共刺激分子4—1BB与类风湿性关节炎

共刺激分子4-1BB及其配体4-1BBL属于肿瘤坏死因子超家族成员,为、T细胞的活化、增殖提供第二信号,并可促进细胞因子的分泌。类风湿性关节炎（RA）是一种慢性系统性自身免疫性疾病,已证实T细胞功能的偏移及细胞因子表达异常在RA的免疫炎症损伤的发生发展过程中起着重要作用,而4-1BB作为RA发病机制中的关键性因素已成为目前研究的热点,通过干预4-1BB／4—1BBL信号途径对RA进行免疫治疗也已是当前的研究方向。     

类风湿关节炎T细胞亚群4-1BB的表达与其分泌TH1/TH2细胞因子的关系

目的探讨体外培养的类风湿关节炎(rheumatoid arthritis,RA)T淋巴细胞上共刺激分子4-1BB的表达,及与其分泌T_H1/T_H2细胞因子的关系。方法应用流式细胞术检测体外培养的30例RA患者和20例正常对照者T细胞活化前后4-1BB的表达,并且应用ELISA方法检测培养上清液中IFN-γ、IL-4水平。结果RA患者CD4~ T和CD8~ T细胞表达的4-1BB明显高于正常对照组(表达百分率分别为18.56%±4.08%和10.33%±2.13%;1.24%±0.12%和0.87%±0.09%,P<0.01),经抗CD3单抗体外刺激后CD4~ T和CD8~ T细胞表达的4-1BB均显著高于活化前(表达百分率为33.21%±4.29%和21.35%±8.12%,P<0.01)。RA患者CD4~ T/CD8~ T比值明显升高,而且与4- 1BB~ CD4~ T细胞数呈正相关关系(r=0.84,P<0.01),RA患者T淋巴细胞培养液上清中IFN-γ、IL-4均高于正常对照组(P<0.05),经抗CD3单抗体外刺激后上清液中IFN-γ及Ib-4均明显高于活化前,以IFN-γ升高最为显著(P<0.01)。而且抗CD3单抗刺激前后4-1BB~ CD4~ T细胞数与培养上清液中IFN-γ水平均呈正相关关系(r=0.721,r=0.487,P<0.05)。结论类风湿关节炎患者T细胞表达的4-1BB在类风湿关节炎的发生发展中具有重要意义,4-1BB可能通过对CD4~ T细胞活化,促使T_H1细胞因子分泌,参与关节炎症和免疫损伤。     

小鼠髓系树突状细胞4-1BB及4-1BBL表达调节

探讨小鼠髓系树突状细胞(bone marrow-derived dendritic cells,BMDC)共刺激分子4-1BB及其配体4-1BBL表达的变化。将促DC成熟活化因子CD40L-CHO、TNF-α、LPS和IFN-γ,免疫负性调节因子IL-10以及各成熟活化因子与IL-10联合加入BMDC中,观察BMDC上4-1BB及4-1BBL表达的变化。结果显示,加入成熟活化因子的各组BMDC上4-1BB及4-1BBL表达与对照组相比有显著上调(P<0.05)。而IL-10组与对照组相比两者的表达显著下调(P<0.05),且各成熟活化因子与IL-10联合应用与单用IL-10组相比,BMDC上4-1BB和4-1BBL表达上调,有显著性差异(P<0.05)。提示成熟活化因子不仅能上调BMDC上4-1BB和4-1BBL的表达并且能有效拮抗mIL-10对BMDC上4-1BB和4-1BBL表达的下调作用。     

4-1BB T-cell antigen binds to mature B cells and macrophages,and costimulates anti-μ-primed splenic B cells

4-1BB is expressed on activated murine T cells and may function as an accessory signaling molecule during T-cell activation. To identify putative 4-1BB ligands, a fusion protein consisting of the extracellular domain of 4-1BB fused to human placental alkaline phosphatase (4-1BB-AP) was constructed. Alkaline phosphatase activity could then be used as an indicator of the relative amount of bound 4-1BB. These studies indicated that 4-1BB-AP specifically bound to the surface of various mature B and macrophage cell lines. 4-1BB-AP bound at low levels to T cell lines (non-activated and anti-CD3-activated), pre-B-cell lines, and an immature macrophage cell line. 4-1BB-AP did not bind to a glial tumor cell line, HeLa cells, or COS cells. In addition, 4-1BB-AP bound at higher levels to F(ab′)₂ anti-μ-activated primary B cells compared to anti-CD3-activated primary T cells. Scatchard analysis indicated that the A20 B cell lymphoma expressed 3680 binding sites per cell with a K_d of 1.86 nM . Affinity cross-linking studies demonstrated that a major cell surface species of 120 kDa bound to 4-1BB-AP 4-1BB-AP also bound to a minor species of approximately 60 kDa. The addition of paraformaldehyde-fixed SF21 cells expressing recombinant 4-1BB synergized with F(ab′)₂ anti-μ in inducing splenic B cell proliferation suggesting that 4-1BB may function as a regulator of B cell growth.     

Moslecular and biological characterization of human 4-1BB and its ligands

4-1BB was originally described as a cDNA expressed by activated murine T cells and subsequently demonstrated to encode a member of the tumor necrosis factor receptor family of integral membrane proteins. Recently, we identified and cloned a murine ligand for 4-1BB (mu4-1BB-L) and demonstrated it to be a member of an emerging family of ligands with structural homology to tumor necrosis factor. To characterize further the role of 4-1BB in the immune response we undertook to clone the human homologue of 4-1BB-L. However, attempts to isolate a cDNA encoding the human 4-1BB-L by cross-hybridization with the murine cDNA were unsuccessful. Therefore we first utilized cross-species hybridization to isolate a cDNA encoding human 4-1BB (hu4-1BB). A fusion protein consisting of the extracellular portion of hu4-1BB coupled to the Fc region of human immunoglobulin G1 (hu4-1BB.Fc) was then used to identify and clone a gene for human 4-1BB-L from an activated CD4⁺ T cell clone using a direct expression cloning strategy. Human 4-1BB-L shows 36% amino acid identity with its murine counterpart and maps to chromosome 19p13.3. Scatchard analysis demonstrated high-affinity binding of hu4-1BB.Fc to either native or recombinant human 4-1BB-L. Both monoclonal antibody to hu4-1BB and cells transfected with hu4-1BB-L induced a strong proliferative response in mitogen co-stimulated primary T cells. In contrast, ligation of 4-1BB on T cell clones enhanced activation-induced cell death when triggered by engagement of the TCR/xsCD3 complex.     

抗人4-1BB功能性单克隆抗体的研制及生物学特性研究

研制鼠抗人4-1BB功能性单克隆抗体及其在T细胞活化、增殖及信号转导中的作用。以小鼠肾肿瘤细胞转染人4- 1BB基因的细胞株4-1BB/293T为免疫原.采用B淋巴细胞杂交瘤技术,获取分泌特异性4-1BB单抗的杂交瘤细胞株。以体内诱生法产生腹水,Protein G亲和层析法进行纯化,快速定性试纸法鉴定单抗的亚类,MTT法检测单抗对T细胞的刺激作用,流式法检测单抗对T细胞凋亡的影响。结果显示:成功获得1株持续分泌特异性抗人4-1BB单抗的细胞株(命名为5D5).属于IgG2b。该单抗能特异识别人4-1BB分子,介导有效的共刺激信号,体外促进T细胞的增殖,抑制活化诱导的T细胞凋亡。总之,成功获得1株功能性4-1BB单抗,具有重要的研究和潜在应用价值。     

Dispensable role for 4-1BB and 4-1BBL in development of vaccinia virus-specific CD8 T cells

CD8 T cells are strongly induced in response to certain strains of vaccinia virus (VACV) and the generation of this population is tightly regulated by two Tumor Necrosis Factor (TNF)/TNFR superfamily members, OX40 (CD134) and CD27. In this study, we examined the role of another member of the TNFR superfamily, 4-1BB (CD137, TNFRSF9), and its ligand (4-1BBL, CD137L, TNFSF9), that have been described to control the generation of memory CD8 T cell populations elicited by other viruses such as influenza. Expression of 4-1BB and 4-1BBL was observed in wild-type mice during the primary infection, but we found that both 4-1BB and 4-1BBL deficient mice generated normal numbers of VACV-specific effector CD8 T cells that produced IFN-γ and TNF. Additionally, CD8 T cells deficient in 4-1BB were able to expand and persist comparably to wild-type T cells in response to VACV infection. Furthermore, the knockout mice also showed no defect in development of VACV-specific CD8 memory T cell populations. Lastly, showing alternate control mechanisms were not active in the gene-deficient environments that masked any activity, blocking 4-1BB/4-1BBL interactions using neutralizing antibody also had no effect on the number of VACV-specific memory CD8 T cells induced. Thus, our data demonstrate that 4-1BB and 4-1BBL do not play a strong or dominant role in driving the generation of high frequencies of VACV-specific CD8 T cells.     

小鼠自身免疫性心肌炎发病过程中4-1BB/4-1BBL和IL-15的表达及意义

目的： 探讨在小鼠自身免疫性心肌炎发病过程中4-1BB/4-1BBL、IL-15的表达和变化,及其免疫学活性对心肌炎的影响。方法：将提纯的猪心肌肌球蛋白和完全弗氏佐剂等体积混合成乳浊液在1 d、8 d及30 d免疫具有遗传易感性的BALB/c小鼠,建立实验性自身免疫性心肌炎（EAM）模型。对照组小鼠仅用完全弗氏佐剂皮下注射。分别于初次免疫后21 d、80 d进行心肌炎症评分及血清肌钙蛋白I(cTnI)测定,免疫组化检测心肌淋巴细胞活化诱导受体配体（4-1BBL）的表达,ELISA法检测血清白细胞介素-15(IL-15)的浓度,RT-PCR技术检测4-1BB/4-1BBL和IL-15 mRNA在小鼠心肌组织中的表达。结果：在急性期21 d,EAM组小鼠心肌组织见不同程度的炎性细胞浸润和心肌细胞变性坏死、血清cTnI水平升高（P<0.05）;80 d EAM组小鼠心肌组织炎症减弱伴有纤维化出现、cTnI较前期降低;心肌4-1BBL和血清IL-15在EAM组中表达明显,在对照组中少量表达（P<0.05）;21 d EAM组小鼠心肌组织中4-1BB/4-1BBL和IL-15基因表达水平均高于对照组(P<0.01),且与心肌炎症呈明显的正相关,80 d时表达仍然升高(P<0.05)。结论：4-1BB/4-1BBL和IL-15在EAM小鼠发病过程中的表达上调,4-1BB/4-1BBL共刺激通路和IL-15可能协同参与了自身免疫性心肌炎的发生发展过程。     

4-1BB signaling beyond T cells

Originally discovered as a T cell-activating molecule, 4-1BB (CD137) is now also recognized as an activator of non-T cells, thus imparting a new dimension to its potential in vivo effects. 4-1BB expression is seen on a variety of non-T cells including activated dendritic cells (DCs), monocytes, neutrophils, B cells and natural killer (NK) cells, and promotes their individual effector functions. The T cell- and non-T cell-activating ability of 4-1BB may be the basis of its powerful anti-cancer, anti-autoimmune and anti-viral effects. Here we discuss the consequence and importance of 4-1BB signaling in non-T cells. We consider its effects on immune regulation, and the distinct and/or overlapping pathways involved in these responses, as well as possible therapeutic applications.     

4-1BB在人外周血γδT细胞活化中的协同刺激作用

采用结核杆菌(Mtb)低分子多肽刺激人外周血单个核细胞,流式细胞术(FCM)检测不同活化时相γδT细胞膜表面4-1BB分子的表达;用阻断型4-1BB配体(4-1BBL)单抗阻断4-1BB/4-1BBL信号,FCM检测γδT细胞的增殖比率和细胞内产生IFN-γ的情况,同时与阻断CD28/B7-1信号相比较。结果显示,静止的γδT细胞膜表面不表达4-1BB分子,Mtb抗原刺激后6 h,4-1BB即有明显表达(29.71%),48 h达到高峰(49.79%);与未阻断组相比,阻断4-1BB/4-1BBL信号,γδT细胞的增殖效应和细胞内IFN-γ的产生均明显下降(P<0.01),与CD28/B7-1信号阻断组相比,差异无显著性(P>0.05)。提示4-1BB/4-1BBL信号同CD28/B7-1信号一样,可为γδT细胞活化提供协同刺激作用。     

小鼠4-1 BB分子的配体识别主要区域定位及结构分析

目的 明确4-1 BB分子的配体结合4-1 BB分子胞外区的关键区域和基本结构.方法 分区表达鼠4-1 BB胞外区结构域及其天然配体,利用ELISA和Western blot等方法 对4-1 BB分子的配体识别结构域进行定位.结果 4-1 BB分子半胱氨酸寓集结构域(cysteine-rich domain,CRD)Ⅱ是配体结合的主要结构域,不结合CRD Ⅰ和CRDⅢ.免疫刺激性抗4-1 BB单克隆抗体2A,主要结合4-1 BB分子CRD与跨膜区之间的连接区(STP区),同时对包括CRDⅡ的各个CRDs有弱识别,可封阻4-1 BB与其配体结合.结论 4-1 BB分子配体的主要识别区位于4-1 BB分子胞外CRD Ⅱ,具有空间结构特点,此为进一步分析结合区及其关键氨基酸提供了资料.     

Lipopolysaccharide preferentially induces 4-1BB ligand expression on human monocyte-derived dendritic cells

Dendritic cells (DCs) represent a promising tool for immunotherapy. A key feature in their action is to provide co-stimulatory signals for full activation of T cells. In view of recent studies demonstrating the critical role of 4-1BB co-stimulation in T cell response, it is of importance to optimize 4-1BB ligand (4-1BBL) expression on human monocyte-derived DCs (MDDCs), the DC source of many clinical studies. In this study, two types of MDDCs, generated in granulocyte-macrophage colony-stimulating factor and interleukin-4 (GM-CSF/IL-4-DCs) or in interferon-β and IL-3 (IFN-β/IL-3-DCs), were analyzed for 4-1BBL expression in response to several known DC activators. Immature MDDCs expressed 4-1BBLs at very low levels. Lipopolysaccharide (LPS) was the only activator that preferentially triggered 4-1BBL expression on either MDDCs, but 4-1BBL-positive cells were significantly more frequently observed on LPS-activated GM-CSF/IL-4-DCs (30.2±2.6% versus 14.3±1.2%). Combinations of multiple activating signals did not bring about enhanced 4-1BBL stimulatory capacity. In addition, plasmid DNA transfection and necrotic cell pulsing of GM-CSF/IL-4-DCs for antigen loading also resulted in 4-1BBL up-regulation. However, in all circumstances, the induced 4-1BBL levels were low in comparison with CD80 co-stimulatory molecule. Finally, by demonstrating LPS-matured GM-CSF/IL-4-DCs from sorted 4-1BBL^high population augmented T cell expansion and survival, we propose that efforts are required to increase 4-1BBL levels on MDDCs achieved by current activation schemes.     

阻断4-1BB/4-1BBL通路在系统性红斑狼疮患者T淋巴细胞活化中的作用

目的 探讨协同刺激分子4-1BB/4-1BBL在系统性红斑狼疮(systemic lupus erythematosus,SLE)T淋巴细胞活化中的作用机制.方法 应用RT-PCR和Western blot方法检测体外培养20例SLE患者和20例正常对照者T淋巴细胞活化前后及应用抗4-1BB单抗阻断后p38 MAPK和NF-kB表达的变化.结果 SLE患者T淋巴细胞NF-kB mRNA和p38 MAPK mRNA表达及其蛋白水平明显高于正常对照组(P均＜0.01),活化后的表达进一步升高(P均＜0.01).阻断4-1BB/4-1BBL通路后SLE患者T淋巴细胞p38 MAPK mRNA及蛋白水平的表达均明显下降(P均＜0.01),但是NF-kB mRNA及蛋白水平的表达无明显变化(P＞0.05).结论 协同刺激分子4-1BB可能通过p38MAPK信号转导通路促使SLE患者T淋巴细胞的活化与增殖.     

4-1BB／4-1BBL在T细胞免疫应答及疾病发生中的作用

共刺激分子4-1BB和4-1BB配体（4-1BBL）属于肿瘤坏死因子／肿瘤坏死因子受体（TNF／TN—FR）超家族的重要成员,分别表达在活化的T细胞及树突状细胞（DC）上。4-1BB与4-1BBL相互作用产生的共刺激信号能够促进T细胞增殖、分化以及细胞因子的产生。4-1BB／4—1BBL信号途径在自身免疫性疾病、肿瘤、病毒感染等疾病的发生、发展过程中起着重要的免疫调节作用。干预调节4-1BB／4-1BBL信号途径有望为疾病的免疫治疗提供新的思路。     

4-1BB信号拮抗肿瘤细胞培养上清诱导的树突状细胞凋亡

为研究4-1BB信号拮抗肿瘤细胞培养上清诱导的树突状细胞(DC)凋亡的作用,采用rmGM-CSF联合rmIL-4诱导小鼠骨髓细胞分化为未成熟树突状细胞(imDC),分别经rmTNF-α、4-1BB激发型单克隆抗体(2A)或TNF-α联合2A激发DC成熟。未成熟或成熟DC分别与不同浓度的肿瘤培养上清混合培养。流式细胞仪测定DC表面CD80、CD86的表达,3H-TdR掺入法测定DC激发T细胞活化增殖能力;JAM法测定未成熟或成熟DC与肿瘤上清混合培养后DNA片断形成率。结果显示:经2A或TNF-α刺激后,DC激发T细胞活化的能力显著提高;5%、10%、20%、50%小鼠肿瘤细胞株A20或B16培养上清与未成熟DC共育24h后,DNA片断形成率分别为16%、29%、41%、51%和20%、27%、37%、58%,且该效应具有时间依赖性;DC经2A或TNF-α激发48h后,不同浓度肿瘤培养上清诱导DNA片断形成率显著降低。因此,肿瘤细胞可以通过分泌可溶性因子诱导未成熟DC凋亡;4-1BBmAb能促进DC的发育成熟,并能有效地抑制肿瘤细胞培养上清诱导的DC凋亡。     

Human 4-1BB regulates CD28 co-stimulation to promote Th1 cell responses

Our present study provides evidence that the 4-1BB signal is critical to CD28 co-stimulation in maintaining T cell activation when CD28 has been down-regulated because of repeated stimulation. The 4-1BB signal synergized with CD28 co-stimulation by lowering the threshold of anti-CD28 required to sustain proliferation and IL-2 production. The 4-1BB signal also modulated CD28-mediated cytokine profiles by markedly enhancing Th1 but suppressing Th2-type cytokine production. The 4-1BB signal generated Th1-type cells, as identified by intracellular IFN-γ production. IFN-γ induction was detected preferentially in 4-1BB-expressing cells, but not in those expressing CD30. 4-1BB and CD30 were induced in both CD4⁺ and CD8⁺ cells, but the location of the two molecules was mutually exclusive in each T cell subset. Our study suggests that the 4-1BB signal regulates CD28 co-stimulation in the targeted subset cells to favor Th1 development and maintain long-term cell growth.     

T-cell intrinsic effects of GITR and 4-1BB during viral infection and cancer immunotherapy

GITR [glucocorticoid inducible tumor necrosis factor receptor (TNFR)-related protein] and 4-1BB are costimulatory TNFR family members that are expressed on regulatory and effector T cells as well as on other cells of the immune system. Here we discuss the role of GITR and 4-1BB on T cells during viral infections and in cancer immunotherapy. Systemic treatment with agonistic anti-4-1BB antibody leads to a number of immune system abnormalities, and clinical trials of anti-4-1BB have been terminated. However, other modes of 4-1BB ligation may be less toxic. To date, similar toxicities have not been reported for anti-GITR treatment of mice, although anti-GITR antibodies can exacerbate mouse autoimmune models. Intrinsic effects of GITR and 4-1BB on effector T cells appear to predominate over their effects on other cell types in some models. Despite their similarities in enhancing T-cell survival, 4-1BB and GITR are clearly not redundant, and both pathways are required for maximal CD8(+) T-cell responses and mouse survival following severe respiratory influenza infection. GITR uses TNFR-associated factor (TRAF) 2 and TRAF5, whereas 4-1BB recruits TRAF1 and TRAF2 to mediate survival signaling in T cells. The differential use of signaling adapters combined with their differential expression may explain the non-redundant roles of GITR and 4-1BB in the immune system.     

激动型抗4-1BB抗体3H3交联促进CD8+T细胞中Akt激酶活性

目的:研究4-1BB信号促进CD8 T细胞增殖、存活及Akt活性的变化。方法:利用小鼠CD8α T细胞磁珠负性分选试剂盒制备高纯度CD8 T细胞,并通过体外抗CD3单克隆抗体(mAb)刺激活化CD8 T细胞。再通过流式细胞术(FCM)分析3H3交联与否,四唑盐(WST-1)/ECS检测CD8 T细胞的增殖程度,Annexin V检测抗凋亡能力,免疫印迹法分析胞内Akt磷酸化水平及Akt激酶活性。结果:3H3交联可以明显促进活化的CD8 T细胞增殖和存活,并且3H3介导的4-1BB信号可明显促进CD8 T细胞内Akt磷酸化水平及Akt激酶活性。结论:Akt途径可能参与了3H3交联介导的4-1BB信号对CD8 T细胞增殖与存活的调节效应。     

Characterization and application of three novel monoclonal antibodies against human 4-1BB: distinct epitopes of human 4-1BB on lung tumor cells and immune cells

4-1BB, a member of the tumor necrosis factor receptor (TNFR) superfamily, is a costimulatory receptor that is primarily expressed on activated T cells and professional antigen-presenting cells. In this study, the expression pattern of 4-1BB on immunology cells and tumor cells was explored by flow cytometry using newly generated three anti-4-1BB monoclonal antibodies (mAbs; 6F9, 7D6, and 1G11), which bind to distinct 4-1BB epitopes. Compared with the available 4-1BB mAb 4B4-1 that recognized 4-1BB on activated T cells and monocytes, the novel mAbs also could recognize 4-1BB on some cancer cell lines, particularly on lung cancer cell lines such as SPC-A-1, H446, H460, and H1299 by flow cytometry analysis, western blot, and RT-PCR. Immunohistochemistry staining showed the 4-1BB was expressed on lung tumor tissue (33/35) but not on normal lung tissue (3/3). It was determined that 4-1BB was strictly expressed on lung cancer cells, which may provide information on the 4-1BB signal in tumor immunology mechanism.