循环IFN-γ的Vδ1+和Vδ2+γδT淋巴细胞无症状性持续性乙肝病

StephenW

Increased Frequencies of Circulating IFN-γ-Producing Vδ1+ and Vδ2+ γδ T Cells in Patients with Asymptomatic Persistent Hepatitis B Virus Infection

To cite this article:
Conroy Melissa J., Mac Nicholas Ross, Taylor Margaret, O'Dea Siobhan, Mulcahy Fiona, Norris Suzanne, and Doherty Derek G.. Viral Immunology. May 2015, 28(4): 201-208. doi:10.1089/vim.2014.0133.

Published in Volume: 28 Issue 4: May 7, 2015
Online Ahead of Print: March 19, 2015

  

Author information
Melissa J. Conroy,1,2,3 Ross Mac Nicholas,4 Margaret Taylor,4 Siobhan O'Dea,5 Fiona Mulcahy,5 Suzanne Norris,4 and Derek G. Doherty1,2
1Department of Immunology, School of Medicine, Trinity College, Dublin, Ireland.
2Department of Surgery, School of Medicine, Trinity College, Dublin, Ireland.
3Institute of Immunology, National University of Ireland, Maynooth, Co. Kildare, Ireland.
4Hepatology Centre, St. James's Hospital, Dublin, Ireland.
5Genitourinary and Infectious Diseases Clinic, St. James's Hospital, Dublin, Ireland.
Address correspondence to:
Dr. Derek G. Doherty
Department of Immunology, School of Medicine
Trinity College Dublin
St. James's Hospital
Dublin 8
Ireland
E-mail: [email protected]
ABSTRACT

Hepatitis B virus (HBV) is a leading cause of liver cirrhosis and hepatocellular carcinoma. The outcome of HBV infection is largely determined by the host immune response, with virus-specific cytotoxic T cells being able to mediate immunity against HBV as well as causing liver pathology. γδ T cells are reported to be depleted in patients with HBV-associated liver disease. However, it is not known if these cells control HBV infection in patients with asymptomatic chronic HBV infection. In this study, the frequencies, phenotypes, and interferon-γ production were examined by circulating γδ T cell subsets in a group of asymptomatic HBV carriers with low viral loads and little evidence of liver disease. It is shown that γδ T cells expressing Vδ1 and Vδ2 T cell receptors and effector-memory phenotypes are found at higher frequencies in these patients compared to controls. Vδ2 T cells from the patients expressed interferon-γ significantly more frequently than Vδ2 T cells from healthy donors in the absence of ex vivo stimulation. These data suggest that effector-memory IFN-γ-producing Vδ2 T cells may contribute to the control of HBV in patients with asymptomatic infection, without mediating liver pathology.

StephenW

循环IFN-γ的Vδ1+和Vδ2+γδT淋巴细胞无症状性持续性乙肝病毒感染的频率增加

举这篇文章：
康罗伊梅丽莎J.，苹果尼古拉斯·罗斯，泰勒玛格丽特，O'Dea的西沃恩，马尔卡希菲奥娜，诺里斯苏珊和多尔蒂德里克摹..病毒免疫。 2015年5月，28（4）：201-208。 DOI：10.1089 / vim.2014.0133。

发表在卷：28日发行4：2015年5月7日
网上先于印刷版：2015年3月19日

  

作者信息
梅丽莎J.康罗伊，1,2,3罗斯Mac的尼古拉斯，4玛格丽特·泰勒，4西沃恩O'Dea的，5菲奥娜马尔卡希，5苏珊·诺里斯，4和Derek G. Doherty1,2
免疫学教研室，医学院，圣三一学院，都柏林，爱尔兰。
教研室外科，医学，圣三一学院，都柏林，爱尔兰的学校。
爱尔兰，梅努斯，基尔代尔公司，爱尔兰国立大学3Institute免疫。
4Hepatology中心，圣詹姆斯医院，都柏林，爱尔兰。
5Genitourinary和传染病诊所，圣詹姆斯医院，都柏林，爱尔兰。
通讯地址：
德里克G.多尔蒂博士
免疫学系，医学院
都柏林三一学院
圣詹姆斯医院
都柏林8
爱尔兰
电子信箱：[email protected]
摘要

乙型肝炎病毒（HBV）是肝硬化和肝细胞癌的主要病因。 HBV感染的结果在很大程度上取决于宿主的免疫反应决定的，与病毒特异性细胞毒性T细胞能够介导抗HBV免疫以至造成肝脏病理。 γδT细胞中报告例HBV相关肝病被耗尽。但是，现在还不知道这些细胞是否控制HBV感染患者无症状慢性HBV感染。在这项研究中，频率，表型，和干扰素γ的产生是由循环γδT细胞亚群中的一组无症状HBV携带者具有低病毒负荷和肝脏疾病的迹象检查。它表明，γδT细胞表达Vδ1和Vδ2T细胞受体和效应记忆表型被发现在这些患者中更高的频率与对照比较。从患者Vδ2T细胞在缺乏离体刺激的表达从健康供体干扰素γ显著频率大于Vδ2T细胞。这些数据表明，效应记忆IFN-γ产生Vδ2T细胞可能有助于HBV患者无症状感染的控制，而不介导肝脏病理。

StephenW

Introduction

Hepatitis B virus (HBV) remains a major global health problem and is attributable to 780,000 deaths each year, despite the availability of a vaccine (58). More than 240 million people worldwide have chronic HBV infection, which can lead to cirrhosis, hepatocellular carcinoma (HCC), and liver failure (30,47). While the majority of adult HBV infections resolve, 80–90% of infected neonates develop chronic infection and 15–25% die from HBV-related liver disease or cancer (58). The majority of patients with chronic HBV infection do not develop liver disease and are said to be asymptomatic carriers. However, as many as 20% of patients in the immune control phase of chronic HBV infection develop reactivation of the virus and cirrhosis within 5 years (25,43,46). Therefore, although a vaccine exists with 95% efficacy, new treatments are urgently required to treat the vast numbers of HBV-infected patients worldwide who are at risk of HBV-related liver cirrhosis and cancer (58).

Resolution of HBV infection is associated with strong, polyclonal, and multi-specific CD8+ cytotoxic T-lymphocyte (CTL) responses directed against multiple viral epitopes, while chronic HBV infection is characterized by lower numbers and lower potency of HBV-specific CTLs (38,43,46,55). Inefficient T cell priming by dendritic cells (21,40), immunomodulation by regulatory T cells (28,54), and clonal exhaustion due to upregulation of inhibitory receptors, such as PD-1 (27,59), have been implicated as factors that contribute to the inadequate T cell responses. Moreover, CD8+ CTL-mediated cytotoxicity is strongly implicated in HBV-related liver damage but does not appear to play a major role in eliminating the virus, while IFN-γ produced by virus-specific CTLs and natural killer (NK) cells are thought to mediate clearance of HBV by interfering with viral replication and by recruiting other antigen-nonspecific effector cells (13,31,36,38,55). Therefore, the ideal immune response against HBV must control viral replication but limit hepatocyte cytotoxicity and immune-mediated liver damage.

Roles for γδ T cells in antiviral immune responses have been reported for cytomegalovirus (17,32), Epstein–Barr virus (18), human immunodeficiency virus (HIV) (45), and herpes simplex virus (39) infections. γδ T cells have also been implicated in immune responses to hepatitis C virus (HCV) and are thought to play a role in liver injury associated with the virus (41,56). Sing et al. (50) reported that γδ T cells were expanded in the blood of patients with HBV infection who seroconverted. Subsequently, Chen et al. (10,11) reported that Vδ2 T cells, the most abundant subset of γδ T cells in human blood and liver (37), are depleted in patients with chronic HBV infection and in patients who develop HBV-associated acute-on-chronic liver failure (HBV-ACLF). In contrast, Vδ1 T cells, the most abundant γδ T cell subset in the intestine, were expanded in the blood of patients with HBV-ACLF. γδ from HBV-ACLF patients exhibited enhanced cytotoxicity and inflammatory cytokine production compared to their counterparts in chronic HBV patients and healthy controls, suggesting that γδ T cells play a role in liver injury in HBV-ACLF (10).

In the present study, the potential role of γδ T cell subsets in immunity against HBV in the absence of liver injury was investigated by studying a cohort of patients with persistent HBV infection (HBsAg-positive) but low viral burden (<20,000 copies/mL) and no evidence of liver disease (alanine aminotransferase [ALT] <70 IU/mL). This patient cohort can be considered as having an efficient immune response against HBV, which is under sufficient regulatory control and does not cause significant pathology but fails to eliminate the virus completely (34). The frequencies, differentiation status, and IFN-γ production of the Vδ1+ and Vδ2+ subsets of γδ T cells were examined to assess, for the first time, their potential roles in controlled asymptomatic HBV infection.

StephenW

介绍

乙型肝炎病毒（HBV）仍然是一个主要的全球性健康问题，并且是由于每年780000例死亡，尽管疫苗（58）的可用性。 240多万人在全球有慢性HBV感染，可导致肝硬化，肝细胞癌（HCC）和肝功能衰竭（30,47）。虽然大多数的成人感染乙肝病毒解决，新生儿感染的80-90％发展成慢性感染和15-25％死于乙肝相关的肝脏疾病或癌症（58）。多数病人有慢性HBV感染不发展肝病被说成是无症状携带者。然而，多达20％的患者在慢性HBV感染的免疫控制阶段发展5年之内（25,43,46）的病毒和肝硬化激活。因此，尽管存在疫苗有95％的疗效，新的治疗方法，迫切需要治疗的全球HBV感染的病人谁是在HBV相关的肝硬化和癌症（58）风险的广大。

HBV感染的分辨率具有较强的，多克隆关联，和多特异性的CD8 +细胞毒性T淋巴细胞（CTL）应答针对多种病毒表位，而慢性HBV感染的特征在于较低的数字和的HBV特异性CTL的低级效力（38 43,46,55）。由树突细胞低效T细胞引发（21,40），免疫调节由调节性T细胞（28,54），和克隆用尽由于抑制性受体，例如PD-1（27,59）的上调，有牵连的因素该向T细胞应答不足。另外，CD8 + CTL介导的细胞毒作用，强烈牵连HBV相关的肝损伤，但没有出现在消除病毒中起主要作用，而IFN-γ通过病毒特异性CTL和自然杀伤产生（NK）细胞被认为通过与病毒复制的干扰，并通过招募其他抗原特异性效应细胞（13,31,36,38,55）介导的乙肝病毒清除。因此，对HBV理想的免疫反应必须控制病毒复制，但限制肝细胞的细胞毒性和免疫介导的肝损伤。

角色γδT细胞在抗病毒的免疫反应已报道了巨细胞病毒（17,32），Epstein-Barr病毒（18），人免疫缺陷病毒（HIV）（45），和单纯疱疹病毒（39）感染。 γδT细胞还已经涉及在免疫应答的丙型肝炎病毒（HCV）和被认为是发挥与病毒（41,56）相关的肝损伤的作用。唱歌等。 （50）报告说，γδT细胞在患者的HBV感染血清阳转谁的血液进行了扩充。接着，陈等人。 （10,11）报道，Vδ2T细胞，γδT细胞在人体血液和肝脏（37）的最丰富的子集，耗尽慢性HBV感染和谁开发乙肝相关急性发作，慢性肝病患者衰竭（HBV-ACLF）。与此相反，Vδ1T细胞，在肠道中最丰富的γδT细胞亚群，在患者的HBV-ACLF的血液进行了扩展。从HBV-ACLF患者γδ表现出增强细胞毒性和炎性细胞因子的产生相比，他们的同行在慢性乙型肝炎患者和健康对照，表明γδT细胞发挥作用的肝损伤的HBV-ACLF（10）。

在本研究中，γδT细胞亚群在免疫抗HBV在无肝损伤的潜在作用通过研究例持续HBV感染（HBsAg阳性），但低病毒负荷（<20,000份队列/ mL的调查），并没有任何证据肝病（丙氨酸氨基转移酶[ALT] <70 IU / mL）中。这个病人队列可以被看作是具有抗HBV的有效的免疫反应，这是在充分的监管控制和不会引起显著病理学，但无法完全消除病毒（34）。频率，分化状态，和IFN-γ生产的Vδ1+和Vδ2+亚群γδT细胞进行了检查，以评估，对于第一次，其在受控无症状HBV感染的潜在作用。

StephenW

Discussion

Vδ2 T cells are the predominant γδ T cell subset in human blood and are capable of producing IFN-γ and TNF-α (23,24), killing target cells (3,22,23), inducing activation and maturation of neutrophils (15,16), monocytes (24), B-cells (7,9), and dendritic cells (14,23,35), and presenting antigen to conventional CD4+ and CD8+ T cells (8). Their multifunctional capacity makes them ideal candidates for immunotherapy, and they are already the focus of several clinical trials (5,12,20,42,51). Vδ1 T cells are mainly found at mucosal surfaces and can exhibit immunostimulatory (26,29) and immunoregulatory (6) functions and are also under consideration as therapeutic targets (49).

Previous studies have revealed that Vδ2 T cell frequencies are decreased in the peripheral blood of chronic HBV patients with liver disease (11) and with HBV-ACLF (10), whereas Vδ1 T cells are expanded in the blood of HBV-ACLF patients and exhibit enhanced cytotoxicity and cytokine production compared to Vδ1 T cells from healthy controls. A cohort of asymptomatic, HBeAg-negative patients with persistent HBV infection with little evidence of liver disease was studied to provide an insight into the possible roles of γδ T cells in the immune control of HBV infection without significant liver injury. IFN-γ-producing Vδ1 and Vδ2 T cells with effector memory phenotypes are found at higher frequencies in the peripheral blood of these patients compared to controls. This suggests that these γδ T cell subsets are expanded in the circulation of patients, although the possibility that their increased frequencies are the result of a contraction of other T cell subsets cannot be excluded. Future studies are required to determine if Vδ1 and Vδ2 T cells are also expanded in the patients' livers. However, one study (44) has demonstrated that the numbers of peripheral and intrahepatic lymphocyte subtypes correlate closely with each other. Therefore, it is likely that effector memory Vδ1 and Vδ2 T cells may contribute to the immune control of HBV infection without causing liver pathology. The finding in the present study contrasts with the depletions of these cells in patients with HBV-associated liver disease and HBV-ACLF (10,11), which may facilitate liver damage. A role for Vδ2 T cells in immunity against HCV was reported by Agrati et al. (1), while the same group has provided evidence that Vδ1 T cells contribute to liver damage in patients with HCV infection (2).

As well as being expanded, the present study has revealed that greater proportions of Vδ1 and Vδ2 T cells from asymptomatic HBV patients displayed effector memory phenotypes compared to Vδ1 and Vδ2 T cells from uninfected control subjects, while the proportions of naïve Vδ1 and Vδ2 T cells were substantially lower. This suggests that Vδ1 and Vδ2 T cells are actively involved in immunity against HBV. Previous studies have shown that circulating HBV-specific CD8+ T cells from patients with acute HBV infection predominantly express memory T cell phenotypes, suggesting that they are also actively involved in immunity against HBV (52,57). It was also found that in the absence of ex vivo stimulation, the frequencies of IFN-γ-expressing Vδ2 T cells were higher in the HBV-infected patients compared to healthy controls. This suggests that Vδ2 T cells may control HBV infection and prevent immune-mediated damage by a mechanism that involves IFN-γ-mediated viral clearance. A similar role for subsets of NK cells in IFN-γ-mediated control of HBV without liver-damaging cytotoxicity has been proposed (13,48,60). The elevated frequencies of circulating Vδ1 T cells with effector memory phenotypes, although not as significant as those observed for Vδ2 T cells, suggest that these cells also play a role in the antiviral immune response against HBV, possibly via the production of IFN-γ and TNF-α (52). Since Vδ1 T cells have previously been implicated in the pathogenesis of HCV infection and arthritis, they might require strict regulation in asymptomatic HBV infection (2,4). However, they have also previously been shown to regulate inflammatory responses of CD8+ T cells in the small intestine via the suppression of IFN-γ, granzyme-B, and NKG2D expression (6). Further work is required to determine whether this γδ T cell subset plays a predominant antiviral or regulatory role in the control of HBV infection.

StephenW

讨论

Vδ2T细胞是人体血液中主要的γδT细胞子集，并且能够产生的IFN-γ和TNF-α（23,24），杀死靶细胞（3,22,23），诱导活化和嗜中性粒细胞的成熟（15 ，16），单核细胞（24），B细胞（7,9），和树突细胞（14,23,35），并呈递抗原至常规CD4 +和CD8 + T细胞（8）。其多功能的能力，使他们的理想人选免疫治疗，他们已经是几个临床试验（5,12,20,42,51）的焦点。 Vδ1T细胞主要存在于粘膜表面，并能表现出免疫（26,29）和免疫调节（6）功能，也正在考虑为治疗靶点（49）。

先前的研究已经表明，Vδ2T细胞的频率在慢性HBV肝病患者（11）的外周血被减少，并与HBV-ACLF（10），而Vδ1T细胞中HBV-ACLF患者和表现出的血液膨胀增强细胞毒性和细胞因子的产生与从健康对照Vδ1T细胞。无症状，HBeAg阴性患者的HBV持续感染与肝病的一点证据的队列研究提供洞察γδT细胞在HBV感染的免疫控制，而显著肝损伤的可能作用。 IFN-γ生产Vδ1和Vδ2T细胞的效应记忆表型被发现在这些患者的外周血与对照相比更高的频率。这表明，这些γδT细胞亚群中的患者的循环被扩展，虽然可能性，他们的频率增加是其它的T细胞亚群收缩的结果不能被排除。未来研究来确定是否Vδ1和Vδ2T细胞也扩大在患者的肝脏。然而，有一项研究（44）已经表明，外周和肝内淋巴细胞亚型的数目密切相关，与对方。因此，它很可能是效应记忆Vδ1和Vδ2T细胞可以在不引起肝脏病理有助于HBV感染的免疫控制。这一发现在本研究对比与这些细胞的患者的HBV相关肝病和HBV-ACLF（10,11）的枯竭，这可以促进肝损害。对于Vδ2T细胞在免疫抗HCV角色报道了Agrati和等。 （1），而在同一组提供的证据表明，Vδ1T细胞在HCV感染患者（2）向肝损伤。

以及正在扩大，目前的研究显示，从无症状乙肝患者Vδ1和Vδ2T细胞的比例越大显示相比，未感染对照组Vδ1和Vδ2T细胞效应记忆表型，而天真Vδ1和Vδ2T细胞的比例均大大降低。这表明，Vδ1和Vδ2T细胞积极参与免疫抗HBV。以前的研究已经表明，循环从急性HBV感染主要是明示记忆T细胞的表型HBV特异性CD8 + T细胞，这表明他们也在积极参与免疫抗HBV（52,57）。同时还发现，在没有离体刺激的IFN-γ表达Vδ2T细胞的频率分别在HBV感染的患者高于健康对照。这表明Vδ2T细胞可控制HBV感染和防止通过涉及IFN-γ介导的病毒清除的机制的免疫介导的损伤。对NK细胞的HBV的IFN-γ介导的控制没有肝脏损伤性的细胞毒性的子集类似的作用已被提出（13,48,60）。循环Vδ1T细胞与效应记忆表型的提高的频率，虽然不如那些观察Vδ2T细胞显著，表明这些细胞可以在抗HBV抗病毒免疫应答中发挥作用，通过产生IFN-γ可能与TNF-α（52）。因为Vδ1T细胞先前已经牵连在HCV感染和关节炎的发病机制，它们可能需要严格的监管无症状HBV感染（2,4）。然而，他们也先前已被证明在通过IFN-γ，粒酶B和NKG2D的表达（6）的抑制小肠调节CD8 + T细胞的炎症反应。进一步的工作是必需的，以确定这是否γδT细胞亚群起着HBV感染的控制的主要的抗病毒或调节作用。

总之，先前的研究已经提供了证据，未能清除HBV感染与Vδ2T细胞的枯竭相关联，并且降低了IFN-γ的表达，以在患者中观察到最高的病毒载量（11）的最大枯竭。在本研究的数据支持这一假设，与IFN-γ产生更高的频率，被发现在无症状的HBV患者低病毒载量的队列效应记忆Vδ2T细胞。这些调查结果牵连Vδ2T细胞作为主要参与者HBV复制的控制，最有可能通过产生IFN-γ。因为Vδ2T细胞已被确定为目标，免疫治疗，他们已经对几个临床试验（5,12,20,42,51）的焦点，所以建议，他们可能被用作基础以供将来免疫疗法来治疗乙肝患者持续感染症状。