Longitudinal liver sampling in patients with chronic hepatitis B starting antiviral therapy reveals hepatotoxic CD8+ T cells

Accumulation of activated immune cells results in nonspecific hepatocyte killing in chronic hepatitis B (CHB), leading to fibrosis and cirrhosis. This study aims to understand the underlying mechanisms in humans and to define whether these are driven by widespread activation or a subpopulation of immune cells. We enrolled CHB patients with active liver damage to receive antiviral therapy and performed longitudinal liver sampling using fine-needle aspiration to investigate mechanisms of CHB pathogenesis in the human liver. Single-cell sequencing of total liver cells revealed a distinct liver-resident, polyclonal CD8⁺ T cell population that was enriched at baseline and displayed a highly activated immune signature during liver damage. Cytokine combinations, identified by in silico prediction of ligand-receptor interaction, induced the activated phenotype in healthy liver CD8⁺ T cells, resulting in nonspecific Fas ligand–mediated killing of target cells. These results define a CD8⁺ T cell population in the human liver that can drive pathogenesis and a key pathway involved in their function in CHB patients.     

慢性乙型肝炎患者病程中CD5^＋B细胞及CD4／CD8的变化研究

目的研究CD5^＋B细胞和CIM／CD8在慢性乙型肝炎发病中的作用，以及他们之间的相关性。方法采用免疫荧光双标记技术和流式细胞仪对48例慢性乙型肝炎患者发病前后周围血中CIM／CD8比例和CD5^＋B细胞的百分率和37例健康对照者进行比较。结果在慢性乙型肝炎患者发病高峰期周围血CIM／CD8比例显著低于病情恢复期，且和健康对照组比较差异有显著性；而CD5^＋B细胞在慢性乙型肝炎患者发病高峰期，显著高于健康对照组和慢性乙型肝炎患者恢复期，差异有显著性。结论慢性乙型肝炎的发病和T细胞免疫功能的紊乱相关，而CD5^＋B可能在乙型肝炎的慢性化机制中发挥作用。     

Positive selection determines T cell receptor V beta 14 gene usage by CD8+ T cells

We report here a mAb, 14-2, reactive with TCRs that include V beta 14. The frequency of V beta 14+ T cells varies with CD4 and CD8 subset and is controlled by the H-2 genes. Thus CD8+ T cells from H-2b mice include approximately 2.3% V beta 14+ T cells while CD8+ T cells from mice expressing K kappa include greater than 8% V beta 14+ T cells. In all strains examined, 7-8% of CD4+ T cells express V beta 14. The frequent usage of V beta 14 in CD8+ T cells of K kappa-expressing mice is a result of preferential positive selection of V beta 14+ CD8+ T cells as demonstrated by analysis of radiation chimeras. These studies demonstrate that H-2-dependent positive selection occurs in unmanipulated mice. Furthermore, the results imply that positive selection, and possibly H-2 restriction, can be strongly influenced by a V beta domain, with some independence from the beta-junctional sequence and alpha chain.     

慢性乙型肝炎患者外周血CD8+CD25+FoxP3+调节性T细胞比例的变化及临床意义

目的 探讨外周血CD8+CD25+FoxP3+调节性T细胞(Treg)比例在慢性乙型肝炎(CHB)患者中的变化及临床意义.方法 选取2018年3-11月在滨海县第二人民医院传染科诊治的无症状乙型肝炎病毒(HBV)携带者28例为携带组,CHB患者28例为CHB组.同时选取28例年龄、性别匹配的健康体检者作为对照组.采用流...     

Independent association of T cell receptor beta and gamma chains with CD3 in the same cell

We have demonstrated that the PEER cell line, which expresses a CD3-associated TCR gamma chain on the cell surface, synthesizes TCR beta chain intracellularly. A percentage of this TCR beta chain associates with the CD3 complex intracellularly. These results indicate that TCR beta and gamma chains can be synthesized by one cell line, and that these chains can independently associate with the CD3 complex. However, the results argue against the formation of TCR beta gamma chain complexes in this cell line.     

甘草酸二铵对慢性乙型肝炎患者外周血CD4＋CD25＋Foxp3＋调节性T细胞的影响

目的探讨应用甘草酸二铵后,慢性乙型肝炎（CHB）患者外周血CD4＋CD25＋Foxp3＋调节性T细胞（Treg）的变化情况。方法选取CHB患者60例（CHB组）,甘草酸二铵治疗30d并采集治疗开始前、开始后15d、治疗结束后第2天的外周血,同时选择60例乙肝表面抗原阴性的健康体检者作为对照组。采用三色荧光标记流式细胞术检测两组外周血中CD4^＋CD25^＋Foxp3^＋Treg的含量。结果CHB组在治疗开始前外周血Treg高于对照组（P〈0．05）;治疗15d后,外周血Treg含量较治疗开始前下降,但仍高于对照组（P均〈0．05）;治疗30d后Treg含量进一步下降,与前两次相比,差异均具有统计学意义,且仍高于对照组（P均〈0．05）。结论外周血Treg可能参与CHB患者乙型肝炎病毒（HBV）免疫耐受。甘草酸二铵可降低患者外周血Treg数量,提示其可能通过对HBV的免疫调节实现其治疗作用。     

Development of CD4+CD8+ thymocytes in RAG-deficient mice through a T cell receptor beta chain-independent pathway

Antigen-binding diversity is generated by site-specific V(D)J recombination of the T cell receptor (TCR) and immunoglobulin loci in lymphocyte precursors. Coordinate expression of two structurally distinct recombinase activating genes, RAG-1 and RAG-2, is necessary for activation of site-specific V(D)J recombination. In mice bearing targeted disruptions of either the RAG-1 or RAG-2 genes, T and B lymphocyte development is arrested at the CD4-8- double negative (DN) thymocyte or B220+/CD43+ pro-B cell stage. Development of CD4+CD8+ double positive (DP) thymocytes is restored by expression of a functionally rearranged TCR beta transgene, suggesting that TCR beta expression is critical for this developmental transition. We have found that treatment of adult or newborn RAG-deficient mice with a single sublethal dose of gamma-irradiation rescues the DN to DP transition in early thymocytes, and this is accompanied by a dramatic increase in thymus cellularity. In contrast to the observed induction of thymocyte maturation, there was no phenotypic or functional evidence of coincident B lymphocyte development in irradiated RAG-deficient mice. Interestingly, maturation of DP thymocytes occurred without expression of TCR beta protein in the cytoplasm or on the cell surface. These results suggest an in vivo pathway for DP thymocyte development which is TCR beta chain independent.     

Regulatory CD4+CD25+ T cells restrict memory CD8+ T cell responses

CD4+ T cell help is important for the generation of CD8+ T cell responses. We used depleting anti-CD4 mAb to analyze the role of CD4+ T cells for memory CD8+ T cell responses after secondary infection of mice with the intracellular bacterium Listeria monocytogenes, or after boost immunization by specific peptide or DNA vaccination. Surprisingly, anti-CD4 mAb treatment during secondary CD8+ T cell responses markedly enlarged the population size of antigen-specific CD8+ T cells. After boost immunization with peptide or DNA, this effect was particularly profound, and antigen-specific CD8+ T cell populations were enlarged at least 10-fold. In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells. In depletion and transfer experiments, the suppressive function could be ascribed to CD4+CD25+ T cells. Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions. Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response. Down-modulation of CD8+ T cell responses during infection could prevent harmful consequences after eradication of the pathogen.     

Functional skewing of the global CD8 T cell population in chronic hepatitis B virus infection

The inflamed liver in chronic hepatitis B virus (HBV) infection (CHB) is characterized by a large influx of non–virus-specific CD8 T cells. Little is known about the functional capacity of these lymphocytes, which could provide insights into mechanisms of failure of viral control and liver damage in this setting. We compared the effector function of total circulating and intrahepatic CD8 T cells in CHB patients and healthy donors. We demonstrated that CD8 T cells from CHB patients, regardless of their antigen specificity, were impaired in their ability to produce interleukin-2 and proliferate upon TCR-dependent stimulation. In contrast, these CD8 T cells had preserved production of the proinflammatory cytokines interferon-γ and tumor necrosis factor-α. This aberrant functional profile was partially attributable to down-regulation of the proximal T cell receptor signaling molecule CD3ζ, and could be corrected in vitro by transfection of CD3ζ or replenishment of the amino acid arginine required for its expression. We provide evidence for depletion of arginine in the inflamed hepatic microenvironment as a potential mechanism for these defects in global CD8 T cell signaling and function. These data imply that polarized CD8 T cells within the HBV-infected liver may impede proliferative antiviral effector function, while contributing to the proinflammatory cytokine environment.     

Reactivity of V beta 17a+ CD8+ T cell hybrids. Analysis using a new CD8+ T cell fusion partner

Tolerance to IE molecules leads to deletion of V beta 17a-bearing T cells. Both, the CD4+ as well as the CD8+ T cell subsets are affected. A large percentage of CD4+ V beta 17a+ T cell hybrids recognize IE molecules. We now have investigated the reactivity for IE antigens of CD8+ V beta 17a+ T cell hybrids. Using a transfection approach, we have introduced the murine CD8 molecule into different V beta 17a+ T cell hybrids. Furthermore, the CD8 cDNA was transfected into the BW5147 alpha-beta- fusion partner. This allowed us to generate a large number of V beta 17a+ T cell hybrids by fusion with the appropriate T cells. Only 6% of T cell hybrids were stimulated to produce IL-2 upon incubation with IE+ cells. However, in those, the CD8 molecule seemed not to contribute to the IE reactivity of the hybrid, since mAbs against the CD8 molecule failed to inhibit their reactivity. This low percentage of V beta 17a+ CD8+ IE-reactive T cell hybrids contrasts with the strong reduction of CD8+ V beta 17a+ T cells in IE+ mice, strongly suggesting that elimination of such cells in the thymus occurs when they are coexpressing CD4 and CD8. This view was confirmed by the occasional expression of CD4 in some hybrids in which case IE reactivity was detected. Furthermore, we demonstrated the functional integrity of the introduced CD8 molecule by: (a) reconstitution of the IL-2 response in a class I-restricted TNP-specific T cell hybrid; and (b) by generation of alloreactive class I-restricted T cell hybrids using the new CD8+ fusion cell line. This CD8+ fusion partner, BWLyt2-4, should prove useful to study antigen processing and antigen presentation requirements of class I-restricted T cells.     

慢性乙型肝炎外周血T淋巴细胞亚群CD4+/CD25+和CD8+/CD28-的研究

目的 通过对慢性乙型肝炎患者外周血中CD4+/CD25+和CD8+/CD28-调节性淋巴细胞的分析,探讨其与慢性乙型肝炎患者临床状态的关系.方法 采用流式细胞技术多色荧光分析法,对280例慢性乙型肝炎患者、28例慢性病毒携带者以及22例健康体检者外周血中CD4+/CD25+和CD8+/CD28-淋巴细胞测定.结果 慢性病毒携带者外周血中CD4+/CD25+调节性淋巴细胞为(3.23±1.37)%,明显高于慢性乙型肝炎患者(1.85±1.38)%和正常健康对照(1.59±0.54)%(P＜0.05),但慢性乙型肝炎患者与正常健康对照差别无统计学意义(P＞0.05);而且HBeAg阴性慢性乙型肝炎(1.66±1.09)%与HBeAg阳性慢性乙型肝炎(1.96±1.43)%比较,差别无统计学意义(P＞0.05).慢性乙型肝炎患者和慢性病毒携带者外周血中CD8+CD28-调节性淋巴细胞分别为(79.53±16.07)和89.30±5.12)%,均明显高于正常健康对照(63.93±7.85)%(P＜0.05);另外,HBeAg阳性慢性乙型肝炎组(87.47±17.82)%,也明显高于HBeAg阴性慢性乙型肝炎组(64.90±15.26)%(P＜0.05).结论 慢性病毒携带者处于病毒携带状态可能与体内调节性淋巴胞CD4+/CD25+和CD8+/CD28-的升高有关.     

慢性乙肝患者外周血CD4+细胞HLA-DR、CD8+细胞CD28表达的检测及其意义

目的 检测乙肝患者外周血CD4^＋淋巴细胞表面HLA-DR和CD8^＋淋巴细胞表面CD28的表达情况,评价乙肝患者的细胞免疫状态。方法 荧光抗体CD4-PECY5、HLA-DR-FITC和CD8-PE、CD28-FITC标记淋巴细胞,流式细胞仪分别测定患者CD4^＋淋巴细胞表面HLA-DR和CD8^＋淋巴细胞表面CD28表达的百分率,并与HBV-DNA结果比较。结果 ①与正常对照组比较,乙肝患者组外周血CD4^＋淋巴细胞表面HLA-DR的表达显著升高（P〈0.001）,CD8^＋淋巴细胞表面CD28的表达显著降低（P〈0.01）;②乙肝患者DNA阳性（〉4000拷贝/ml）与阴性（〈4000拷贝/ml）组CD4^＋淋巴细胞表面HLA-DR和CD8^＋淋巴细胞表面CD28的表达比较均无显著性差异（P〉0.1）。结论 乙肝患者外周血CD4^＋细胞的免疫活化增强,CD8^＋细胞与抗原递呈细胞结合的作用减弱;淋巴细胞的活化情况与病毒复制情况及含量多少无关。     

CD4+CD25+ T cells regulate virus-specific primary and memory CD8+ T cell responses

Naturally occurring CD4+CD25+ regulatory T cells appear important to prevent activation of autoreactive T cells. This article demonstrates that the magnitude of a CD8+ T cell-mediated immune response to an acute viral infection is also subject to control by CD4+CD25+ T regulatory cells (Treg). Accordingly, if natural Treg were depleted with specific anti-CD25 antibody before infection with HSV, the resultant CD8+ T cell response to the immunodominant peptide SSIEFARL was significantly enhanced. This was shown by several in vitro measures of CD8+ T cell reactivity and by assays that directly determine CD8+ T cell function, such as proliferation and cytotoxicity in vivo. The enhanced responsiveness in CD25-depleted animals was between three- and fourfold with the effect evident both in the acute and memory phases of the immune response. Surprisingly, HSV infection resulted in enhanced Treg function with such cells able to suppress CD8+ T cell responses to both viral and unrelated antigens. Our results are discussed both in term of how viral infection might temporarily diminish immunity to other infectious agents and their application to vaccines. Thus, controlling suppressor effects at the time of vaccination could result in more effective immunity.     

Long-lasting CD8 T cell memory in the absence of CD4 T cells or B cells

The cellular basis of immunological memory has been a debated issue. It is not clear whether CD8 T cell memory is maintained by long-lived cells or by specific or nonspecific restimulation. Here, we have approached the question from a different angle, asking whether the cellular interactions that are required to maintain memory are the same as those necessary to activate cytotoxic T lymphocytes. We studied the CD8 memory response to the male antigen H-Y in mice deficient in CD4 cells, or B cells and found that memory in these mice was virtually unimpaired. These results suggest that CD8 memory is CD4 independent and that there is no requirement for long term retention of immune complexes on follicular dendritic cells, nor for B cells as antigen- presenting cells.     

Regions of the T cell receptor alpha and beta chains that are responsible for interactions with CD3

The T cell antigen receptor consists of the Ti alpha/beta heterodimer which recognizes antigen, and the associated CD3 chains, thought to be involved in signal transduction. To understand the nature of the interaction between Ti and CD3, chimeric molecules which included the COOH-terminal segments of Ti alpha or beta linked to the extracellular segment of CD8, were transfected into a mutant T cell deficient in Ti beta chain expression and cell surface CD3. Both chimeric chains were required to express the chimeric Ti and to restore CD3 surface expression. CD8/Ti and CD3 cointernalized and coimmunoprecipitated. Stimulation of the chimeric receptor induced transmembrane signaling events and cell activation. These results demonstrate that the Ti alpha and beta COOH termini containing the transmembrane domains are sufficient for structural and functional coupling of Ti to CD3.     

阿德福韦酯对慢性乙型肝炎患者CD4~+ CD25~+调节性T细胞表达水平的影响

目的:观察阿德福韦酯对慢性乙型肝炎(慢乙肝)患者血清CD4+CD25+调节性T细胞(CD4+CD25+regulatory T cells,CD4+CD25+Treg)表达水平的影响,揭示CD4+CD25+Treg在慢乙肝患者免疫发病机制中的作用,及阿德福韦酯治疗对机体的免疫调节机制的临床价值。方法:采用流式细胞术对66例慢乙肝患者(HBeAg阳性慢乙肝患者36例,HBeAg阴性慢乙肝患者30例)阿德福韦酯治疗前和治疗12、24、36及48周外周血CD4+CD25+Treg进行检测。同时采用实时荧光聚合酶链反应(PCR)检测相应时间点的血清HBVDNA。结果:外周血清CD4+CD25+Treg治疗前为(4.05±2.39)%,明显高于正常对照组的(2.26±1.42)%(P<0.01);治疗后CD4+CD25+Treg为(2.38±1.75)%,明显低于治疗前(P<0.01),与正常对照组相当(P>0.05)。CD4+CD25+Treg水平与病毒定量呈正相关。结论:阿德福韦酯抗病毒治疗后能使病毒载量下降,导致CD4+CD25+Treg下降,使免疫功能恢复。     

Essential roles of CD8+CD122+ regulatory T cells in the maintenance of T cell homeostasis

Regulation of immune system is of paramount importance to prevent immune attacks against self-components. Mice deficient in the interleukin (IL)-2/IL-15 receptor beta chain, CD122, are model animals of such immune attacks and characteristically have a high number of abnormally activated T cells. Here, we show that the transfer of CD8+CD122+ cells into CD122-deficient neonates totally prevented the development of abnormal T cells. Furthermore, recombination activating gene-2-/- mice that received wild-type mice-derived CD8+CD122- cells died within 10 wk after cell transfer, indicating that normal CD8+CD122- cells become dangerously activated T cells in the absence of CD8+CD122+ T cells. CD8+CD122+ cells could control activated CD8+ or CD4+ T cells both in vivo and in vitro. Our results indicate that the CD8+CD122+ population includes naturally occurring CD8+ regulatory T cells that control potentially dangerous T cells.