B、T淋巴细胞弱化因子在免疫性疾病中的研究进展

B、T淋巴细胞弱化因子(B and T lymphocyte attenuator, BTLA)是21世纪初发现的负向共刺激分子成员,是Ig超家族的Ⅰ型跨膜蛋白,其配体为肿瘤坏死因子超家族的疱疹病毒侵入介体(herpesvirus entry mediator, HVEM)。BTLA调节γδT细胞和固有淋巴细胞(ILC...     

共抑制分子BTLA在慢性HIV-1感染中的特点及与疾病进展的相关性研究

目的:观察慢性HIV-1感染者中CD4~+和CD8~+ T淋巴细胞上BTLA(B and T lymphocyte attenuator,CD272)分子的表达及临床意义.方法:采集34例慢性HIV-1感染者和15例健康人的外周血,分离外周血单个核细胞,用间接免疫荧光染色方法标记并用流式细胞术检测T淋巴细胞上BTLA表达的百分比及平均荧光强度,并将BTLA的表达水平与患者CD4~+ T淋巴细胞计数和病毒载量做相关性分析.结果:与健康对照相比,HIV-1慢性感染者中CD4~+和CD8~+ T细胞上的BTLA表达均明显下降,且BTLA的下降在各组HIV-1慢性感染者中也有明显差异,随着疾病进展,BTLA表达进行性下降.CD4~+ T细胞上BTLA表达比率与平均荧光强度均与CD4~+T淋巴细胞计数呈明显正相关,而与病毒载量呈负相关.结论:在慢性HIV-1感染中,随着疾病进展,BTLA的进行性下降可能是机体活化和抑制信号失衡、导致免疫系统广泛活化的重要因素,恢复BTLA抑制信号的强度可能是治疗HIV感染的新策略.     

B/T淋巴细胞间抑制信号研究进展

B7-CD28家族共刺激信号分子在T淋巴细胞激活、抑制机体耐受及产生理想的T细胞免疫应答等方面起着关键作用。B7-CD28家族共信号分子已经被集中的研究,并且引起免疫调控领域充分的重视。CD80/CD86/CD28/CTLA-4经典途径的新功能的发现以及这一家族包括B7-H1/B7-DC/PD-1,B7-H2/ICOS,B7-H4和BTLA的新途径的确定,都拓宽了我们对T细胞介导的免疫应答和免疫耐受调控的理解。本文就CTLA-4、PD-1和BTLA对T细胞应答的负性调节以及在维持外周耐受中起作用的研究进展作一综述。     

HIV 感染者调节性T 细胞表面B、T 淋巴细胞衰减因子的表达研究

目的:对HIV 感染者调节性T 细胞(Regulatory T cell,Treg)上B 、T 淋巴细胞衰减因子(B and T lymphocyte at-tenuator,BTLA)的表达水平进行检测,并探讨其在HIV 感染进程中的作用。方法:选取24 例感染在一年之内的HIV 早期感染者(Early HIV infected patients,EHI 组)、14 例感染超过一年的HIV 慢性感染者(CD4+ T 计数>200 cells/ μl,HIV 组)、6 例AIDS患者(CD4+ T 计数<200 cells/ μl,AIDS 组)和9 例健康人作为对照,应用流式细胞仪检测不同时期感染者及健康对照者Treg 细胞BTLA 的表达水平,分析其与疾病进展及免疫活化的相关性。结果:随着HIV 疾病进展,EHI 组、HIV 组及AIDS 组Treg 细胞BTLA 表达水平依次升高,其中HIV 组与AIDS 组Treg 细胞BTLA 表达水平显著高于EHI 组(P<0.05 及P<0.01),AIDS 组Treg 细胞BTLA 的表达水平高于健康对照(P<0.05);Treg 细胞BTLA 表达水平与CD4+ T 淋巴细胞计数呈负相关(P<0.001),与病毒载量呈正相关(P<0.01);Treg 细胞BTLA 表达水平与活化CD4+ CD38+ T 淋巴细胞及CD4+ HLA-DR+ T 淋巴细胞呈正相关(P<0.001,P<0.001)。结论:HIV 感染者Treg 细胞BTLA 表达升高,与疾病进展显著相关,提示其可能通过加强Treg 细胞的抑制功能加速疾病进展,并为未来HIV 感染的干预提供信息。     

B／T淋巴细胞问抑制信号研究进展

B7-CD28家族共刺激信号分子在T淋巴细胞激活、抑制机体耐受及产生理想的T细胞免疫应答等方面起着关键作用。B7-CD28家族共信号分子已经被集中的研究，并且引起免疫调控领域充分的重视。CD80/CD86，CD28/CTLA-4经典途径的新功能的发现以及这一家族包括B7-H1／B7-DC／PD-1，B7-H2／ICOS，B7-H4和BTLA的新途径的确定，都拓宽了我们对T细胞介导的免疫应答和免疫耐受调控的理解。本就CTLA-4、PD-1和BTLA对T细胞应答的负性调节以及在维持外周耐受中起作用的研究进展作一综述。     

基于B、T淋巴细胞衰减因子探讨膝骨关节炎患者肺功能变化的机制及相关性分析

目的 通过观察膝骨关节炎(knee osteoarthritis,KOA)患者肺功能参数、B、T淋巴细胞衰减因子(B and T lymphocyte attenuator,BTLA)及血清细胞因子的变化情况,探讨KOA患者肺功能变化的可能分子机制.方法 选取2011年10月-2012年7月安徽中医学院第一附属医院风湿病科收治的住院、门诊患者47例.应用肺功能仪检测患者肺功能指标；流式细胞术检测BTLA；ELISA法检测白介素(interleukin,IL)-1β、IL-10、基质金属蛋白酶9(matrix metalloproteinase-9,MMP-9)、基质金属蛋白酶组织抑制物-1(tissue inhibitor of matrix metalloprotease-1,TIMP-1)；魏氏法测定血沉(erythrocyte sedimentation rate,ESR)；日立7060型全自动生化分析仪进行测定超敏C反应蛋白(high-sensitivityC-reactive protein,hs-CRP).结果 (1)与正常组比较,KOA患者用力肺活量(forced vital capacity,FVC)、一秒用力呼气容积(forced expiratory volume in 1 second,FEV1)、FEV1/FVC、用力最大呼气流量(peak expiratory flow,PEF)、最大呼气中段流量(maximal mid-expiratory flow,MEF25-75)、用力呼气50％流量(Maximal mid-expiratory flow velocity in pulmonary vital capacity 50％,MEF50)、用力呼气25％流量(maximal mid-expiratory flow velocity in pulmonary vital capacity 25％,MEF25)、CD3+ BTLA+T细胞、CD4+BTLA+T细胞、IL-10、TIMP1明显降低,IL-1β、MMP9明显升高.(2)相关性分析显示,FVC与Lequesne MG、症状分级量化总分、病程、MMP9呈负相关,与CD3+ BTLA+T细胞、IL-10、TIMP1呈正相关；FEV1与CD3+ BTLA+T细胞、CD4+BTLA+T细胞、TIMP1呈正相关,与病程呈负相关；MEF50与CD3+ BTLA+T细胞、CD4+ BTLA+T细胞呈正相关.结论 KOA患者在发生关节软骨病变的同时,伴有肺功能的下降.其机制可能与BTLA表达水平下降,IL-1β、MMP9明显升高,IL-10、TIMP1明显降低,诱发异常免疫应答,从而介导气道损伤,导致KOA患者肺功能下降有关.     

B和T淋巴细胞衰减因子(BTLA)在类风湿关节炎滑膜组织的表达

目的:探讨CD28家族共抑制分子B和T淋巴细胞衰减因子在类风湿关节炎(RA)患者滑膜组织内的表达。方法:免疫组化法检测RA患者滑膜组织BTLA的表达;并使用免疫荧光法检测BTLA的细胞定位及分布。结果:免疫组化结果证实,RA患者滑膜组织中有大量的BTLA阳性细胞,形态观察提示这些阳性的细胞主要是淋巴结处的淋巴细胞及巨噬细胞;免疫荧光分析进一步表明这些BTLA+细胞主要为CD3+T细胞及CD68+巨噬细胞,少数CD31+内皮细胞也表达BTLA。此外,对比其他B7家族共刺激分子在滑膜组织中的分布,免疫荧光发现BTLA共表达于B7-H1+,B7-H4+及HVEM+细胞,但不表达于B7-DC+及B7-H3+细胞。结论:关节炎滑膜组织内有大量BTLA阳性细胞,提示BTLA有可能参与并调节了关节炎的病理进程。     

B/T细胞弱化分子-CD28超家族一个新的共抑制分子的研究进展

B／T细胞弱化分子（BTLA）是最近发现的CD28家族共抑制分子，主要表达于B细胞、T细胞和抗原递呈细胞表面。BTLA的配体是TNF超家族成员疱疹病毒进入介质（HVEM）。HVEM-BTLA信号途径对T、B细胞的活化起负调节作用，在调节机体免疫应答，维持自身免疫稳定中起着十分重要的作用。深入研究BTLA的生物学功能及其作用机制对探寻治疗肿瘤、自身免疫性疾病、移植排斥反应、变态反应性疾病等的新干预措施具有重要意义。     

BTLA-HVEM通路阻断对树突状细胞功能影响的体内外研究

目的 探讨阻断BTLA-HVEM(B/T淋巴细胞弱化因子疱疹病毒进入介质)通路对树突状细胞功能的影响和相关免疫学机制.方法 构建小鼠BTLA胞外功能区的真核表达载体psBTLA,转染CHO细胞;HSP70-TC-1肿瘤抗原肽刺激小鼠骨髓来源DCs,流式细胞仪检测处理后DCs表面BTLA、HVEM的表达,同时给予转染了psBTLA质粒的CHO细胞的培养上清处理后,检测DCs表面B7-1的表达,ELISA检测上清中IL-12的分泌;处理后的DCs刺激脾细胞,检测淋巴细胞增殖和细胞因子分泌;检测psBTLA体内转染对宫颈癌细胞系TC-1成瘤小鼠DCs表达B7-1和肿瘤生长的影响.结果 成功构建小鼠BTLA胞外段的真核表达载体psBTLA,获得了稳定转染psBTLA的CHO细胞,在其培养上清检测到BTLA胞外段(sBTLA)的表达.DCs经抗原肽刺激后BTLA、HVEM表达均上调,加入含sBTLA的上清处理后上调B7-1,上清中分泌的IL-12增加,与脾细胞共培养时促进细胞增殖和IL-2、IFN-γ的分泌;体内基因转染psBTLA促进DCs表达B7-1以及抑制肿瘤生长.结论 通过sBTLA阻断BTLA-HVEM共抑制通路,可以进一步促进DCs的功能,更好地激活淋巴细胞,促进抗肿瘤免疫应答.     

风湿病患者肺功能降低与BTLA阳性细胞及调节性T细胞的数量减少有关

目的探讨B、T淋巴细胞衰减因子(BTLA)、调节性T细胞(Treg)与风湿病患者肺功能降低的关系。方法选取482例风湿病患者,包括类风湿性关节炎(RA)198例,强直性脊柱炎(AS)114例、干燥综合征(SS)102例、骨关节炎(OA)68例,应用肺功能仪检测患者肺功能水平,采用流式细胞术检测患者外周血B、T淋巴细胞衰减因子(BTLA)和调节性T细胞(Treg)表达。结果与正常组比较,风湿病患者肺功能降低,外周血BTLA、Treg表达降低;与风湿病BTLA、Treg正常组比较,BTLA、Treg异常组肺功能参数第1秒用力呼气容积(FEV1)、最大呼气流量(PEF)、50%肺活量位的最大呼气流量(FEF50)、FEF75降低(P0.05或P0.01);相关分析显示,肺功能参数用力肺活量(FVC)、最大通气量(MVV)、FEV1、FEF25、FEF50分别与BTLA、Treg呈正相关,FVC、FEV1、FEF50、FEF75分别与IgA、IgM呈负相关(P0.05或P0.01)。结论风湿病患者肺功能降低可能与BTLA、Treg表达降低,促使T细胞、B细胞过度异常活化有关。     

BTLA: a new inhibitory receptor with a B7-like ligand

The B and T lymphocyte attenuator, BTLA, is a recently discovered Ig superfamily member. BTLA engagement results in downregulation of T-cell activation, and mice deficient in BTLA show increased incidence and severity of autoimmune disorders. A novel B7 family member, B7x (B7S1, B7-H4), has been proposed as the ligand for BTLA. A B7x-Ig fusion protein inhibits T-cell activation and interleukin-2 (IL-2) production. Thus, cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1) and BTLA comprise an expanding set of inhibitory receptors expressed on lymphocytes.     

B and T lymphocyte attenuator regulates T cell activation through interaction with herpesvirus entry mediator

B and T lymphocyte attenuator (BTLA) provides an inhibitory signal to B and T cells. Previously, indirect observations suggested that B7x was a ligand for BTLA. Here we show that BTLA does not bind B7x; instead, we identify herpesvirus entry mediator (HVEM) as the unique BTLA ligand. BTLA bound the most membrane-distal cysteine-rich domain of HVEM, distinct from regions where the ligands LIGHT and lymphotoxin-alpha bound HVEM. HVEM induced BTLA tyrosine phosphorylation and association of the tyrosine phosphatase SHP-2 and repressed antigen-driven T cell proliferation, providing an example of reverse signaling to a non-tumor necrosis factor family ligand. The conservation of the BTLA-HVEM interaction between mouse and human suggests that this system is an important pathway regulating lymphocyte activation and/or homeostasis in the immune response.     

BTLA/HVEM抑制信号通路研究进展

BTLA是新近发现的Ig家族的抑制性受体,其唯一配体HVEM,来自TNF受体超家族,可与TNF家族的LIGHT结合提供正向刺激信号.而BTLA与HVEM的相互作用传递抑制信号下调淋巴细胞的免疫应答.这两个来自不同家族的受体间的负向调节作用,改变了对传统抑制性信号通路作用方式的看法.通过介绍目前对其生物学特性、信号传导机制及与相关疾病关系的研究,为进一步深入了解免疫应答的调控机制及寻找治疗自身免疫病、移植排斥、肿瘤等疾病的新方法提供参考.     

BTLA, a new inhibitory B7 family receptor with a TNFR family ligand

B and T lymphocyte attenuator （BTLA）, identified as an immune inhibitory receptor recently, plays widespread roles on T and B cells. Emerging evidence has generated plentiful information on the mechanisms which BTLA mediates negative regulation in immune responses and involves in a variety of physiological and pathological processes. The exploration of the biological mechanisms and regulation of BTLA will open possibilities on novel therapeutic strategies in immune-related diseases. Cellular ＆ Molecular Immunology. 2005;2（6）：427-432.     

BTLA is a lymphocyte inhibitory receptor with similarities to CTLA-4 and PD-1

During activation, T cells express receptors for receiving positive and negative costimulatory signals. Here we identify the B and T lymphocyte attenuator (BTLA), an immunoglobulin domain-containing glycoprotein with two immunoreceptor tyrosine-based inhibitory motifs. BTLA is not expressed by naive T cells, but it is induced during activation and remains expressed on T helper type 1 (T(H)1) but not T(H)2 cells. Crosslinking BTLA with antigen receptors induces its tyrosine phosphorylation and association with the Src homology domain 2 (SH2)-containing protein tyrosine phosphatases SHP-1 and SHP-2, and attenuates production of interleukin 2 (IL-2). BTLA-deficient T cells show increased proliferation, and BTLA-deficient mice have increased specific antibody responses and enhanced sensitivity to experimental autoimmune encephalomyelitis. B7x, a peripheral homolog of B7, is a ligand of BTLA. Thus, BTLA is a third inhibitory receptor on T lymphocytes with similarities to cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and programmed death 1 (PD-1).     

Distinct expression and inhibitory function of B and T lymphocyte attenuator on human T cells

B and T lymphocyte attenuator (BTLA) has been recently identified as a new inhibitory receptor of the CD28 superfamily, with similarities to cytotoxic T lymphocyte activation antigen (CTLA)-4 and programmed death (PD)-1. Engagement of BTLA on T lymphocytes can profoundly reduce the T cell receptor (TCR)-mediated activation. In this study, we generated four monoclonal antibodies (mAbs) against human BTLA. Using the produced mAb 8H9, the BTLA molecule was found to distinctly express on many subgroups of immunocytes and show a regulatory expression, which was in accordance with its unique ligand herpes virus entry mediator (HVEM) in the process of T cell activation. In addition, the expression of BTLA was increased in the CD4(+) and CD8(+) T cells of pleural fluid in lung cancer patients. Furthermore, we showed that the BTLA-induced negative signals could be triggered by mAb 7D7. Cross-linking of BTLA with mAb 7D7 suppressed T lymphocyte proliferation, downregulated the expression of T cell activation marker CD25, and inhibited the production of interferon (IFN)-gamma, interleukin (IL)-2, IL-4, and IL-10.     

BTLA:一个新发现的CD28超家族共刺激分子

BTLA是新近发现的一个CD8超家族共刺激分子,它与CTLA-4、PD-1有相似的结构和功能,对T细胞活化起负性调控作用,同时还可作为胸腺细胞阳性选择的早期标志。研究发现BTLA可与HVEM直接结合,目前多认为HVEM是BTLA的配体。BTLA—HVEM相互作用沟通了CD28及TNFR两个共刺激分子超家族,是一个比较特别的．CD28超家族分子。     

LIGHT-HVEM—BTLA共信号分子的研究进展

BTLA是新近发现的一个CD28超家族共抑制分子,它的配体不是B7家族成员而是TNF受体超家族成员HVEM。HVEM同时还存在一个TNF超家族的配体,即T细胞上可诱导表达的与HSV的糖蛋白D竞争结合HVEM的淋巴毒素类似物（LIGHT）。HVEM可以作为一个分子开关,通过结合LIGHT或BTLA7E免疫调节中发挥不同的作用。     

CpG-ODN-induced sustained expression of BTLA mediating selective inhibition of human B cells

BTLA (B- and T-lymphocyte attenuator) is a prominent co-receptor that is structurally and functionally related to CTLA-4 and PD-1. In T cells, BTLA inhibits TCR-mediated activation. In B cells, roles and functions of BTLA are still poorly understood and have never been studied in the context of B cells activated by CpG via TLR9. In this study, we evaluated the expression of BTLA depending on activation and differentiation of human B cell subsets in peripheral blood and lymph nodes. Stimulation with CpG upregulated BTLA, but not its ligand: herpes virus entry mediator (HVEM), on B cells in vitro and sustained its expression in vivo in melanoma patients after vaccination. Upon ligation with HVEM, BTLA inhibited CpG-mediated B cell functions (proliferation, cytokine production, and upregulation of co-stimulatory molecules), which was reversed by blocking BTLA/HVEM interactions. Interestingly, chemokine secretion (IL-8 and MIP1β) was not affected by BTLA/HVEM ligation, suggesting that BTLA-mediated inhibition is selective for some but not all B cell functions. We conclude that BTLA is an important immune checkpoint for B cells, as similarly known for T cells.     

Allergen‐specific immunotherapy alters the expression of B and T lymphocyte attenuator,a co‐inhibitory molecule,in allergic rhinitis

Background B7/CD28 family co‐signalling molecules play a key role in regulating T cell activation and tolerance. Allergen‐specific immunotherapy (SIT) alters allergen‐specific T cell responses. However, the effect of SIT on the expression of various co‐signalling molecules has not been clarified. Objective We sought to determine whether SIT might affect the expression of three co‐inhibitory molecules, programmed death (PD)‐1, B7‐H1 and B and T lymphocyte attenuator (BTLA), in Japanese cedar pollinosis (JCP). Methods Peripheral blood mononuclear cells (PBMCs) were isolated from JCP patients who had or had not received SIT. PBMC were cultured in the presence or absence of Cry j 1, after which the cell surface expression of PD‐1, B7‐H1 and BTLA, as well as IL‐5 production, were determined. In addition, the effect of BTLA cross‐linking on IL‐5 production was examined. Results After Cry j 1 stimulation, no significant differences in PD‐1 and B7‐H1 expression were observed between SIT‐treated and SIT‐untreated patients. BTLA expression was down‐regulated in untreated patients after Cry j 1 stimulation and up‐regulated in SIT‐treated patients. Up‐regulation of BTLA in SIT‐treated patients was particularly apparent in a CD4⁺ T cell subset. IL‐5 production was clearly reduced among SIT‐treated patients, and the observed changes in BTLA expression correlated negatively with IL‐5 production. Moreover, immobilization of BTLA suppressed IL‐5 production in JCP patients. Conclusion These results suggest that both IL‐5 production and down‐regulation of BTLA in response to allergen are inhibited in SIT‐treated patients with JCP. BTLA‐mediated co‐inhibition of IL‐5 production may contribute to the regulation of allergen‐specific T cell responses in patients receiving immunotherapy.