLRG1+ population to T cell exhaustion and providing an immunotherapy target to treat HIV chronic infection. Analysis of gene signatures also revealed impairment of B cell and NK cell function in HIV-infected donors. These data provide a comprehensive analysis of gene signatures associated with immune cell exhaustion during HIV infection, which could be useful in understanding exhaustion mechanisms and developing new cure therapies.
Project description:Bryostatin-1, a pharmacological agent from marine organisms, has been studied for HIV and cancer therapies due to its modulation of protein kinase C. In our previous study (Zhao M et al. Pharmacological research. 2019;139:524-34.), we found that bryostatin-1 downregulated inhibitory receptor PD-1 on activated CD8+ T cells from people with HIV. Since HIV-specific CD8+ T cells become functionally exhausted during chronic HIV infection and PD-1 expression is known to be related to the exhaustion state of these cells, we hypothesized that bryostatin-1 may modulate CD8+ T cell exhaustion. To test this, we generated in vitro exhausted OT-I CD8+ T cells as previously described (Zhao M et al PLoS Pathog. 16(6): e1008555) by repeatedly stimulating cells with OVA(257-264) peptide. Then we treated both exhausted CD8+ T cells (repeat peptide stimulated cells) and non-exhausted CD8+ T cells (single peptide stimulated cells) with bryostatin-1 for 3 days. We found that bryostatin-1 decreased exhaustion-associated markers and improved the functionality of exhausted CD8+ T cells. To investigate the underlying mechanism of how bryostatin-1 exerts its effects on exhausted CD8+ T cells, we performed RNA-sequencing (RNA-seq) on in vitro exhausted OT- I CD8+ T cells which were treated with bryostatin-1 or DMSO, with single peptide stimulated cells as non-exhausted controls. Taken together, our study demonstrate bryostatin-1's effect on exhausted CD8+ T cells and bryostatin-1's potential in enhancing T cell immunity against chronic infection or cancer.
Project description:T cell dysfunction is an important feature of many chronic viral infections. In particular, it was shown that PD-1 regulates T cell dysfunction during chronic LCMV infection in mice and PD-1 high cells exhibit an intense exhausted gene signature. These findings were extended to human chronic infections such as HIV, HCV and HBV. However, it is not known if PD-1 high cells of healthy humans have the traits of exhausted cells. In this study, we provide a comprehensive description of phenotype, function and gene expression profiles of PD-1 high versus PD-1 low CD8 T cells in the peripheral blood of healthy human adults as following: 1) The percentage of naive and memory CD8 T cells varied widely in the peripheral blood cells of healthy humans and PD-1 was expressed by the memory CD8 T cells. 2) PD-1 high CD8 T cells in healthy humans did not significantly correlated with the PD-1 high exhausted gene signature of HIV specific human CD8 T cells or chronic LCMV specific CD8 T cells from mice. 3) PD-1 expression did not directly affect the ability of CD8 T cells to secrete cytokines in healthy adults. 4) PD-1 was expressed by the effector memory (TEM) compared to ‘terminally differentiated effector’ (TEMRA) CD8 T cells. 5) Finally, an interesting inverse relationship between CD45RA and PD-1 expression was observed. We used highly purified PD-1 high and PD-1 low from six healthy adult individuals and naive CD8 T cell populations from four of those individuals for gene expression studies
Project description:Chronic viral infections represent a major public health problem. Although it is well understood that neonates and adults respond differently to chronic viral infections (HIV, HCV), the underlying mechanisms remain poorly understood. In this study, we transferred neonatal and adult CD8+ T cells into a mouse model of chronic infection (LCMV clone 13) and dissected out the key cell-intrinsic differences that alter their ability to protect the host. Interestingly, we found that neonatal CD8+ T cells preferentially become effector cells early in chronic infection when compared to adult CD8+ T cells, and resist commitment to the exhausted differentiation trajectory. Further, neonatal CD8+ T cells are preferentially maintained as stem-like exhausted progenitors rather than terminally exhausted cells during the chronic phase of infection. The altered differentiation trajectories of neonatal and adult CD8+ T cells is functionally significant, for the neonatal cells protect from viral replication. Together, our work demonstrates how cell-intrinsic differences between neonatal and adult CD8+ T cells influences key cell fate decisions during chronic infection.
Project description:Chronic viral infections represent a major public health problem. Although it is well understood that neonates and adults respond differently to chronic viral infections (HIV, HCV), the underlying mechanisms remain poorly understood. In this study, we transferred neonatal and adult CD8+ T cells into a mouse model of chronic infection (LCMV clone 13) and dissected out the key cell-intrinsic differences that alter their ability to protect the host. Interestingly, we found that neonatal CD8+ T cells preferentially become effector cells early in chronic infection when compared to adult CD8+ T cells, and resist commitment to the exhausted differentiation trajectory. Further, neonatal CD8+ T cells are preferentially maintained as stem-like exhausted progenitors rather than terminally exhausted cells during the chronic phase of infection. The altered differentiation trajectories of neonatal and adult CD8+ T cells is functionally significant, for the neonatal cells protect from viral replication at the cost of early-onset immunopathology. Together, our work demonstrates how cell-intrinsic differences between neonatal and adult CD8+ T cells influences key cell fate decisions during chronic infection.