scholarly journals Phenotypic and functional differences of HBV core-specific versus HBV polymerase-specific CD8+ T cells in chronically HBV-infected patients with low viral load

Gut ◽  
2019 ◽  
Vol 68 (5) ◽  
pp. 905-915 ◽  
Author(s):  
Anita Schuch ◽  
Elahe Salimi Alizei ◽  
Kathrin Heim ◽  
Dominik Wieland ◽  
Michael Muthamia Kiraithe ◽  
...  
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Cd8 T Cells ◽  
Molecular Mechanisms ◽  
T Cell Responses ◽  
T Cell Exhaustion ◽  
Detection Rates ◽  
Cell Exhaustion ◽  
Cell Responses

ObjectiveA hallmark of chronic HBV (cHBV) infection is the presence of impaired HBV-specific CD8+ T cell responses. Functional T cell exhaustion induced by persistent antigen stimulation is considered a major mechanism underlying this impairment. However, due to their low frequencies in chronic infection, it is currently unknown whether HBV-specific CD8+ T cells targeting different epitopes are similarly impaired and share molecular profiles indicative of T cell exhaustion.DesignBy applying peptide-loaded MHC I tetramer-based enrichment, we could detect HBV-specific CD8+ T cells targeting epitopes in the HBV core and the polymerase proteins in the majority of 85 tested cHBV patients with low viral loads. Lower detection rates were obtained for envelope-specific CD8+ T cells. Subsequently, we performed phenotypic and functional in-depth analyses.ResultsHBV-specific CD8+ T cells are not terminally exhausted but rather exhibit a memory-like phenotype in patients with low viral load possibly reflecting weak ongoing cognate antigen recognition. Moreover, HBV-specific CD8+ T cells targeting core versus polymerase epitopes significantly differed in frequency, phenotype and function. In particular, in comparison with core-specific CD8+ T cells, a higher frequency of polymerase-specific CD8+ T cells expressed CD38, KLRG1 and Eomes accompanied by low T-bet expression and downregulated CD127 indicative of a more severe T cell exhaustion. In addition, polymerase-specific CD8+ T cells exhibited a reduced expansion capacity that was linked to a dysbalanced TCF1/BCL2 expression.ConclusionsOverall, the molecular mechanisms underlying impaired T cell responses differ with respect to the targeted HBV antigens. These results have potential implications for immunotherapeutic approaches in HBV cure.

scholarly journals Tumor-Specific T Cells in Human Merkel Cell Carcinomas: A Possible Role for Tregs and T-Cell Exhaustion in Reducing T-Cell Responses

2013 ◽  
Vol 133 (7) ◽  
pp. 1879-1889 ◽  
Author(s):  
Mitra Dowlatshahi ◽  
Victor Huang ◽  
Ahmed E. Gehad ◽  
Ying Jiang ◽  
Adam Calarese ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Responses ◽  
T Cell Exhaustion ◽  
Merkel Cell ◽  
Cell Exhaustion ◽  
Cell Responses

scholarly journals Bovine Immunoinhibitory Receptors Contribute to Suppression of Mycobacterium avium subsp. paratuberculosis-Specific T-Cell Responses

2015 ◽  
Vol 84 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Tomohiro Okagawa ◽  
Satoru Konnai ◽  
Asami Nishimori ◽  
Ryoyo Ikebuchi ◽  
Seiko Mizorogi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mycobacterium Avium ◽  
T Cell Responses ◽  
T Cell Exhaustion ◽  
Content Type ◽  
Cell Exhaustion ◽  
Mhc Ii ◽  
Cell Responses ◽  
Ifn Γ

Johne's disease (paratuberculosis) is a chronic enteritis in cattle that is caused by intracellular infection withMycobacterium aviumsubsp.paratuberculosis. This infection is characterized by the functional exhaustion of T-cell responses toM. aviumsubsp.paratuberculosisantigens during late subclinical and clinical stages, presumably facilitating the persistence of this bacterium and the formation of clinical lesions. However, the mechanisms underlying T-cell exhaustion in Johne's disease are poorly understood. Thus, we performed expression and functional analyses of the immunoinhibitory molecules programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) and lymphocyte activation gene 3 (LAG-3)/major histocompatibility complex class II (MHC-II) inM. aviumsubsp.paratuberculosis-infected cattle during the late subclinical stage. Flow cytometric analyses revealed the upregulation of PD-1 and LAG-3 in T cells in infected animals, which suffered progressive suppression of interferon gamma (IFN-γ) responses to theM. aviumsubsp.paratuberculosisantigen. In addition, PD-L1 and MHC-II were expressed on macrophages from infected animals, consistent with PD-1 and LAG-3 pathways contributing to the suppression of IFN-γ responses during the subclinical stages ofM. aviumsubsp.paratuberculosisinfection. Furthermore, dual blockade of PD-L1 and LAG-3 enhancedM. aviumsubsp.paratuberculosis-specific IFN-γ responses in blood from infected animals, andin vitroLAG-3 blockade enhanced IFN-γ production fromM. aviumsubsp.paratuberculosis-specific CD4+and CD8+T cells. Taken together, the present data indicate thatM. aviumsubsp.paratuberculosis-specific T-cell exhaustion is in part mediated by PD-1/PD-L1 and LAG-3/MHC-II interactions and that LAG-3 is a molecular target for the control ofM. aviumsubsp.paratuberculosis-specific T-cell responses.

scholarly journals Defining Kinetic Properties of HIV-Specific CD8+ T-cell Responses in Acute Infection

2019 ◽  
Author(s):  
Yiding Yang ◽  
Vitaly V. Ganusov
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Cd8 T Cells ◽  
Chronic Infection ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
Average Viral Load

Multiple lines of evidence indicate that CD8$^+$ T cells are important in the control of HIV-1 (HIV) replication. However, CD8$^+$ T cells induced by natural infection cannot eliminate the virus or reduce viral loads to acceptably low levels in most infected individuals. Understanding the basic quantitative features of CD8$^+$ T-cell responses induced during the course of HIV infection may therefore inform us about the limits that HIV vaccines, which aim to induce protective CD8$^+$ T-cell responses, must exceed. Using previously published experimental data from a cohort of HIV-infected individuals with sampling times from acute to chronic infection we defined the quantitative properties of CD8$^+$ T-cell responses to the whole HIV proteome. In contrast with a commonly held view, we found that the relative number of HIV-specific CD8$^+$ T-cell responses (response breadth) changed little over the course of infection (first 400 days post-infection), with moderate but statistically significant changes occurring only during the first 35 symptomatic days. This challenges the idea that a change in the T-cell response breadth over time is responsible for the slow speed of viral escape from CD8$^+$ T cells in the chronic infection. The breadth of HIV-specific CD8$^+$ T-cell responses was not correlated with the average viral load for our small cohort of patients. Metrics of relative immunodominance of HIV-specific CD8$^+$ T-cell responses such as Shannon entropy or the Evenness index were also not significantly correlated with the average viral load. Our mathematical-model-driven analysis suggested extremely slow expansion kinetics for the majority of HIV-specific CD8$^+$ T-cell responses and the presence of intra- and interclonal competition between multiple CD8$^+$ T-cell responses; such competition may limit the magnitude of CD8$^+$ T-cell responses, specific to different epitopes, and the overall number of T-cell responses induced by vaccination. Further understanding of mechanisms underlying interactions between the virus and virus-specific CD8$^+$ T-cell response will be instrumental in determining which T-cell-based vaccines will induce T-cell responses providing durable protection against HIV infection.

scholarly journals Immunotherapeutic effects of IL-7 during a chronic viral infection in mice

Blood ◽  
2011 ◽  
Vol 117 (19) ◽  
pp. 5123-5132 ◽  
Author(s):  
Som G. Nanjappa ◽  
Eui Ho Kim ◽  
M. Suresh
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Cd8 T Cells ◽  
Viral Infections ◽  
T Cell Responses ◽  
Duration Of Treatment ◽  
Viral Control ◽  
Cell Responses ◽  
Chronic Viral Infections

AbstractViral persistence during chronic viral infections is associated with a progressive loss of T-cell effector function called functional exhaustion. There is therefore a need to develop immunotherapies to remediate the functional deficits of T cells during these infections. We investigated the immunotherapeutic effects of IL-7 during chronic lymphocytic choriomeningitis virus infection in mice. Our results showed that the effects of IL-7 on T cells depend on the viral load, timing, and duration of treatment during the course of the infection. We document that the effectiveness of IL-7 was constrained by high viral load early in the infection, but treatment for at least 3 weeks during declining viral titers mitigated the programmed contraction of CD8 T cells, markedly enhanced the number of high-quality polyfunctional virus-specific CD8 T cells with a nonexhausted phenotype, and accelerated viral control. Mechanistically, the enhancement of CD8 T-cell responses by IL-7 was associated with increased proliferation and induction of Bcl-2, but not with altered levels of PD-1 or Cbl-b. In summary, our results strongly suggest that IL-7 therapy is a potential strategy to bolster the quality and quantity of T-cell responses in patients with chronic viral infections.

scholarly journals Impact of Epitope Escape on PD-1 Expression and CD8 T-Cell Exhaustion during Chronic Infection

2009 ◽  
Vol 83 (9) ◽  
pp. 4386-4394 ◽  
Author(s):  
Joseph N. Blattman ◽  
E. John Wherry ◽  
Sang-Jun Ha ◽  
Robbert G. van der Most ◽  
Rafi Ahmed
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Viral Infections ◽  
Viral Clearance ◽  
T Cell Exhaustion ◽  
Wild Type ◽  
Cell Exhaustion ◽  
Cell Responses ◽  
Functional Inactivation

ABSTRACT During some persistent viral infections, virus-specific T-cell responses wane due to the antigen-specific deletion or functional inactivation (i.e., exhaustion) of responding CD8 T cells. T-cell exhaustion often correlates with high viral load and is associated with the expression of the inhibitory receptor PD-1. In other infections, functional T cells are observed despite high levels of pathogen persistence. The reasons for these different T-cell fates during chronic viral infections are not clear. Here, we tracked the fate of virus-specific CD8 T cells in lymphocytic choriomeningitis virus (LCMV)-infected mice during viral clearance, the persistence of wild-type virus, or the selection and persistence of a viral variant that abrogates the presentation of a single epitope. Viral clearance results in PD-1lo functional virus-specific CD8 T cells, while the persistence of wild-type LCMV results in high PD-1 levels and T-cell exhaustion. However, following the emergence of a GP35V→A variant virus that abrogates the presentation of the GP33 epitope, GP33-specific CD8 T cells remained functional, continued to show low levels of PD-1, and reexpressed CD127, a marker of memory T-cell differentiation. In the same animals and under identical environmental conditions, CD8 T cells recognizing nonmutated viral epitopes became physically deleted or were PD-1hi and nonfunctional. Thus, the upregulation of PD-1 and the functional inactivation of virus-specific T cells during chronic viral infection is dependent upon continued epitope recognition. These data suggest that optimal strategies for vaccination should induce high-magnitude broadly specific T-cell responses that prevent cytotoxic T-lymphocyte escape and highlight the need to evaluate the function of vaccine-induced T cells in the context of antigens presented during virus persistence.

scholarly journals NFAT-dependent and -independent exhaustion circuits program maternal CD8 T cell hypofunction in pregnancy

2021 ◽  
Vol 219 (1) ◽  
Author(s):  
Emma L. Lewis ◽  
Rong Xu ◽  
Jean-Christophe Beltra ◽  
Shin Foong Ngiow ◽  
Jordana Cohen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Ribosomal Proteins ◽  
Molecular Mechanisms ◽  
Cd8 T Cell ◽  
T Cell Exhaustion ◽  
Cell Exhaustion ◽  
Fetal Antigen ◽  
In Pregnancy

Pregnancy is a common immunization event, but the molecular mechanisms and immunological consequences provoked by pregnancy remain largely unknown. We used mouse models and human transplant registry data to reveal that pregnancy induced exhausted CD8 T cells (Preg-TEX), which associated with prolonged allograft survival. Maternal CD8 T cells shared features of exhaustion with CD8 T cells from cancer and chronic infection, including transcriptional down-regulation of ribosomal proteins and up-regulation of TOX and inhibitory receptors. Similar to other models of T cell exhaustion, NFAT-dependent elements of the exhaustion program were induced by fetal antigen in pregnancy, whereas NFAT-independent elements did not require fetal antigen. Despite using conserved molecular circuitry, Preg-TEX cells differed from TEX cells in chronic viral infection with respect to magnitude and dependency of T cell hypofunction on NFAT-independent signals. Altogether, these data reveal the molecular mechanisms and clinical consequences of maternal CD8 T cell hypofunction and identify pregnancy as a previously unappreciated context in which T cell exhaustion may occur.

scholarly journals CLL Is Associated with Development of Subclinical Cytomegalovirus Viraemia and Accumulation of Large Populations of “exhausted” CMV-Specific CD4+ T Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3290-3290
Author(s):  
Helen M Parry ◽  
Natasha Cutmore ◽  
Nikhil Mirajkar ◽  
Annette Pachnio ◽  
Tina McSkeane ◽  
...  
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Effector Memory ◽  
T Cell Exhaustion ◽  
Cell Exhaustion

Abstract Chronic Lymphocytic Leukaemia (CLL) is associated with T cell dysfunction and increased expression of markers of T cell exhaustion. Cytomegalovirus is a common herpesvirus infection and is associated with development of accelerated immune senescence in older adults. Within patients with CLL, CMV leads to marked expansion of virus-specific CD4 and CD8 T cells and development of oligoclonal T cell populations. However these features are not known to be associated with clinical symptoms and CMV viral load remains essentially undetectable by conventional qPCR. In this study we used digital PCR to determine CMV viral load in patients with CLL and correlated this with the magnitude and phenotype of the CMV-specific T cell immune response. In particular, we utilised HLA class II tetramers for the first time, in order to assess the contribution of CMV-specific T cell populations to the profile of T cell exhaustion seen in this disease. 68 CMV-seropositive CLL patients and 19 age-matched healthy donors (HD) were recruited for study. All patients were either untreated or had not received chemotherapy for at least 6 months. CMV viral load was determined within purified monocyte populations using a digital droplet PCR method. Viral load per monocyte was increased in CLL patients compared to HD (p=0.04), with the highest viral loads detected in stage C patients. In order to investigate the CMV-specific immune response, nine HLA class I tetramers were generated, containing viral epitopes from pp65, pp50 and IE-1, and two class II tetramers were also available, with epitopes from glycoprotein B and pp65. CMV-specific CD4 T cell responses were increased in CLL patients (n=14) compared to HD (n=11) (4.1 % vs. 0.9 %; p=0.049). Remarkably, in one patient more than half (50.9%) of all CD4 T cells were directed against a single CMV epitope. CD4 CMV-specific T cells were nearly always effector memory in phenotype (78%), somewhat in contrast to CD8 populations where the memory phenotype is split between effector memory (CCR7-, CD45RA-) and terminally differentiated memory cells (CCR7-, CD45RA+). PD1 is an important marker of T cell exhaustion and expression was increased on both CD8 T cells (16.9% Vs 9.6%; p=0.003); and CD4 T cells (16.2 % Vs 8.7 %; p=0.0007) in CLL patients compared to HD. Interestingly, PD1 expression was much higher on CMV-specific CD4 T cells compared to the total CD4 T cell repertoire (50.6% Vs 21%; p=0.01), whereas the opposite profile was observed in relation to CD8 populations. CMV-specific CD4 T cells demonstrated a Th1 cytotoxic phenotype with production of TNF-alpha, IFN-y and Granzyme B. Production of IFN-y and TNF-alpha was reduced in PD1+ populations, consistent with an exhausted phenotype. No CD25+FoxP3 + regulatory T cells were observed within the CMV-specific CD4 T cell population which is of interest given the well documented expansion of this population in patients with CLL. In order to investigate the replicative history of CMV-specific T cells we investigated the telomere length of antigen-specific cells using single cell telomere length analysis. CMV-specific cells had markedly shortened telomere lengths compared to background CD4 and CD8 T cells, with the mean difference of 0.911 kb (maximum 1.836 kb) indicating that they have undergone extensive proliferation in vivo. This work is the first to use digital PCR to measure the subclinical CMV load within peripheral blood and also to examine CMV-specific CD4 T cells using HLA class II tetramers. Our results indicate that immune control of CMV viral load is impaired during the clinical progression of CLL and that a proportion of virus-specific CD4 T cells show signs of exhaustion. These data may reflect ‘cross presentation’ of viral protein by B-CLL tumour cells, which are known to have poor capacity for antigen presentation. The potential clinical importance of these observations is now being addressed. Disclosures No relevant conflicts of interest to declare.

scholarly journals Cooperation of PD-1 and LAG-3 Contributes to T-Cell Exhaustion in Anaplasma marginale-Infected Cattle

2016 ◽  
Vol 84 (10) ◽  
pp. 2779-2790 ◽  
Author(s):  
Tomohiro Okagawa ◽  
Satoru Konnai ◽  
James R. Deringer ◽  
Massaro W. Ueti ◽  
Glen A. Scoles ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Outer Membrane Proteins ◽  
T Cell Responses ◽  
Anaplasma Marginale ◽  
T Cell Exhaustion ◽  
Content Type ◽  
Cell Exhaustion ◽  
Cell Responses ◽  
Ifn Γ

The CD4+T-cell response is central for the control ofAnaplasma marginaleinfection in cattle. However, the infection induces a functional exhaustion of antigen-specific CD4+T cells in cattle immunized withA. marginaleouter membrane proteins or purified outer membranes (OMs), which presumably facilitates the persistence of this rickettsia. In the present study, we hypothesize that T-cell exhaustion following infection is induced by the upregulation of immunoinhibitory receptors on T cells, such as programmed death 1 (PD-1) and lymphocyte activation gene 3 (LAG-3). OM-specific T-cell responses and the kinetics of PD-1-positive (PD-1+) LAG-3+exhausted T cells were monitored inA. marginale-challenged cattle previously immunized with OMs. Consistent with data from previous studies, OM-specific proliferation of peripheral blood mononuclear cells (PBMCs) and interferon gamma (IFN-γ) production were significantly suppressed in challenged animals by 5 weeks postinfection (wpi). In addition, bacteremia and anemia also peaked in these animals at 5 wpi. Flow cytometric analysis revealed that the percentage of PD-1+LAG-3+T cells in the CD4+, CD8+, and γδ T-cell populations gradually increased and also peaked at 5 wpi. A large increase in the percentage of LAG-3+γδ T cells was also observed. Importantly,in vitro, the combined blockade of the PD-1 and LAG-3 pathways partially restored OM-specific PBMC proliferation and IFN-γ production at 5 wpi. Taken together, these results indicate that coexpression of PD-1 and LAG-3 on T cells contributes to the rapid exhaustion ofA. marginale-specific T cells following infection and that these immunoinhibitory receptors regulate T-cell responses during bovine anaplasmosis.

scholarly journals Defining Kinetic Properties of HIV-Specific CD8+ T-Cell Responses in Acute Infection

2019 ◽  
Vol 7 (3) ◽  
pp. 69 ◽  
Author(s):  
Yiding Yang ◽  
Vitaly Ganusov
Keyword(s):  
T Cells ◽  
Viral Load ◽  
T Cell ◽  
Cd8 T Cells ◽  
Chronic Infection ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
Average Viral Load

Multiple lines of evidence indicate that CD8 + T cells are important in the control of HIV-1 (HIV) replication. However, CD8 + T cells induced by natural infection cannot eliminate the virus or reduce viral loads to acceptably low levels in most infected individuals. Understanding the basic quantitative features of CD8 + T-cell responses induced during HIV infection may therefore inform us about the limits that HIV vaccines, which aim to induce protective CD8 + T-cell responses, must exceed. Using previously published experimental data from a cohort of HIV-infected individuals with sampling times from acute to chronic infection we defined the quantitative properties of CD8 + T-cell responses to the whole HIV proteome. In contrast with a commonly held view, we found that the relative number of HIV-specific CD8 + T-cell responses (response breadth) changed little over the course of infection (first 400 days post-infection), with moderate but statistically significant changes occurring only during the first 35 symptomatic days. This challenges the idea that a change in the T-cell response breadth over time is responsible for the slow speed of viral escape from CD8 + T cells in the chronic infection. The breadth of HIV-specific CD8 + T-cell responses was not correlated with the average viral load for our small cohort of patients. Metrics of relative immunodominance of HIV-specific CD8 + T-cell responses such as Shannon entropy or the Evenness index were also not significantly correlated with the average viral load. Our mathematical-model-driven analysis suggested extremely slow expansion kinetics for the majority of HIV-specific CD8 + T-cell responses and the presence of intra- and interclonal competition between multiple CD8 + T-cell responses; such competition may limit the magnitude of CD8 + T-cell responses, specific to different epitopes, and the overall number of T-cell responses induced by vaccination. Further understanding of mechanisms underlying interactions between the virus and virus-specific CD8 + T-cell response will be instrumental in determining which T-cell-based vaccines will induce T-cell responses providing durable protection against HIV infection.

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