4-1BB/4-1BBL在树突状细胞上的表达及其生物学意义

41BB/41BB配体（41BBL）属于肿瘤坏死因子受体/肿瘤坏死因子超家属成员,是机体特异性免疫应答中一对重要的共刺激分子，41BB/41BBL相互作用产生的共刺激信号在维持T细胞的增殖、活化及功能介导中发挥了重要作用。最新研究发现,41BB/41BBL共表达于树突状细胞（dendritic cells , DC），通过激发41BB/41BBL为DC活化提供了新的思路，进而增强DC激发T细胞的能力。因此，调节41BB/41BBL信号在以DC为主介导的肿瘤免疫中具有广阔的应用前景。     

鼻咽癌患者外周血共刺激分子的表达水平及其临床意义

目的:检测鼻咽癌患者外周血中T细胞表面程序性死亡分子1 (programmed death-1,PD-1)、刺激分子4-1BB的表达水平,探讨其在鼻咽癌中的临床意义.方法:选取2016年10至11月福建省肿瘤医院病理确诊的鼻咽癌患者30例作为研究对象,并选取同期本院体检中心性别、年龄相近的健康体检者30例作为对照组.通过流式细胞术检测外周血T细胞表面PD-1、4-1BB的表达情况以及T淋巴细胞亚群的比例.核磁共振扫描测量原发肿瘤体积.结果:鼻咽癌Ⅲ期患者外周血CD8+T细胞比例明显低于Ⅳ期患者[(13.1±6.2)％ vs(18.7±5.5)％,P＜0.05].与对照组相比,CD4+T细胞上PD-1阳性表达率显著上调[(8.7±6.5)％vs(3.87±3.0)％,P＜0.05].鼻咽癌患者外周血T细胞PD-1、4-1BB分子表达水平与临床分期、肿瘤负荷、性别及年龄无显著相关(P＞0.05).结论:鼻咽癌患者外周血PD-1和4-1BB两种共刺激分子在患者体内肿瘤免疫逃逸中可能存在协同效应.联合干预这两种共刺激分子的信号通路可能具有更高效持久的抗肿瘤效应,可为鼻咽癌免疫治疗提供新的思路.     

树突状细胞表达的共刺激分子与Th细胞分化

树突状细胞（dendritic　cell，DC）是体内功能最强的专职抗原提呈细胞，具有很强的抗原提呈能力，并能有效激发T细胞应答。DC在免疫学及肿瘤学乃至其他各学科中的作用日益受到重视，DC表面表达的共刺激分子及其生物学意义已成为研究的热点。共刺激分子的作用不仅限于对T细胞的激发、赋予T细胞活化的第二信号，并且参与Th细胞的极化。OX40／OX40L和ICOS／ICOSL信号介导Th2细胞分化；ICAM—1／LFA-1以及人4—1　BB／4-1BBL信号介导Th1细胞分化；CD40／CD40L信号在Th1／Th2型免疫应答中均发挥重要作用；PD-L1／PD-1可能与Th1细胞极化有关，而人PD-L2／PD-1共刺激信号下调Th1应答；人B7-H3信号参与Th1型免疫反应，鼠B7-H3信号负向调控Th1细胞分化；B7-1分子选择性的促进Thl反应，而B7-2分子参与调节Th2反应。深入探讨DC表达的共刺激分子与Th细胞分化的关系，调整Th1或Th2优势应答类型，可能为肿瘤等疾病的治疗提供新的思路。     

BTLA在肿瘤免疫中的作用及其临床意义

继程序死亡分子（PD-1）与细胞毒性T细胞相关抗原-4（CTLA-4）之后,CD28家族的新成员B、T淋巴细胞弱化因子（BTLA）已成为新的研究热点。BTLA表达谱介于PD-1和CTLA-4之间,它不仅表达于T细胞,在B细胞、NK细胞、巨噬细胞和树突状细胞中也有表达。BTLA与其配体结合传递共抑制信号,在机体抗肿瘤免疫应答中发挥负性调节作用,并与肿瘤的免疫逃逸机制相关,可能成为肿瘤生物治疗潜在的靶点。     

程序性凋亡分子1及其配体信号通道对调节性T淋巴细胞及肿瘤细胞的影响

程序性凋亡分子-1(PD-1)及其配体(PD-L1)是抑制性共同刺激分子中的重要成员之一,在多种肿瘤细胞及其相关细胞表面高表达,而肿瘤浸润的T淋巴细胞中调节性T淋巴细胞(Treg)的比例也异常升高.PD-L1与PD-1结合和Treg帮助肿瘤逃避免疫清除减弱了免疫应答和诱导免疫耐受.最新研究发现,PD-L1分子是诱导型Treg(iTreg)发育和功能维持的重要分子,PD-L1信号可将初始CD4+ CD25-T细胞转化成iTreg,发挥免疫抑制作用.对PD-1信号通道的研究可为抑制肿瘤免疫逃逸临床应用中肿瘤的免疫治疗提供新的理论依据和更好的治疗方法.     

小鼠Egr-1基因调控序列的克隆及其辐射诱导特性的鉴定

共刺激信号是激发有效的细胞免疫应答所必需的.B7分子家族及CD28/CTLA-4等刺激分子在共刺激信号的传递过程中起着重要的作用.T细胞表面CD28与APC细胞表面B7分子结合似乎提供了T细胞激活所需的主要共刺激信号.T细胞表面有多种膜表面分子,这是T细胞识别抗原,与其它免疫细胞相互作用,接受信号刺激等的物质基础,也是鉴别和分离T细胞和T细胞亚群的重要依据.由于共刺激信号的产生和传导,介导靶细胞凋亡可人为调节免疫应答使之增强或抑制.本研究将分析McAb诱导PBLs细胞膜分子表达及肝癌细胞凋亡的相关性.这可能为肿瘤免疫治疗提供新的线索.1 材料与方法1.1 淋巴细胞的分离培养正常人外周血(PBLs)100ml(广州血液中心),2     

T细胞免疫球蛋白黏蛋白分子-3 在肿瘤免疫中的作用和机制

应用单克隆抗体阻断PD-1、CTLA-4 等免疫检查点已在肿瘤免疫治疗中取得了一定成效,但尚有部分患者对免疫检查点阻断剂疗效不佳,其机制可能为存在其他抑制性旁路。T细胞免疫球蛋白黏蛋白分子-3(T cell immunolobulin and mucin-containing protein-3,TIM-3)是一种可表达于多种免疫细胞,并具有重要调控作用的免疫检查点分子。已有研究报道多种肿瘤外周血和肿瘤浸润性T细胞中存在TIM-3 高表达,并与预后不良相关。抗肿瘤免疫中,高表达TIM-3 的T细胞、DC及单核巨噬细胞,可抑制肿瘤免疫应答。临床前研究显示,抗TIM-3 单抗联合抗PD-1 单抗可发挥协同抗肿瘤效应。TIM-3 单克隆抗体已进入临床试验阶段。然而,TIM-3 在调控免疫细胞中的部分功能尚待阐明,进一步理解TIM-3 的免疫调节机制有助于推动基于阻断TIM-3 抗肿瘤免疫治疗的临床应用。     

HLA-Ⅱ类抗原与妇科恶性肿瘤的研究进展

HLA-Ⅱ类抗原主要表达于专职抗原递呈细胞表面,其生物学作用是将外源性抗原肽递呈给CD4 T细胞从而参与机体的免疫应答过程.HLA-Ⅱ类抗原的等位基因具有多态性从而导致其分子的抗原决定簇不同,可能与肿瘤的遗传易感性相关.HLA-II类抗原在恶性肿瘤组织中的异常表达,与肿瘤细胞逃避免疫监视形成肿瘤转移浸润相关.本文就HLA-Ⅱ抗原在妇科恶性肿瘤方面的研究作一综述.     

PD-1/PD-L1信号途径在肿瘤免疫逃逸机制中的作用

PD-1／PD—L1作为免疫球蛋白超家族协同刺激分子的重要成员，参与自身免疫、移植免疫以及肿瘤免疫等机体免疫调节过程。PD-1是-个主要表达在活化T细胞上的抑制性受体，与其配体PD—L1结合，可显著抑制T细胞的活化和增殖，并调节细胞因子的表达和分泌。PD—L1则广泛表达在多种免疫细胞、上皮细胞以及肿瘤细胞上。目前诸多研究表明，多种人类肿瘤大量表达的PD．L1分子与患者临床病理特征及预后紧密相关，成为肿瘤检出和预后判断的新的生物学指标。肿瘤细胞通过高表达PD—L1分子，与T细胞上的受体PD-1的结合，传递负性调控信号，导致肿瘤抗原特异性T细胞的诱导凋亡和免疫无能，使肿瘤细胞逃避机体的免疫监控和杀伤。阐明PD-1／PD—L1信号转导机制在肿瘤免疫应答中的作用，并尝试将阻断该信号通路应用于肿瘤免疫治疗，对进-步拓展肿瘤治疗的思路和方法具有重要价值。     

基于免疫抑制性受体的血液肿瘤靶向免疫治疗研究

T细胞免疫功能缺陷导致多数血液肿瘤患者不能产生有效的抗肿瘤免疫应答,从而逃避宿主免疫系统的攻击,即肿瘤细胞免疫逃逸.近年来认为肿瘤免疫抑制最为重要的机制之一是CD8+T细胞的功能耗竭,主要为免疫细胞异常表达程序性死亡分子1(PD-1)和细胞毒性T淋巴细胞相关抗原(CTLA-4)等免疫抑制所介导,而阻断此通路可以使T细胞部分或全部恢复功能.文章介绍近年来血液肿瘤中PD-1和CTLA-4及二者在介导T细胞免疫耐受中的作用及其在靶向治疗研究中的进展,为血液肿瘤的免疫靶向治疗提供新的思路.     

Cancer gene therapy of adenovirus-mediated anti-4-1BB scFv in immunocompetent mice

The use of immunostimulatory molecule genes aiming at enhancing anti-tumor immunity has emerged as a new approach to treat cancers. 4-1BB signaling, an important costimulatory pathway delivering a signal for T cell activation, survival and growth, has become one of the most promising targets for cancer immunotherapy. In this work, a recombinant nonreplicative adenovirus (Ad.4-1BB scFv) carrying a single-chain Fv fragments (scFv) specific for 4-1BB gene (anti-4-1BB scFv) was generated, haracterized and explored for its stimulation of anti-tumor immunity in immunocompetent C57BL/6 mice. Ad.4-1BB scFv could efficiently infect murine hepatoma Hepa 1-6 cells and induce anti-4-1BB scFv expression on the cell surface. Moreover, Ad.4-1BB scFv did not cause obvious cytotoxicity effect on human and murine tumor cell lines (A549, PLC/PRF/5, Hepa 1-6 and TC-1) even at a high MOI, which suggested Ad.4-1BB scFv had no direct effect on tumor cells. Intratumoral injection of Ad.4-1BB scFv to established Hepa 1-6 tumors significantly suppressed the tumor growth in C57BL/6 mice. The anti-tumor effect might be mainly attributed to the anti-4-1BB scFv-mediated immune activity, as evidenced by enhanced interferon-gamma-producing splenic cells and increased lymphocytes infiltration in the tumor microenvironment. These results indicated that nonreplicative adenovirus carrying the anti-4-1BB scFv gene possessed powerful in vivo anti-tumor efficacy and might be a valuable tool for cancer immunotherapy.     

Combination therapy with cisplatin and anti-4-1BB: synergistic anticancer effects and amelioration of cisplatin-induced nephrotoxicity

Anti-4-1BB and cisplatin showed synergistic anticancer effects in the CT-26 colon carcinoma model, producing complete regression in >60% of mice with either preventive or therapeutic treatment. The tumor-free mice formed long-lasting CD8(+) T cell-dependent tumor-specific memory. Anti-4-1BB induced rapid repopulation of T and B cells from cisplatin-mediated lymphopenia and differentiation and expansion of IFN-gamma(+)CD11c(+)CD8(+) T cells. Cisplatin facilitated expansion of na?ve, effector, and memory CD8(+) T cells; combination therapy produced almost twice as many lymphoid cells as anti-4-1BB alone. Cisplatin increased 4-1BB on antigen-primed T cells and induced 4-1BB de novo on kidney tubular epithelium. Cross-linking of 4-1BB protected the T cells and kidney epithelium from cisplatin-mediated apoptosis by increasing expression of antiapoptotic molecules. Thus, cisplatin-induced 4-1BB provided a mechanism for amelioration of the lymphopenia and nephrotoxicity inherent in cisplatin treatment. We concluded that chemoimmunotherapy with anti-4-1BB and cisplatin is synergistic in tumor killing and prevention of organ-specific toxicity.     

Anti-4-1BB monoclonal antibody enhances rejection of large tumor burden by promoting survival but not clonal expansion of tumor-specific CD8+ T cells

Anti-4-1BB monoclonal antibody (mAb) has been shown to induce antitumor immunity by a CD4/CD8-dependent mechanism, but its direct effect on tumor-specific CD8+ T cells in tumor rejection is unclear. Here we used transgenic CD8+ T cells against the unmutated tumor rejection antigen P1A to analyze whether this mAb can promote CD8+ T-cell function against large tumors in the absence of CD4+ T-helper cells. RAG-2(-/-) mice were challenged with P1A-expressing plasmacytoma J558. Once tumor size reached a diameter of 0.85-1.75 cm, mice were treated with P1A-specific CD8+ CTL (P1CTL) in conjunction with anti-4-1BB mAb or control IgG. All of the mice showed a partial regression of tumor, but mice treated with anti-4-1BB mAb exhibited markedly enhanced tumor rejection, delayed tumor progression, and prolonged survival. Correspondingly, we observed a substantial increase in the number of P1CTL in anti-4-1BB mAb-treated mice. Surprisingly, anti-4-1BB mAb did not accelerate division of the tumor-specific CD8+ T cells, and the increase in tumor-specific T-cell number was due to reduced activation-induced cell death. These results indicate that anti-4-1BB mAb can promote CD8+ T cell-mediated protection against large tumors in the absence of CD4+ T-cell help by promoting P1CTL survival without increasing initial clonal expansion.     

Mechanisms involved in synergistic anticancer immunity of anti-4-1BB and anti-CD4 therapy

Anti-4-1BB-mediated anticancer effects were potentiated by depletion of CD4+ cells in B16F10 melanoma-bearing C57BL/6 mice. Anti-4-1BB induced the expansion and differentiation of polyclonal tumor-specific CD8+ T cells into IFN-gamma-producing CD11c+CD8+ T cells. The CD4+ cell depletion was responsible for facilitating immune cell infiltration into tumor tissues and removing some regulatory barriers such as T regulatory and indoleamine-2,3-dioxygenase (IDO)+ dendritic cells. Both monoclonal antibodies (mAb) contributed to the efficient induction of MHC class I molecules on the tumor cells in vivo. The effectors that mediated the anti-4-1BB effect were NKG2D+KLRG1+CD11c+CD8+ T cells that accumulated preferentially in the tumor tissues. Blocking NKG2D reduced the therapeutic effect by 20% to 26%, which may indicate that NKG2D contributes partially to tumor killing by the differentiated CD8+ T cells. Our results indicate that the combination of the two mAbs, agonistic anti-4-1BB and depleting anti-CD4, results in enhanced production of efficient tumor-killing CTLs, facilitation of their infiltration, and production of a susceptible tumor microenvironment.     

NK and CD8+ T cell-mediated eradication of poorly immunogenic B16-F10 melanoma by the combined action of IL-12 gene therapy and 4-1BB costimulation

In previous reports, systemic administration of a stimulatory monoclonal antibody directed against the 4-1BB receptor had no effect on survival or tumor burden in mice inoculated with the poorly immunogenic B16-F10 melanoma. We combined IL-12 gene transfer with 4-1BB costimulation to explore a previously noted cooperative anti-tumor effect against this model tumor. We hypothesize that the innate immune response mediated by IL-12-activated natural killer (NK) cells initiates the activation of the immune system, leading to the priming of T cells, whereas 4-1BB costimulation enhances the function of primed tumor-specific T cells. The effect of the combination therapy on the growth of subcutaneous (s.c.) tumors and pulmonary metastasis was examined. The combination therapy significantly retarded the growth of subcutaneously-inoculated tumors, and 50% of tumor-bearing mice survived with complete tumor regression. In contrast, neither IL-12 gene transfer nor anti-4-1BB antibody administration alone was as effective. Enhanced CTL activity against both B16-F10 tumor cells and TRP-2-pulsed EL4 syngeneic tumor cells was observed in tumor-bearing animals treated with the combination therapy 2 weeks after treatment and, in long-term survivors from this combination therapy, at >120 days. In a pulmonary metastatic model, only the combination therapy generated significant protection against metastasis. In vivo depletion of NK or CD8(+) but not CD4(+) subsets eliminated the protective immunity. Furthermore, NK cell depletion significantly reduced both tumor-specific CTL activity and the number of tumor-specific IFN-gamma-producing cells, suggesting that this synergistic effect requires the participation of both NK and CD8(+) T cells.     

Polarization effects of 4-1BB during CD28 costimulation in generating tumor-reactive T cells for cancer immunotherapy

Using murine tumor-draining lymph node (TDLN) cells, we investigated the polarization effect of 4-1BB (CD137) during CD28 costimulation in generating antitumor T cells. Costimulation of TDLN cells through the newly induced 4-1BB molecules, CD3, and CD28 using monoclonal antibodies significantly enhanced cell proliferation. The greater cell yield with 4-1BB signaling appeared to be related to the inhibition of activation-induced cell death. Activation of TDLN cells through 4-1BB in addition to CD3/CD28 signaling shifted T-cell responses toward a type 1 cytokine pattern because 4-1BB ligation plus CD3/CD28 stimulation significantly augmented type 1 cytokine (e.g., IFN-gamma) and granulocyte macrophage colony-stimulating factor secretion. By contrast, type 2 cytokine (e.g., interleukin 10) secretion by the activated TDLN cells was significantly reduced. The in vivo antitumor reactivity of TDLN cells activated through 4-1BB in conjunction with CD3/CD28 pathways was examined using an adoptive immunotherapy model. The number of pulmonary metastases was significantly reduced and survival was prolonged after the transfer of anti-CD3/anti-CD28/anti-4-1BB-activated TDLN cells compared with an equivalent number of cells activated without anti-4-1BB. The antitumor effect through 4-1BB involvement during CD28 costimulation was dependent on IFN-gamma production and abrogated after IFN-gamma neutralization. By contrast, interleukin 10 neutralization resulted in significantly enhanced tumor regression. These results indicate that costimulation of TDLN cells through newly induced 4-1BB and CD3/CD28 signaling can significantly increase antitumor reactivity by shifting T-cell responses toward a type 1 cytokine pattern while concomitantly decreasing type 2 responses.     

Eradication of established renal cell carcinoma by a combination of 5-fluorouracil and anti-4-1BB monoclonal antibody in mice

Renal cell carcinoma (RCC), one of the most incurable malignancies, is highly resistant to chemotherapy and radiotherapy. Cytokine immunotherapy has been the standard approach, but the overall response rate is still very low. Administration of agonistic anti-4-1BB monoclonal antibody (mAb) has been shown to induce regression of several animal tumors but its effect on RCC is unknown. We show here that monotherapy with either anti-4-1BB mAb or the cytotoxic drug, 5-fluorouracil (5-FU), has little effect on established RCC, Renca tumors, but combination therapy with anti-4-1BB mAb and 5-FU eradicates the tumors in more than 70 % of mice. The regressing tumor tissues from mice receiving the combination therapy contained more apoptotic tumor cells and tumor infiltrating lymphocytes than tumor tissues from mice receiving 5-FU or anti-4-1BB mAb monotherapy. The number of lymphocytes in the spleens and tumor- draining lymph nodes (TDLNs) of the combination therapy mice was greatly increased compared to that of control or 5-FU monotherapy mice. Mice that had recovered due to the combination therapy rapidly rejected rechallenge with the tumor, pointing to the establishment of long-lasting tumor-specific memory. Our results indicate that targeting tumors with 5-FU, and immune cells with 4-1BB stimulation, could be a useful strategy for treating incurable RCC.     

Anti-4-1BB antibody-based combination therapy augments antitumor immunity by enhancing CD11c+CD8+ T cells in renal cell carcinoma

To improve the potential treatment strategies of incurable renal cell carcinoma (RCC), which is highly resistant to chemotherapy and radiotherapy, the present study established a combination therapy with immunostimulatory factor (ISTF) and anti-4-1BB monoclonal antibodies (mAbs) to augment the antitumor response in a murine RCC model. ISTF isolated from Actinobacillus actinomycetemcomitans stimulates macrophages, dendritic cells and B cells to produce IL-6, TNF-α, nitric oxide and major histocompatibility complex class II expression. 4-1BB (CD137) is expressed in activated immune cells, including activated T cells, and is a promising target for cancer immunotherapy. The administration of anti-4-1BB mAbs promoted antitumor immunity via enhancing CD11c⁺CD8⁺ T cells. The CD11c⁺CD8⁺ T cells were characterized by high killing activity and IFN-γ-producing ability, representing a phenotype of active effector cytotoxic T lymphocytes. The present study showed that combination therapy with ISTF and anti-4-1BB mAbs promoted partial tumor regression with established RCC, but monotherapy with ISTF or anti-4-1BB mAbs did not. These effects were speculated to be caused by the increase in CD11c⁺CD8⁺ T cells in the spleen and tumor, and IFN-γ production. These insights into the effector mechanisms of the combination of ISTF and anti-4-1BB mAbs may be useful for targeting incurable RCC.     

Enhanced antitumor activity mediated by human 4‐1BB‐engineered T cells

4‐1BB (CD137) is a costimulatory molecule transiently expressed on the T‐cell surface after TCR engagement, whereas its ligand 4‐1BBL can be found on professional antigen‐presenting cells, but more importantly, also on tumor cells. As the role of the 4‐1BB/4‐1BBL pathway has emerged central to CD8⁺ T‐cell responses and survival, we sought to test its relevance in the context of genetically modified human T cells. To that end, T cells purified from healthy donors and from vaccinated‐melanoma patients were transduced to express high levels of constitutive 4‐1BB. 4‐1BB‐transduced T cells were cocultured with melanoma tumor lines and exhibited enhanced cytokine secretion, upregulation of activation markers as well as increased cytotoxicity in a chick‐chorioallantoic membrane model of human melanoma tumors. In addition, these cells expanded and proliferated at a higher rate, expressed heightened levels of the antiapoptotic molecule Bcl_XL and were also relatively insensitive to immunosuppression mediated by transforming growth factor‐β, compared to control cells. We also show that 4‐1BBL expression on the target cell is essential to 4‐1BB‐mediated functional improvement. Overall, we conclude that the modification of human T cells with 4‐1BB yields enhanced antitumor function which may have important applications in therapies based on the genetic modification of patient lymphocytes.     

Combined natural killer T-cell based immunotherapy eradicates established tumors in mice

A rational monoclonal antibody (mAb)-based antitumor therapy approach has previously been shown to eradicate various established experimental and carcinogen-induced tumors in a majority of mice. This therapy comprised an agonistic mAb reactive with tumor necrosis factor-related apoptosis-inducing ligand receptor (DR5), expressed by tumor cells, an agonistic anti-CD40 mAb to mature dendritic cells, and an agonistic anti-4-1BB mAb to costimulate CD8(+) T cells. Because agonists of CD40 have been toxic in patients, we were interested in substituting anti-CD40 mAb with other dendritic cell-maturing agents, such as glycolipid ligands recognized by invariant natural killer T (iNKT) cells. Here, we show that CD1d-restricted glycolipid ligands for iNKT cells effectively substitute for anti-CD40 mAb and reject established experimental mouse breast and renal tumors when used in combination with anti-DR5 and anti-4-1BB mAbs (termed "NKTMab" therapy). NKTMab therapy-induced tumor rejection was dependent on CD4(+) and CD8(+) T cells, NKT cells, and the cytokine IFN-gamma. NKTMab therapy containing either alpha-galactosylceramide (alpha-GC) or alpha-C-galactosylceramide (alpha-c-GC) at high concentrations induced similar rates of tumor rejection in mice; however, toxicity was observed at the highest doses of alpha-GC (>250 ng/injection), limiting the use of this glycolipid. By contrast, even very low doses of alpha-c-GC (25 ng/injection) retained considerable antitumor activity when used in combination with anti-DR5/anti-4-1BB, and thus, alpha-c-GC showed a considerably greater therapeutic index. In summary, sequential tumor cell apoptosis and amplification of dendritic cell function by NKT cell agonists represents an exciting and novel approach for cancer treatment.