Nondeletional T-cell receptor transgenic mice: model for the CD4(+) T-cell repertoire in chronic hepatitis B virus infection

Chronicity after infection with the hepatitis B virus (HBV) can occur for a variety of reasons. However, once established, chronicity may be maintained by high levels of viral proteins circulating in the serum. To examine the characteristics of T cells capable of coexisting with the secreted hepatitis B e antigen (HBeAg), T-cell receptor (TCR) transgenic (Tg) mice were produced. To ensure that HBeAg-specific T cells would not be deleted in the presence of serum HBeAg, the TCR alpha- and beta-chain genes used to produce the TCR-Tg mice were derived from T-cell hybridomas produced from immunizing HBeAg-Tg mice. A TCR-Tg lineage (11/4-12) was produced that possessed a high frequency ( approximately 67%) of CD4(+) T cells that expressed a Tg TCR specific for the HBeAg. As predicted, when 11/4-12 TCR-Tg mice were bred with HBeAg-Tg mice no deletion of the HBeAg-specific CD4(+) T cells occurred in the thymus or the spleen. Functional analysis of the TCR-Tg T cells revealed that the HBeAg-specific CD4(+) T cells escaped deletion in the thymus and periphery by virtue of low avidity. Regardless of their low avidity, HBeAg-specific TCR-Tg T cells could be activated by exogenous HBeAg, as measured by cytokine production in vitro and T-helper-cell function for anti-HBe antibody production in vitro and in vivo. Furthermore, activated TCR-Tg HBeAg-specific T cells polarized to the Th1 subset were able to elicit liver injury when transferred into HBeAg or HBcAg-Tg recipients. Therefore, HBeAg-specific CD4(+) T cells that can survive deletion or anergy in the presence of circulating HBeAg nonetheless are capable of being activated and of mediating liver injury in vivo. The 11/4-12 TCR-Tg lineage may serve as a monoclonal model for the HBe/HBcAg-specific CD4(+) T-cell repertoire present in chronically infected HBV patients.     

Characterization of hepatitis B virus (HBV)-specific T-cell dysfunction in chronic HBV infection

Dysfunctional CD8+ T cells present in chronic virus infections can express programmed death 1 (PD-1) molecules, and the inhibition of the engagement of PD-1 with its ligand (PD-L1) has been reported to enhance the antiviral function of these T cells. We took advantage of the wide fluctuations in levels of viremia which are typical of chronic hepatitis B virus (HBV) infection to comprehensively analyze the impact of prolonged exposure to different virus quantities on virus-specific T-cell dysfunction and on its reversibility through the blocking of the PD-1/PD-L1 pathway. We confirm that chronic HBV infection has a profound effect on the HBV-specific T-cell repertoire. Despite the use of a comprehensive panel of peptides covering all HBV proteins, HBV-specific T cells were rarely observed directly ex vivo in samples from patients with chronic infection, in contrast to those from patients with acute HBV infection. In chronic HBV infection, virus-specific T cells were detected mainly in patients with lower levels of viremia. These HBV-specific CD8+ T cells expressed PD-1, and their function was improved by the blocking of PD-1/PD-L1 engagement. Thus, a broad spectrum of anti-HBV immunity is expressed by patients with chronic HBV infection and this spectrum is proportional to HBV replication levels and can be improved by blocking the PD-1/PD-L1 pathway. This information may be useful for the design of immunotherapeutic strategies to complement and optimize available antiviral therapies.     

Cellular immune response to hepatitis B virus-encoded antigens in acute and chronic hepatitis B virus infection

The proliferative response of PBMC to hepatitis B virus (HBV) envelope, core, and e Ag was analyzed prospectively in 21 patients with acute self-limited HBV infection and compared with the response of patients with chronic HBV infection and different levels of HBV replication (i.e., hepatitis e Ag (HBeAg)- or anti-HBe-positive) and liver damage (i.e., chronic active hepatitis or chronic asymptomatic carriers). Our results indicate that: 1) HBV-infected subjects who develop a self-limited acute hepatitis show a vigorous PBMC response to hepatitis B core Ag and HBeAg, as expression of T cell activation; 2) appearance of a detectable lymphocyte response to HBV nucleocapsid Ag is temporally associated with the clearance of HBV envelope Ag; 3) in patients with chronic HBV infection the level of T cell responsiveness to hepatitis B core Ag and to HBeAg is significantly lower than that observed during acute infection; 4) T cell sensitization to HBV envelope Ag in acute and chronic HBV infection is usually undetectable and when measurable is expressed transiently and at low levels. These results may reflect immune events of pathogenetic relevance with respect to evolution of disease and viral clearance.     

Comparison and significance of specific and non-specific cellular immunity in patients with chronic hepatitis B caused by infection with genotypes B or C of hepatitis B virus

The present study was designed to investigate possible relationships between the genotypes of hepa-titis B virus (HBV) and the HBV-specific cytotoxic T lymphocyte (CTL) responses. HBV genotypes, HBV specific CTL HBV DNA and other markers of HBV infection were determined in 138 patients with chronic hepatitis B. The results showed that the patients infected with genotype C (n=62) had a significantly lower HBV-specific CTL response than those who were infected with HBV genotype B (P<0.01). HBV DNA titer was higher in patients infected with HBV genotype C than in those infected with HBV geno-type B (P<0.01). Both alanine aminotransferase (ALT) and total bilirubin (TBIL) were higher in HBV genotype C infected patients than in those infected with genotype B (P<0.01 and <0.05, respectively). These results suggest that compared with CHB patients infected with HBV genotype B, the higher HBV DNA level and more severe liver damages in the patients infected with genotype C of HBV may be as-sociated with genotype C of the virus.     

Peripheral T-cell subsets in chronic type B hepatitis: correlation with biochemical and histological activities and hepatitis B e antigen/antibody status

Peripheral T-cell subsets in 77 patients with hepatitis B surface antigen (HBsAg)-positive chronic liver diseases were studied by indirect immunofluorescence using murine monoclonal antibodies against all peripheral T cells (OKT3), T-helper/inducer cells (OKT4), and T-cytoxic/suppressor cells (OKT8). OKT4/OKT8 ratios were significantly reduced in patients with hepatitis B e antigen (HBeAg)-positive chronic liver diseases, including 28 patients with chronic active hepatitis (CAH) (P less than 0.001) and 15 with chronic persistent hepatitis (CPH) (P less than 0.001). OKT4/OKT8 ratios were significantly lower in 21 HBeAg-negative patients with CAH (P less than 0.05), as compared to those of 17 normal controls, while T-cell subsets in 13 patients with HBeAg-negative CPH were essentially normal. Low OKT4/OKT8 ratios significantly correlated with HBeAg positivity (P less than 0.001) and CAH (P less than 0.05), as assessed with multiple regression. There was a significant negative correlation between OKT4/OKT8 ratios and serum glutamic-pyruvic transaminase (SGPT) levels (r = -0.37; P less than 0.01). It was concluded that in chronic hepatitis B virus infection, low OKT4/OKT8 ratios are closely related to active viral replication and more severe histological and biochemical activity.     

白介素-32在HBV感染者的变化及其临床意义

目的:探讨乙型肝炎病毒(HBV)感染者血清中白介素-32(IL-32)水平的变化及其临床意义。方法:对100例HBV感染者和30例健康者检测外周血清白细胞介素-32(IL-32)的含量,比较IL-32水平变化的规律,并分析其与临床疾病谱和HBV复制水平的关系。结果:(1)急性乙型肝炎、中度慢性乙型肝炎、重度慢性乙型肝炎患者血清IL-32水平与对照组有显著性差异(P<0.001);轻度慢性乙型肝炎患者血清IL-32水平高于健康对照组,但无统计学意义(P>0.05);急性乙型肝炎、中、重度慢性乙型肝炎患者血清IL-32水平均显著高于轻度慢性乙型肝炎组,且有统计学意义(P<0.001);急性乙型肝炎、重度慢性乙型肝炎患者血清IL-32水平均高于中度慢性乙型肝炎组,有统计学意义(P<0.001);急性乙型肝炎、重度慢性乙型肝炎组之间无明显差异(P>0.05)。(2)HBV感染者HBV-DNA阳性组IL-32水平较阴性组为高,但无差异;高、中、低病毒载量组之间血清IL-32水平也无差异(P>0.05)。(3)慢性乙型肝炎患者不同ALT水平组血清IL-32水平均高于对照组(P<0.05);且低、中、高ALT水平组之间与I...     

Hepatitis B viral factors and clinical outcomes of chronic hepatitis B

Hepatitis B virus (HBV) infection is an important health problem and the major cause of chronic hepatitis, cirrhosis as well as hepatocellular carcinoma (HCC) worldwide. The natural history of chronic HBV infection can be divided into 4 dynamic phases in HBV carriers who acquire the virus early in life. In general, the frequency and severity of hepatitis flares in the immune clearance or reactivation phase predict disease progression in HBV carriers, and early HBeAg seroconversion typically confers a favorable outcome. In contrast, late or absent HBeAg seroconversion after multiple hepatitis flares accelerates the progression of chronic hepatitis to cirrhosis. Recently, several hepatitis B viral factors predictive of clinical outcomes have been identified. For example, serum HBV DNA level at enrollment is the best predictor of adverse outcomes (cirrhosis, HCC and death from liver disease) in adults with chronic HBV infection. In addition, HBV genotype C, basal core promoter (BCP) mutant and pre-S deletion mutant are associated with increased risk of HCC development. In conclusion, hepatitis B viral factors such as serum HBV DNA level, genotype and mutants have already been clarified to influence disease progression of chronic hepatitis B. Further studies are needed to investigate the pathogenic mechanism of each viral factor.     

慢性乙型肝炎治疗的适应症和治疗方案的最新进展

目前,对于治疗一些慢性乙型肝炎病毒(HBV)感染边缘病例的最佳方法尚存在争议.血清HBV DNA和转氨酶水平、炎性坏死的程度和肝硬变程度决定着治疗的方案.所有转氨酶升高(＞正常上限值2倍)和血清HBVDNA＞20000 IU/mL的患者都需进行治疗.肝脏活检对于制定转氨酶轻度升高和血清HBV DNA＜20000 IU/mL的病例的治疗决策非常重要.慢性HBV患者如未接受治疗则需长期随访.现有7种药物获批用于治疗慢性乙型肝炎:普通和聚乙二醇IFNα、拉米夫定、阿德福韦、恩替卡韦、替比夫定和替诺福韦.应用聚乙二醇IFNα 1年疗程后持续治疗后效应使HbeAg阳性慢性乙型肝炎患者缓解率为30%-32%.口服抗病毒药物适用于大部分患者,并被用于长期治疗.然而,病毒耐药是长期口服抗病毒药物的主要缺点.     

Strain-specific T-cell suppression and protective immunity in patients with chronic hepatitis C virus infection

Hepatitis C virus (HCV) frequently persists with an apparently ineffective antiviral T-cell response. We hypothesized that some patients may be exposed to multiple HCV subtypes and that strain-specific T cells could contribute to the viral dynamics in this setting. To test this hypothesis, CD4 T-cell responses to three genotype 1a-derived HCV antigens and HCV antibody serotype were examined in chronically HCV infected (genotypes 1a, 1b, 2, 3, and 4) and spontaneously HCV recovered subjects. Consistent with multiple HCV exposure, 63% of patients infected with genotypes 2 to 4 (genotypes 2-4) and 36% of those infected with genotype 1b displayed CD4 T-cell responses to 1a-derived HCV antigens, while 29% of genotype 2-4-infected patients showed serotype responses to genotype 1. Detection of 1a-specific T cells in patients without active 1a infection suggested prior self-limited 1a infection with T-cell-mediated protection from 1a but not from non-1a viruses. Remarkably, CD4 T-cell responses to 1a-derived HCV antigens were weakest in patients with homologous 1a infection and greater in non-1a-infected patients: proportions of patients responding were 19% (1a), 36% (1b), and 63% (2-4) (P = 0.0006). Increased 1a-specific CD4 T-cell responsiveness in non-1a-infected patients was not due to increased immunogenicity or cross-reactivity of non-1a viruses but directly related to sequence divergence. We conclude that the T-cell response to the circulating virus is either suppressed or not induced in a strain-specific manner in chronically HCV infected patients and that, despite their ability to clear one HCV strain, patients may be reinfected with a heterologous strain that can then persist. These findings provide new insights into host-virus interactions in HCV infection that have implications for vaccine development.     

T-cell exhaustion in the tumor microenvironment

T-cell exhaustion was originally identified during chronic infection in mice, and was subsequently observed in humans with cancer. The exhausted T cells in the tumor microenvironment show overexpressed inhibitory receptors, decreased effector cytokine production and cytolytic activity, leading to the failure of cancer elimination. Restoring exhausted T cells represents an inspiring strategy for cancer treatment, which has yielded promising results and become a significant breakthrough in the cancer immunotherapy. In this review, we overview the updated understanding on the exhausted T cells in cancer and their potential regulatory mechanisms and discuss current therapeutic interventions targeting exhausted T cells in clinical trials.     

慢性乙型肝炎病毒感染自然史中HBsAg和HBsAb共存血清学模式分析

目的分析慢性乙肝病毒感染者HBsAg和HBsAb共存模式中血清学指标、HBV-DNA和肝酶等指标与自然病程的关系,探讨其临床意义。方法回顾性分析2016年重庆医科大学附属第一医院HBsAg和HBsAb双阳性患者的血清学指标、HBV-DNA和ALT、GGT检测结果,并对其感染的自然病程进行分析。结果 2016年该院HBsAg和HBsAb双阳性患者共520例,占全部HBV感染者的2.80%,占总送检标本数的0.42%。可分期的184例双阳性患者中,免疫耐受期47例(25.54%),免疫清除期17例(9.24%),低复制期108例(58.70%),再活动期12例(6.52%),HBsAg、HBsAg/HBsAb比值、HBV-DNA、ALT和GGT水平差异均有统计学意义(P<0.05),低复制期患者HBsAg/HBsAb比值均低于其他患者(P<0.05)。不同分期患者HBsAb、年龄和性别比较差异无统计学意义(P>0.05),且HBsAb水平均较低。284例资料完整HBsAg和HBsAb共存病例中HBV-DNA阳性136例,占47.89%。HBsAg浓度与HBV-DNA载量成正相关(r=0.295,P<0.05),HBsAb浓度与HBV-DNA载量之间没有显著相关性(r=0.04,P>0.05)。结论 HBsAg和HBsAb共存患者并不少见,与性别无关,可发生在各个年龄阶段,以低复制期患者为最多。HBsAg和HBsAb共存患者中HBsAb多以低浓度形式存在,且浓度与自然病程无关。HBsAb的出现并非代表患者体内病毒复制停止,在诊断及治疗HBsAg和HBsAb共存模式的乙肝病毒感染者时仍需结合HBV-DNA载量来判断感染状态。     

Control of virus-specific CD8+ T-cell exhaustion and immune-mediated pathology by E3 ubiquitin ligase Cbl-b during chronic viral infection

A characteristic feature in the immune response to many persistent viral infections is the dysfunction or deletion of antigen-specific T cells (exhaustion). This down-regulation of virus-specific T-cell response represents a critical control mechanism that exists within T-cell activation pathways to prevent lethal disease by inappropriate responses against disseminating virus infections. However, the molecular mechanisms by which the immune system determines whether to mount a full response to such infections remain largely unexplored. Here, we have established that in the murine lymphocytic choriomeningitis virus (LCMV) model, induction of the T-cell receptor signaling inhibitor molecule E3 ligase Cbl-b is critically involved in this decision. In particular, our data revealed that Cbl-b controls the program responsible for T-cell tolerance (exhaustion) induction during a chronic viral infection. Thus, Cbl-b(-/-) mice infected with a low dose of LCMV Docile mount a strong CD8(+) T-cell response that rapidly clears the infection, and the animals remain healthy; in contrast, down-regulation of the epitope-specific CD8(+) T-cell population in persistently infected Cbl-b(-/-) mice, compared to that in chronically infected B6 mice, was significantly delayed, and this was associated with increased morbidity and eventual death in nearly 20% of the animals. Interestingly, infection of Cbl-b(-/-) mice with a moderate virus dose resulted in rapid death with 100% mortality by 7 to 8 days after infection, caused by a dysregulated antiviral T-cell response, whereas the infected B6 mice survived and remained healthy. In conclusion, our results suggest that Cbl-b is critically involved in T-cell exhaustion and prevention of lethal disease.     

Prevalence of hepatitis B virus in chronic hepatitis B patients

The aim of the current study was to detect HBV by Real time - PCR in chronic hepatitis B patients. Fifty-eight sera of chronic hepatitis B patients were subjected during the period March 2009 to April 2010 in Ilam cities in West of Iran. Sera assayed by real-time PCR and ELISA methods. Twenty serum samples from healthy volunteers and non-hepatitis B patients and negative for hepatitis B seromarkers served as negative controls for the study. Among fifty-eight sera, ELISA showed fifty-five (94.8%) of the samples were positive for HBsAg and three (5.2%) negative results obtained while real-time PCR specified fifty-eight (100%) positive results in chronic hepatitis B patients. HBsAg status did not necessarily reflect HBV DNA level in the serum, as 5.2% of chronic Hepatitis B patients were positive for HBV DNA but negative for HBsAg. HBV DNA was not found to be positive amongst any of the negative controls. Real time - PCR is a sensitive and reproducible assay for HBV DNA quantization.     

恩替卡韦治疗45例慢性乙型重型病毒性肝炎的疗效观察

目的:评价恩替卡韦治疗慢性乙型重型病毒性肝炎的临床疗效。方法:45例患者在常规治疗的基础上给予恩替卡韦0.5mg,每日1次口服;另47例给予拉米夫定100mg,每日1次口服,存活患者的治疗时间不少于6个月。结果:恩替卡韦组临床疗效总有效率为80.0%,显著高于拉米夫定组总有效率66.0%(P<0.05);总胆红素(TBIL)和谷丙转氨酶(ALT)分别由治疗前的378.2±36.3umol/L和546.8±56.5 U/L降至146.5±35.4μmol/L和46.5±21.5U/L,凝血酶原活动度(PTA)由治疗前的32.5±5.8%升至59.5±16.8%,均较拉米夫定组改善明显(P<0.05);恩替卡韦组的HBeAg和HBV-DNA转阴率分别为71.4和66.7%,明显高于拉米夫定组的47.6%和45.2%(P<0.05)。病死率分别为6.7%和10.6%,无显著性差异(P>0.05)。结论:恩替卡韦治疗慢性乙型重型肝炎患者在临床疗效、肝功能改善和抑制病毒复制方面均优于拉米夫定治疗者。     

Interleukin IL-1B gene polymorphism in Tunisian patients with chronic hepatitis B infection: Association with replication levels

Approaches based on association studies have proven useful in identifying genetic predictors for many diseases, including susceptibility to chronic hepatitis B. In this study we were interested by the IL-1B genetic variants that have been involved in the immune response and we analyzed their role in the susceptibility to develop chronic hepatitis B in the Tunisian population. IL - 1B is a potent proinflammatory cytokine that plays an important role in inflammation of the liver. Polymorphic gene IL-1 ( − 511, +3954) was analyzed in a total of 476 individuals: 236 patients with chronic hepatitis B from different cities of Tunisia recruited in Pasteur Institute between January 2017 and December 2018 and 240 controls. Genomic DNA was obtained using the standard salting-out method and genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism. For − 511C>T polymorphism a significant association was found between patients and controls when comparing the genotypic (P = 0.007; χ² = 9.74 and odds ratio [OR] = 0.60; confidence interval [CI] = 0.41–0.89) and allelic (P = 0.001; χ² = 10.60) frequencies. When the viral load was taken into account a highly significant difference was found (P = 9 × 10⁻⁴; χ² = 10.89). For +3954C>T polymorphism a significant association was found between patients and controls when comparing genotypic (P = 0.0058; χ² = 7.60 and OR = 1.67; CI = 1.14–2.46) and allelic (P = 0.0029; χ² = 8.81) frequencies. T allele can be used as a strong marker for hepatitis B virus disease for both polymorphisms.     

HBsAg定量检测在慢性乙型肝炎自然病程中的意义

目的 研究慢性乙型肝炎病毒(HBV)感染自然病程中HBsAg水平变化情况以及和HBV DNA的关系.方法 将183名HBV感染者按感染的不同阶段分为免疫耐受期(IT)42例,免疫清除期(IC)46例,非/低水平复制期(LR)57例,和再活动期(HBeAg阴性肝炎组ENH)38例,回顾性分析每个阶段血清中HBsAg和HBV DNA水平以及两者之间的关系.结果 HBsAg含量分别为IT期最高[(3.81±0.46) Ig IU/mL],其次为IC期[(3.41±0.77) Ig IU/mL],最低是LR期[(2.87±0.61)Ig0.61IU/mL],每期之间HBsAg含量差异有统计学意义(P＜0.05),ENH组HBsAg含量又有所升高[(3.31 ±0.78)Ig IU/mL].IT期HBsAg与HBV DNA无相关(r=0.231,P＞0.05),IC期HBsAg与HBV DNA呈正相关(r=0.612,P＜0.05),ENH期两者无相关(r=0.189,P＞0.05);不同时期HBsAg含量与ALT均无相关性.结论 HBV感染的不同阶段HBsAg水平有差异,IT期最高,进入IC期后开始下降,在LR期降至最低,ENH期再度升高,HBsAg与HBV DNA仅在IC期有相关性,血清HBsAg的表达与不同的免疫背景有关.     

Cytokine expression during chronic versus occult hepatitis B virus infection in HIV co-infected individuals

Chronic hepatitis B virus infection is characterized by persistent detectable levels of hepatitis B surface antigen (HBsAg) and HBV DNA in the serum. In contrast, HBsAg is not detectable during occult HBV infection, despite the presence of HBV DNA. An altered host immune response could play a role in the development of occult HBV infection; however, potential differences in immune responses among chronic and occult HBV-infected patients have not been evaluated in vivo. In the current study, we evaluated serum levels of regulatory, apoptotic, and fibrotic/anti-fibrotic cytokines/markers as indicators of immune responses in 25 chronic and 12 occult HBV-infected patients. More than half of the patients in both chronic and occult HBV infection groups had IL-2, IL-4, IL-13, and IFN-γ levels below detectable limits. In contrast, most patients had detectable levels of IL-8, IL-10, IP-10, sFas, sFasL, and TGF-β1. Of these, only sFas was significantly different between the two groups, with lower levels observed during occult compared to chronic HBV infection (p = 0.01). As a surrogate marker of apoptotic inhibition, decreased sFas during occult HBV infection suggests that apoptosis occurs at different rates in occult compared to chronic HBV infection and therefore, may contribute to persistence of occult HBV infection.