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1.
Nat Immunol ; 22(2): 229-239, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33398179

RESUMO

In chronic hepatitis C virus (HCV) infection, exhausted HCV-specific CD8+ T cells comprise memory-like and terminally exhausted subsets. However, little is known about the molecular profile and fate of these two subsets after the elimination of chronic antigen stimulation by direct-acting antiviral (DAA) therapy. Here, we report a progenitor-progeny relationship between memory-like and terminally exhausted HCV-specific CD8+ T cells via an intermediate subset. Single-cell transcriptomics implicated that memory-like cells are maintained and terminally exhausted cells are lost after DAA-mediated cure, resulting in a memory polarization of the overall HCV-specific CD8+ T cell response. However, an exhausted core signature of memory-like CD8+ T cells was still detectable, including, to a smaller extent, in HCV-specific CD8+ T cells targeting variant epitopes. These results identify a molecular signature of T cell exhaustion that is maintained as a chronic scar in HCV-specific CD8+ T cells even after the cessation of chronic antigen stimulation.

2.
Sci Immunol ; 6(55)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452106

RESUMO

The developmental origins of memory T cells remain incompletely understood. During the expansion phase of acute viral infection, we identified a distinct subset of virus-specific CD8+ T cells that possessed distinct characteristics including expression of CD62L, T cell factor 1 (TCF-1), and Eomesodermin; relative quiescence; expression of activation markers; and features of limited effector differentiation. These cells were a quantitatively minor subpopulation of the TCF-1+ pool and exhibited self-renewal, heightened DNA damage surveillance activity, and preferential long-term recall capacity. Despite features of memory and somewhat restrained proliferation during the expansion phase, this subset displayed evidence of stronger TCR signaling than other responding CD8+ T cells, coupled with elevated expression of multiple inhibitory receptors including programmed cell death 1 (PD-1), lymphocyte activating gene 3 (LAG-3), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), CD5, and CD160. Genetic ablation of PD-1 and LAG-3 compromised the formation of this CD62Lhi TCF-1+ subset and subsequent CD8+ T cell memory. Although central memory phenotype CD8+ T cells were formed in the absence of these cells, subsequent memory CD8+ T cell recall responses were compromised. Together, these results identify an important link between genome integrity maintenance and CD8+ T cell memory. Moreover, the data indicate a role for inhibitory receptors in preserving key memory CD8+ T cell precursors during initial activation and differentiation. Identification of this rare subpopulation within the memory CD8+ T cell precursor pool may help reconcile models of the developmental origin of long-term CD8+ T cell memory.

3.
J Exp Med ; 218(2)2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33170215

RESUMO

The identification and characterization of rare immune cell populations in humans can be facilitated by their growth advantage in the context of specific genetic diseases. Here, we use autoimmune lymphoproliferative syndrome to identify a population of FAS-controlled TCRαß+ T cells. They include CD4+, CD8+, and double-negative T cells and can be defined by a CD38+CD45RA+T-BET- expression pattern. These unconventional T cells are present in healthy individuals, are generated before birth, are enriched in lymphoid tissue, and do not expand during acute viral infection. They are characterized by a unique molecular signature that is unambiguously different from other known T cell differentiation subsets and independent of CD4 or CD8 expression. Functionally, FAS-controlled T cells represent highly proliferative, noncytotoxic T cells with an IL-10 cytokine bias. Mechanistically, regulation of this physiological population is mediated by FAS and CTLA4 signaling, and its survival is enhanced by mTOR and STAT3 signals. Genetic alterations in these pathways result in expansion of FAS-controlled T cells, which can cause significant lymphoproliferative disease.

4.
Nat Med ; 2020 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-33184509

RESUMO

Emerging data indicate that SARS-CoV-2-specific CD8+ T cells targeting different viral proteins are detectable in up to 70% of convalescent individuals1-5. However, very little information is currently available about the abundance, phenotype, functional capacity and fate of pre-existing and induced SARS-CoV-2-specific CD8+ T cell responses during the natural course of SARS-CoV-2 infection. Here, we define a set of optimal and dominant SARS-CoV-2-specific CD8+ T cell epitopes. We also perform a high-resolution ex vivo analysis of pre-existing and induced SARS-CoV-2-specific CD8+ T cells, applying peptide-loaded major histocompatibility complex class I (pMHCI) tetramer technology. We observe rapid induction, prolonged contraction and emergence of heterogeneous and functionally competent cross-reactive and induced memory CD8+ T cell responses in cross-sectionally analyzed individuals with mild disease following SARS-CoV-2 infection and three individuals longitudinally assessed for their T cells pre- and post-SARS-CoV-2 infection. SARS-CoV-2-specific memory CD8+ T cells exhibited functional characteristics comparable to influenza-specific CD8+ T cells and were detectable in SARS-CoV-2 convalescent individuals who were seronegative for anti-SARS-CoV-2 antibodies targeting spike (S) and nucleoprotein (N). These results define cross-reactive and induced SARS-CoV-2-specific CD8+ T cell responses as potentially important determinants of immune protection in mild SARS-CoV-2 infection.

5.
J Hepatol ; 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33211012

RESUMO

BACKGROUND AND AIMS: Patients with decompensated liver cirrhosis suffer from recurrent infections and inadequate responses to prophylactic vaccinations. However, many patients present with hypergammaglobulinemia (HGG), indicating a sustained ability to generate antibody responses. As follicular T helper (Tfh) cells are central facilitators of humoral immunity by providing B cell help, we hypothesized that Tfh cell responses may be altered in advanced liver disease and aimed to identify underlying mechanisms. METHODS: Tfh, regulatory T (Treg) cells and B cells, circulating cytokines and immunoglobulins were analyzed in cohorts of patients with compensated (n = 37) and decompensated cirrhosis (n = 82) and in non-cirrhotic controls (n = 45). Intrahepatic T cells were analyzed in 8 decompensated patients. The influence of IL-2 on Tfh cell function was evaluated in vitro, including Tfh cell cloning and T cell-B cell co-cultures with clones and primary tonsil-derived Tfh cells. RESULTS: Tfh cell frequencies were reduced in patients with decompensated liver cirrhosis with phenotypic signatures indicative of increased IL-2 signaling. Soluble IL-2 receptor (sCD25) was elevated in these patients and CD4 T cells were more responsive to IL-2 signaling, as characterized by STAT5 phosphorylation. IL-2 exposure in vitro diminished the Tfh phenotype and resulted in impaired Tfh helper function in co-culture experiments with naïve B cells. Tfh cells were barely detectable in cirrhotic livers. IL-2 signatures on Tfh cells in decompensated patients correlated with immunoglobulin levels, which were found to be associated with improved survival. CONCLUSIONS: Tfh cell impairment represents a previously underestimated feature of cirrhosis-associated immune dysfunction that is driven by IL-2. Presence of HGG in decompensated patients predicts an intact Tfh cell compartment and is associated with a favorable outcome.

6.
Gut ; 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097558

RESUMO

OBJECTIVE: Chronic hepatitis B virus (HBV) infection is characterised by HBV-specific CD8+ T cell dysfunction that has been linked to Tcell exhaustion, a distinct differentiation programme associated with persisting antigen recognition. Recently, Thymocyte Selection-Associated High Mobility Group Box (TOX) was identified as master regulator of CD8+ T cell exhaustion. Here, we addressed the role of TOX in HBV-specific CD8+ T cell dysfunction associated with different clinical phases of infection. DESIGN: We investigated TOX expression in HBV-specific CD8+ T cells from 53 HLA-A*01:01, HLA-A*11:01 and HLA-A*02:01 positive patients from different HBV infection phases and compared it to hepatitis C virus (HCV)-specific, cytomegalovirus (CMV)-specific, Epstein-Barr virus (EBV)-specific and influenza virus (FLU)-specific CD8+ T cells. Phenotypic and functional analyses of virus-specific CD8+ T cells were performed after peptide-loaded tetramer-enrichment and peptide-specific expansion. RESULTS: Our results show that TOX expression in HBV-specific CD8+ T cells is linked to chronic antigen stimulation, correlates with viral load and is associated with phenotypic and functional characteristics of T-cell exhaustion. In contrast, similar TOX expression in EBV-specific and CMV-specific CD8+ T cells is not linked to T-cell dysfunction suggesting different underlying programmes. TOX expression in HBV-specific CD8+ T cells is also affected by targeted antigens, for example, core versus polymerase. In HBV-specific CD8+ T cells, TOX expression is maintained after spontaneous or therapy-mediated viral control in chronic but not self-limiting acute HBV infection indicating a permanent molecular imprint after chronic but not temporary stimulation. CONCLUSION: Our data highlight TOX as biomarker specific for dysfunctional virus-specific CD8+ T cells in the context of an actively persisting infection.

7.
Sci Immunol ; 5(49)2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32680953

RESUMO

LAG3 cleavage from conventional CD4+ T cells, but not CD8+ T cells, is required for effective PD-1 blockade.

10.
Methods Mol Biol ; 2111: 1-20, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31933194

RESUMO

T-cell diversity is multifactorial and includes variability in antigen specificity, differentiation, function, and cell-trafficking potential. Spectral overlap limits the ability of traditional flow cytometry to fully capture the diversity of T-cell subsets and function. The development of mass cytometry permits deep immunoprofiling of T-cell subsets, activation state, and function simultaneously from even small volumes of blood. This chapter describes our methods for mass cytometry and high-throughput data analysis of T cells in patient cohorts. We provide a pipeline that includes practical considerations when customizing a panel for mass cytometry. We also provide protocols for the conjugation and titration of metal-labeled antibodies (including two T-cell panels) and a staining procedure. Finally, with the aim to support translational science, we provide R scripts that contain a detailed workflow for initial evaluation of high-dimensional data generated from cohorts of patients.

11.
J Clin Invest ; 130(2): 998-1009, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31697649

RESUMO

BACKGROUNDChronic hepatitis C virus (HCV) infection is characterized by a severe impairment of HCV-specific CD4+ T cell help that is driven by chronic antigen stimulation. We aimed to study the fate of HCV-specific CD4+ T cells after virus elimination.METHODSHCV-specific CD4+ T cell responses were longitudinally analyzed using MHC class II tetramer technology, multicolor flow cytometry, and RNA sequencing in a cohort of patients chronically infected with HCV undergoing therapy with direct-acting antivirals. In addition, HCV-specific neutralizing antibodies and CXCL13 levels were analyzed.RESULTSWe observed that the frequency of HCV-specific CD4+ T cells increased within 2 weeks after initiating direct-acting antiviral therapy. Multicolor flow cytometry revealed a downregulation of exhaustion and activation markers and an upregulation of memory-associated markers. Although cells with a Th1 phenotype were the predominant subset at baseline, cells with phenotypic and transcriptional characteristics of follicular T helper cells increasingly shaped the circulating HCV-specific CD4+ T cell repertoire, suggesting antigen-independent survival of this subset. These changes were accompanied by a decline of HCV-specific neutralizing antibodies and the germinal center activity.CONCLUSIONWe identified a population of HCV-specific CD4+ T cells with a follicular T helper cell signature that is maintained after therapy-induced elimination of persistent infection and may constitute an important target population for vaccination efforts to prevent reinfection and immunotherapeutic approaches for persistent viral infections.FUNDINGDeutsche Forschungsgemeinschaft (DFG, German Research Foundation), the National Institute of Allergy and Infectious Diseases (NIAID), the European Union, the Berta-Ottenstein-Programme for Advanced Clinician Scientists, and the ANRS.


Assuntos
Hepacivirus/imunologia , Hepatite C Crônica/imunologia , Antivirais/administração & dosagem , Feminino , Citometria de Fluxo , Seguimentos , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Células Th1/patologia
12.
Immunity ; 51(5): 840-855.e5, 2019 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-31606264

RESUMO

TCF-1 is a key transcription factor in progenitor exhausted CD8 T cells (Tex). Moreover, this Tex cell subset mediates responses to PD-1 checkpoint pathway blockade. However, the role of the transcription factor TCF-1 in early fate decisions and initial generation of Tex cells is unclear. Single-cell RNA sequencing (scRNA-seq) and lineage tracing identified a TCF-1+Ly108+PD-1+ CD8 T cell population that seeds development of mature Tex cells early during chronic infection. TCF-1 mediated the bifurcation between divergent fates, repressing development of terminal KLRG1Hi effectors while fostering KLRG1Lo Tex precursor cells, and PD-1 stabilized this TCF-1+ Tex precursor cell pool. TCF-1 mediated a T-bet-to-Eomes transcription factor transition in Tex precursors by promoting Eomes expression and drove c-Myb expression that controlled Bcl-2 and survival. These data define a role for TCF-1 in early-fate-bifurcation-driving Tex precursor cells and also identify PD-1 as a protector of this early TCF-1 subset.


Assuntos
Linfócitos T CD8-Positivos/metabolismo , Redes Reguladoras de Genes , Fator 1 de Transcrição de Linfócitos T/metabolismo , Transcrição Genética , Animais , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Doença Crônica , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Camundongos , Receptor de Morte Celular Programada 1/metabolismo , Fator 1 de Transcrição de Linfócitos T/genética , Viroses/genética , Viroses/imunologia , Viroses/virologia
13.
J Allergy Clin Immunol ; 144(6): 1660-1673, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31445098

RESUMO

BACKGROUND: Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numeric and/or functional TH cell alterations. The causes, interrelationships, and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia, autoantibody production, or both remain unclear. OBJECTIVE: We sought to determine how circulating CD4+ T cells are altered in CVID subjects with autoimmune cytopenias (AICs; CVID+AIC) and the causes of these derangements. METHODS: Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large and genetically diverse cohort of CVID subjects (n = 69) by using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection, and a suite of in vitro functional assays measuring naive T-cell differentiation, B-cell/T-cell cocultures, and regulatory T-cell suppression. RESULTS: Although CD4+ TH cell profiles from healthy donors and CVID subjects without AICs were virtually indistinguishable, T cells from CVID+AIC subjects exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and inducible T-cell costimulator ligand. The resulting enlarged circulating follicular helper T-cell population from CVID+AIC subjects provided efficient help to receptive healthy donor B cells but not unresponsive CVID B cells. Despite this, circulating follicular helper T cells from CVID+AIC subjects exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with regulatory T-cell suppression assays and were associated with autoantibody production. CONCLUSIONS: Endotoxemia is associated with early commitment to the follicular T-cell lineage in IgA-deficient CVID subjects, particularly those with AICs.


Assuntos
Linfócitos B/imunologia , Diferenciação Celular/imunologia , Imunodeficiência de Variável Comum/imunologia , Endotoxemia/imunologia , Deficiência de IgA/imunologia , Linfócitos T Reguladores/imunologia , Adolescente , Adulto , Linfócitos B/patologia , Criança , Pré-Escolar , Imunodeficiência de Variável Comum/patologia , Endotoxemia/patologia , Feminino , Humanos , Deficiência de IgA/patologia , Masculino , Pessoa de Meia-Idade , Linfócitos T Reguladores/patologia
14.
Nature ; 571(7764): 211-218, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31207603

RESUMO

Exhausted CD8+ T (Tex) cells in chronic infections and cancer have limited effector function, high co-expression of inhibitory receptors and extensive transcriptional changes compared with effector (Teff) or memory (Tmem) CD8+ T cells. Tex cells are important clinical targets of checkpoint blockade and other immunotherapies. Epigenetically, Tex cells are a distinct immune subset, with a unique chromatin landscape compared with Teff and Tmem cells. However, the mechanisms that govern the transcriptional and epigenetic development of Tex cells remain unknown. Here we identify the HMG-box transcription factor TOX as a central regulator of Tex cells in mice. TOX is largely dispensable for the formation of Teff and Tmem cells, but it is critical for exhaustion: in the absence of TOX, Tex cells do not form. TOX is induced by calcineurin and NFAT2, and operates in a feed-forward loop in which it becomes calcineurin-independent and sustained in Tex cells. Robust expression of TOX therefore results in commitment to Tex cells by translating persistent stimulation into a distinct Tex cell transcriptional and epigenetic developmental program.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Epistasia Genética , Proteínas de Homeodomínio/metabolismo , Transcrição Genética , Animais , Calcineurina/metabolismo , Sinalização do Cálcio , Retroalimentação Fisiológica , Feminino , Regulação da Expressão Gênica/imunologia , Genótipo , Memória Imunológica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fatores de Transcrição NFATC/metabolismo , Evasão Tumoral
15.
Cell Rep ; 27(7): 2063-2074.e5, 2019 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-31091446

RESUMO

Competition for nutrients like glucose can metabolically restrict T cells and contribute to their hyporesponsiveness during cancer. Metabolic adaptation to the surrounding microenvironment is therefore key for maintaining appropriate cell function. For instance, cancer cells use acetate as a substrate alternative to glucose to fuel metabolism and growth. Here, we show that acetate rescues effector function in glucose-restricted CD8+ T cells. Mechanistically, acetate promotes histone acetylation and chromatin accessibility and enhances IFN-γ gene transcription and cytokine production in an acetyl-CoA synthetase (ACSS)-dependent manner. Ex vivo acetate treatment increases IFN-γ production by exhausted T cells, whereas reducing ACSS expression in T cells impairs IFN-γ production by tumor-infiltrating lymphocytes and tumor clearance. Thus, hyporesponsive T cells can be epigenetically remodeled and reactivated by acetate, suggesting that pathways regulating the use of substrates alternative to glucose could be therapeutically targeted to promote T cell function during cancer.


Assuntos
Acetato-CoA Ligase/imunologia , Acetatos/imunologia , Linfócitos T CD8-Positivos/imunologia , Glucose/imunologia , Interferon gama/imunologia , Proteínas de Neoplasias/imunologia , Neoplasias Experimentais/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Linhagem Celular Tumoral , Humanos , Camundongos , Neoplasias Experimentais/patologia
16.
Nat Med ; 25(3): 454-461, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30804515

RESUMO

Immunologic responses to anti-PD-1 therapy in melanoma patients occur rapidly with pharmacodynamic T cell responses detectable in blood by 3 weeks. It is unclear, however, whether these early blood-based observations translate to the tumor microenvironment. We conducted a study of neoadjuvant/adjuvant anti-PD-1 therapy in stage III/IV melanoma. We hypothesized that immune reinvigoration in the tumor would be detectable at 3 weeks and that this response would correlate with disease-free survival. We identified a rapid and potent anti-tumor response, with 8 of 27 patients experiencing a complete or major pathological response after a single dose of anti-PD-1, all of whom remain disease free. These rapid pathologic and clinical responses were associated with accumulation of exhausted CD8 T cells in the tumor at 3 weeks, with reinvigoration in the blood observed as early as 1 week. Transcriptional analysis demonstrated a pretreatment immune signature (neoadjuvant response signature) that was associated with clinical benefit. In contrast, patients with disease recurrence displayed mechanisms of resistance including immune suppression, mutational escape, and/or tumor evolution. Neoadjuvant anti-PD-1 treatment is effective in high-risk resectable stage III/IV melanoma. Pathological response and immunological analyses after a single neoadjuvant dose can be used to predict clinical outcome and to dissect underlying mechanisms in checkpoint blockade.


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Procedimentos Cirúrgicos Dermatológicos , Melanoma/tratamento farmacológico , Neoplasias Cutâneas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos T CD8-Positivos , Quimioterapia Adjuvante , Feminino , Perfilação da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Terapia Neoadjuvante , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Neoplasias Cutâneas/patologia , Transcriptoma , Evasão Tumoral
17.
Gut ; 68(5): 905-915, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30622109

RESUMO

OBJECTIVE: A 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. DESIGN: By 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. RESULTS: HBV-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. CONCLUSIONS: Overall, 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.


Assuntos
Linfócitos T CD8-Positivos/fisiologia , Produtos do Gene pol/metabolismo , Vírus da Hepatite B/imunologia , Hepatite B Crônica/metabolismo , Proteínas do Core Viral/metabolismo , Carga Viral , Adulto , Idoso , Estudos de Coortes , Feminino , Hepatite B Crônica/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo
18.
Z Gastroenterol ; 57(1): 74-86, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30641606

RESUMO

The success of immune modulation by checkpoint blockade approaches is currently transforming oncology, with high and long-lasting tumor responses in patients with advanced disease across many cancer entities. Rooted in the reinvigoration of adaptive antitumor immune responses through disinhibition of negative feedback pathways, these approaches are particularly effective in patients with significant preexisting T cell responses in tumors with high neoantigen load. While promising data is starting to emerge from clinical trials in liver cancer patients, the underlying immunobiology remains poorly understood. In this review, we discuss the immunological mechanisms underlying the success of current checkpoint blockade therapies and the implications for hepatology including management of immune-related hepatitis. Checkpoint blockade therapy provides novel therapeutic options for difficult-to-treat liver cancers but also novel clinical challenges for hepatologists facing immune-related adverse events.


Assuntos
Imunoterapia , Neoplasias Hepáticas/terapia , Antígeno B7-H1 , Antígeno CTLA-4 , Gastroenterologia , Hepatite Autoimune , Humanos , Receptor de Morte Celular Programada 1
19.
Front Immunol ; 10: 3039, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32038613

RESUMO

Mass cytometry has become an important technique for the deep analysis of single cell protein expression required for precision systems immunology. The ability to profile more than 40 markers per cell is particularly relevant for the differentiation of cell types for which low parametric characterization has proven difficult, such as exhausted CD8+ T cells (TEX). TEX with limited effector function accumulate in many chronic infections and cancers and are subject to inhibitory signaling mediated by several immune checkpoints (e.g., PD-1). Of note, TEX represent considerable targets for immune-stimulatory therapies and are beginning to be recognized as a major correlate of successful checkpoint blockade approaches targeting the PD-1 pathway. TEX exhibit substantial functional, transcriptomic and epigenomic differences compared to canonical functional T cell subsets [such as naïve (TN), effector (TEFF) and memory T cells (TMEM)]. However, phenotypic distinction of TEX from TEFF and TMEM can often be challenging since many molecules expressed by TEX can also be expressed by effector and memory T cell populations. Moreover, significant heterogeneity of TEX has been described, such as subpopulations of exhausted T cells with progenitor-progeny relationships or populations with different degrees of exhaustion or homeostatic potential that may directly inform about disease progression. In addition, TEX subsets have essential clinical implications as they differentially respond to antiviral and checkpoint therapies. The precise assessment of TEX thus requires a high-parametric analysis that accounts for differences to canonical T cell populations as well as for TEX subset heterogeneity. In this review, we discuss how mass cytometry can be used to reveal the role of TEX subsets in humans by combining exhaustion-directed phenotyping with functional profiling. Mass cytometry analysis of human TEX populations is instrumental to gain a better understanding of TEX in chronic infections and cancer. It has important implications for immune monitoring in therapeutic settings aiming to boost T cell immunity, such as during cancer immunotherapy.


Assuntos
Citometria de Fluxo , Imunidade Celular , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Biomarcadores , Diferenciação Celular/imunologia , Suscetibilidade a Doenças/imunologia , Citometria de Fluxo/métodos , Humanos , Imunofenotipagem/métodos , Imunoterapia , Contagem de Linfócitos , Fenótipo , Análise de Célula Única , Subpopulações de Linfócitos T/citologia
20.
PLoS One ; 13(12): e0208225, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30507970

RESUMO

BACKGROUND & AIMS: Serum interferon-gamma-inducible protein-10 (IP-10) is elevated in cholestatic liver diseases and predicts response to antiviral therapy in patients with chronic hepatitis C virus (HCV) infection. Dipeptidylpeptidase 4 (DPPIV) cleaves active IP-10 into an inactive form, which inhibits recruitment of CXCR3+ T cells to the liver. In this study the link between IP-10 levels, DPPIV activity in serum and CXCR3+ T cells is analysed in cholestatic and non-cholestatic liver patients. METHODS: In serum DPPIV activity (by enzymatic assay), IP-10 (by ELISA) and bile acids (BA) (by enzymatic assay) were analysed in 229 naive HCV genotype (GT) 1 patients and in 16 patients with cholestatic liver disease. In a prospective follow-up (FU) cohort of 27 HCV GT 1 patients peripheral CD3+CXCR3+, CD4+CXCR3+ and CD8+CXCR3+ cells were measured by FACS. RESULTS: In 229 HCV patients serum IP-10 levels correlated positively to DPPIV serum activity. Higher IP-10 levels and DPPIV activity were detected in cholestatic and in cirrhotic HCV patients. Increased IP-10 serum levels were associated with therapeutic non-response to antiviral treatment with pegylated-interferon and ribavirin. In the HCV FU cohort elevated IP-10 serum levels and increased BA were associated with higher frequencies of peripheral CD3+CXCR3+, CD4+CXCR3+ and CD8+CXCR3+ T cells. Positive correlation between serum IP-10 levels and DPPIV activity was likewise validated in patients with cholestatic liver diseases. CONCLUSIONS: A strong correlation between elevated serum levels of IP-10 and DPPIV activity was seen in different cholestatic patient groups. Furthermore, in cholestatic HCV patients a functional link to increased numbers of peripheral CXCR3+ immune cells could be observed. The source of DPPIV release in cholestatic patients remains open.


Assuntos
Quimiocina CXCL10/sangue , Colestase/sangue , Dipeptidil Peptidase 4/sangue , Hepatite C/sangue , Receptores CXCR3/metabolismo , Linfócitos T/metabolismo , Ácidos e Sais Biliares/sangue , Complexo CD3/metabolismo , Antígenos CD4/metabolismo , Colestase/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Hepatite C/metabolismo , Humanos , Leucócitos Mononucleares/metabolismo , Masculino
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