4-1BBL胞膜外区蛋白对人外周血淋巴细胞体外活性的调节作用

目的:研究4-1BBL胞膜外区融合蛋白(ex4-1BBL)对人外周血淋巴细胞(PBL)体外活性的调节作用.方法:表达纯化人4.1BBL胞膜外区融合蛋白,台盼蓝计数观察其对淋巴细胞增殖的作用;CytoTox 96非放射性细胞毒试剂盒检测培养液的乳酸脱氢酶(LDH)水平,ELISA检测白介素-2(IL-2)水平.CytoTox 96检测其联合应用anti-CD3/anti-PgP微型双功能抗体及PBL对靶细胞K562/A02细胞的杀伤作用.结果:4-1BBL胞膜外区融合蛋白能够促进淋巴细胞增殖,减少细胞死亡,促进IL-2分泌;联合应用ex4-1BBL的淋巴细胞组的杀伤效率优于对照组.结论:ex4-1BBL可能成为增强淋巴细胞活性的重要免疫佐剂.     

免疫亲和层析法纯化抗Pgp/抗CD3双功能抗体

目的：制备可以纯化抗Pgp/抗CD3双功能抗体的免疫亲和层析柱。方法：纯化的抗抗CD3ScFv单克隆抗体与预活化的Sepharose4B偶联制成免疫亲和层析柱,采用自制的免疫亲和层析柱纯化由摇瓶发酵获得的抗Pgp/抗CD3双功能抗体,采用间接免疫荧光法测定抗CD3/抗Pgp微型双功能抗体能与Jurkat细胞及K562/A02细胞特异性结合活性。结果：成功地制备了可以纯化抗Pgp/抗CD3双功能抗体的免疫亲和层析柱,采用此柱纯化的抗体与Jurkat细胞及K562/A02细胞特异性结合的活性与带有E-tag纯化标志的抗体基本一致。结论：此介质可以替代价格高昂的E-tag亲和层析介质在纯化Pgp/抗CD3双特异双功能抗体中的应用,同时还可以避免由于E-tag纯化标志而带来的免疫原性问题,此项研究工作为抗Pgp/抗CD3双功能抗体将来在临床应用奠定了基础。     

人4-1BBL胞外区/抗CD20融合蛋白的构建和表达

目的:构建和表达人4-1BBL胞外区/抗CD20双功能融合蛋白,并测定该融合蛋白的生物学活性.方法:采用PCR和ovelap PCR方法构建人4-1BBL胞外区/抗CD20双功能融合蛋白,并用双脱氧终止法测定DNA序列;采用亲和层析法纯化该产物,并用150 g/L SDS-PAGE和Western blot鉴定纯化产物;采用FACS法鉴定纯化产物与靶细胞的结合活性.结果:DNA序列测定结果表明:人4-1BBL胞外区/抗CD20双功能融合蛋白已构建成功,表达可溶性产物的产量达4 mg/L以上,具有与Raji细胞(CD20 )和A549(4-1BB )细胞结合的活性.结论:利用融合蛋白形式,首次成功地构建了人4-1BBL胞外区/抗CD20融合蛋白,并获得较高表达.表达产物具有与相应2个靶抗原结合的活性.     

抗Pgp/抗CD3双特异双链抗体的生物学活性研究

目的　研究抗Pgp 抗CD3双特异双链抗体介导的特异性靶向杀伤活性。方法　采用亲和层析法分离纯化本室构建的抗Pgp 抗CD3双特异双链抗体可溶性表达产物 ,并用SDS PAGE、Westernblot及抗活细胞间接免疫荧光法鉴定纯化产物 ;采用51 Cr释放试验测定其介导的体外靶向杀伤活性。结果　纯化的抗Pgp 抗CD3双特异双链抗体具有与Jurkat细胞 (CD3 )和K5 6 2 A0 2 (Pgp )细胞结合的活性 ;抗Pgp 抗CD3双特异双链抗体具有介导激活的T淋巴细胞杀伤Pgp表达阳性的耐药肿瘤细胞的作用 ,杀伤作用的强弱显示出效靶比和剂量依赖关系 ,且可被CD3ScFv或PgpScFv特异性的阻断。结论　抗Pgp 抗CD3微型双功能抗体有望成为治疗耐药肿瘤 ,特别是肿瘤残留灶和微小转移灶的治疗的一种新策略。     

去除Etag标记的抗CD3/抗Pgp微型双功能抗体原核表达载体的构建及表达

目的:构建和表达不带Etag标记的抗CD3/抗Pgp微型双功能抗体(Diabody[CD3×Pgp]),并测定其生物学活性。方法:利用PCR方法构建不带Etag的Diabody[CD3×Pgp]原核表达载体,进行原核表达,制备抗抗CD3scFv亲和层析柱进行纯化,SDS-PAGE鉴定。通过间接免疫荧光法和竞争性免疫荧光结合流式细胞术(FCM)检测生物学活性。结果:无Etag的Diabody[CD3×Pgp]表达载体经测序证实其序列正确。SDS-PAGE电泳显示2条带,相对分子质量(Mr)分别为25000和26000,与预期Mr相符。去除Etag的Dia-body[CD3×Pgp]与K562/A02和Jurkat细胞结合阳性率分别为89.87%和83.95%。竞争结合实验中,与K562/A02和Jurkat细胞竞争后结合率分别为50.25%和43.78%。结论:成功构建了不带Etag的Diabody[CD3×Pgp]表达载体、进行原核表达及纯化。不带Etag的Diabody[CD3×Pgp]能特异性结合CD3和Pgp靶抗原,Etag标记去除后其生物学活性没有降低。     

二硫键稳定的抗CD3/抗Pgp微型双功能抗体稳定性研究

目的:研究二硫键稳定的抗CD3/抗Pgp微型双功能抗体(Diabody)在体外和体内的稳定性.方法:将抗CD3/抗Pgp Diabody置于37℃含0.2%人血清白蛋白(human serum albumin,HSB)的PBS中,孵育不同时间后,用流式细胞术(FACS)检测其结合活性.建立K562/A02裸鼠移植瘤模型,用Cy5荧光标记试剂盒标记抗CD3/抗Pgp Diabody,通过尾静脉注射给荷瘤裸鼠,在小动物活体成像系统上动态观察荧光信号.结果:二硫键稳定的抗CD3/抗Pgp Diabody (Ds-diabdoy)体外孵育72小时后活性无明显下降,而改造前Diabody孵育1小时后活性即开始下降,24小时后活性完全丧失.Ds-diabdoy注射后72小时仍能在肿瘤部位检测到荧光信号,而改造前Diabody在注射后24小时肿瘤部位荧光信号消失. 结论:Ds-diabdoy较改造前Diabody稳定性大大提高.     

抗人喉癌/抗CD3双功能抗体的制备及对Hep-2细胞株的杀伤作用

目的：研究制备抗人喉癌／抗CD3双功能抗体，探讨喉癌主动免疫治疗。方法：以化学方法将人喉癌及抗CD3单克隆抗体交联为双功能抗体，进行介导对肿瘤细胞的杀伤作用。结果：该双功能抗体介导效应细胞对靶细胞的杀伤率高于抗CD3的介导作用，并随着效靶比的提高而升高。结论：采用化学交联法制备的抗人喉癌／CD3双功能抗体具有潜在的临床应用价值。     

兔抗mLAIR-1胞外区抗体的制备、纯化和鉴定

目的:表达并纯化小鼠白细胞相关免疫球蛋白样受体-1(mLAIR-1)胞膜外区与人IgGFc段的融合蛋白,制备兔抗mLAIR-1胞膜外区的抗体。方法:构建真核表达载体,表达并纯化mLAIR-1-Fc融合蛋白。以mLAIR-1-Fc融合蛋白免疫家兔,用偶联mLAIR-1-Fc融合蛋白的Sepharose-4B亲和层析柱纯化多克隆抗体。用间接免疫荧光染色和流式细胞术鉴定多克隆抗体的特异性。结果:表达并纯化了mLAIR-1-hIgFc融合蛋白。以其免疫家兔,用亲和层析的方法纯化得到兔抗mLAIR-1胞膜外区的抗体,能与转染细胞和细胞表面天然mLAIR-1分子结合。结论:成功地构建了mLAIR-1胞膜外区基因的真核表达载体,表达并纯化了mLAIR-1-Fc融合蛋白。用偶联mLAIR-1-Fc融合蛋白的Sepharose-4B亲和层析柱纯化的兔抗mLAIR-1胞外区抗体,具有高特异性和高效价,为进一步研究mLAIR-1分子的结构和功能提供了新的手段。     

双表达外源性4-1BBL/IL-15的K562细胞活化外周血淋巴细胞的研究

为肿瘤过继免疫治疗开发体外激活T细胞、NK细胞的高效途径,研究双表达外源性4-1BBL和IL-15的K562细胞刺激外周血淋巴细胞活化的能力。采用分子克隆技术,分别将4-1BBL和IL-15基因插入双表达载体pVITRO-2,命名为pV4-1BBL-IL-15。经测序鉴定后,利用脂质体介导的转染及潮霉素筛选,获得稳定双表达4-1BBL、IL-15分子的K562细胞(K562/4-1BBL/IL-15)。经流式细胞仪(FACS)分选后,K562/4-1BBL/IL15细胞和K562细胞分别用丝裂霉素C处理,与外周血淋巴细胞孵育24 h,FACS检测淋巴细胞表面活化性受体CD69的表达。对NK细胞不仅同时检测活化性受体NKG2D的表达,还用乳酸脱氢酶释放法观察NK细胞受不同刺激细胞作用后,细胞毒活性的变化。结果显示受K562/4-1BBL/IL15细胞刺激后,T细胞CD69的表达无明显变化。γδT细胞CD69表达增长5倍。NK细胞CD69表达增长6倍,而NKG2D的表达增加1.5倍;NK细胞受K562/4-1BBL/IL15细胞作用72 h后,细胞毒活性明显提高。提示双表达4-1BBL/IL-15的K562细胞能够高效激活γδT细胞及NK细胞,有望用于肿瘤的过继免疫治疗。     

CD3AK细胞的诱导及其抗肿瘤作用机制的初步探讨

采用两种状态的IgG2型小鼠抗人CD3单抗,辅以小剂量外源性IL-2刺激诱导CD3AK细胞,测定其对K562,Raji及P815细胞的杀伤作用。结果发现,0.1μg/ml浓度的游离状态抗CD3单抗和10μg/ml浓度的粘附状态抗CD3单抗刺激人PBMC增殖达最强效果,其中粘附状态抗CD3单抗诱导的PBMC增殖活性明显强于激离状态抗CD3单抗;外源性IL-2能协同增强抗CD3单抗诱导PBMC增殖,但当粘附状态抗CD3单抗处于最强激活浓度时,其协同作用并不明显。实验结果显示,CD3AK细胞对三种不同性质的肿瘤细胞均具有较强的杀伤作用,其杀伤活性既有效靶细胞直接接触杀伤,又有杀伤因子介导。     

协同刺激分子4-1BB和CD28对人外周血不同T细胞亚群的激活作用

目的 :探讨 4 1BB/ 4 1BBL协同刺激信号在CD4 和CD8 T细胞活化、增殖中的作用 ,并与CD2 8/B7信号作比较。方法 :用抗CD3单抗 (mAb)刺激人外周血单个核细胞 (PBMC)。用阻断型抗 4 1BBLmAb和抗CD80mAb ,分别阻断 4 1BB/ 4 1BBL和CD2 8/B7 1协同刺激信号。利用流式细胞术 (FCM)检测CD4 T细胞、CD8 T细胞的增殖率、CD8/CD4T细胞的比值变化和细胞分泌IFN γ的情况。结果 :用抗 4 1BBLmAb和抗CD80mAb阻断相应的协同刺激途径后 ,CD4 和CD8 T细胞的增殖和细胞分泌IFN γ的水平均明显下降。培养 8d,抗CD3mAb单独刺激组CD8/CD4T细胞的比值为 1.98± 0 .0 6 ;抗 4 1BBLmAb阻断组CD8/CD4T细胞的比值下降为 0 .96±0 .0 3;而在抗CD80mAb阻断组 ,其比值上升为 2 .6 9± 0 .16。结论 :4 1BB分子可在CD4 T细胞和CD8 T细胞的活化、增殖中提供协同刺激信号。 4 1BB分子所介导的协同刺激信号 ,在CD8 T细胞活化及增殖中发挥了更为重要的作用 ;而CD2 8分子所介导的协同刺激信号则更有利于CD4 T细胞的活化     

Expression and function of 4-1BB and 4-1BB ligand on murine dendritic cells

4-1BB (CDw137) and its ligand (4-1BBL) have been implicated in cellular immune responses. To further characterize the expression and function of 4-1BBL, we newly generated an anti-mouse 4-1BBL mAb (TKS-1), which can inhibit the interaction of 4-1BBL with 4-1BB. Flow cytometric analyses using TKS-1 and an anti-mouse 4-1BB mAb indicated that 4-1BB was inducible on both CD4(+) and CD8(+) splenic T cells by stimulation with immobilized anti-CD3 mAb, but 4-1BBL was not expressed on resting or activated T cells. 4-1BBL expression was inducible on splenic B cells by stimulation with anti-IgM antibody plus anti-CD40 mAb, on peritoneal macrophages by stimulation with lipopolysaccharide (LPS) and on splenic dendritic cells (DC) by stimulation with anti-CD40 mAb or LPS. Interestingly, splenic DC expressed 4-1BB constitutively, which was down-regulated by anti-CD40 stimulation. Co-culture of splenic DC with 4-1BBL-transfected cells or 4-1BBL-expressing tumor cell lines led to cytokine (IL-6 and IL-12) production and co-stimulatory molecule up-regulation by splenic DC, indicating that 4-1BBL can directly activate DC. Moreover, IL-12 production by anti-CD40-stimulated DC was partially inhibited by TKS-1. These results suggest that 4-1BB expressed on DC may be involved in DC activation through DC--tumor interaction and DC--DC interaction.     

4-1BB-mediated expansion affords superior detection of in vivo primed effector memory CD8 T cells from melanoma sentinel lymph nodes

We have been studying the re-activation of tumor-associated antigen (TAA)-specific CD8⁺ T cells in sentinel lymph nodes (SLN) of melanoma patients upon intradermal administration of the CpG-B oligodeoxynucleotide PF-3512676. To facilitate functional testing of T cells from small SLN samples, high-efficiency polyclonal T cell expansion is required. In this study, SLN cells were expanded via classic methodologies with plate- or bead-bound anti-CD3/CD28 antibodies and with the K562/CD32/4-1BBL artificial APC system (K32/4-1BBL aAPC) and analyzed for responsiveness to common recall or TAA-derived peptides. K32/4-1BBL-expanded T cell populations contained significantly more effector/memory CD8⁺ T cells. Moreover, recall and melanoma antigen-specific CD8⁺ T cells were more frequently detected in K32/4-1BBL-expanded samples as compared with anti-CD3/CD28-expanded samples. We conclude that K32/4-1BBL aAPC are superior to anti-CD3/CD28 antibodies for the expansion of in vivo-primed specific CD8⁺ T cells and that their use facilitates the sensitive monitoring of functional anti-tumor T cell immunity in SLN.     

Expression of tumour necrosis factor (TNF) ligand superfamily co-stimulatory molecules CD30L, CD27L, OX40L, and 4-1BBL in murine hearts with acute myocarditis caused by Coxsackievirus B3.

Antigen-specific T-cells infiltrate the heart and play an important role in the myocardial damage involved in acute myocarditis and dilated cardiomyopathy. To investigate the roles of the co-stimulatory molecules CD30/CD30L, CD27/CD27L, OX40/OX40L, and 4-1BB/4-1BBL, which belong to the tumor necrosis factor (TNF) receptor/ligand superfamily, in the development of acute viral myocarditis, the expression of these molecules was first analysed in the hearts of mice with acute myocarditis induced by Coxsackievirus B3 (CVB3) in vivo. Secondly, the induction of these molecules was evaluated on cultured cardiac myocytes treated with interferon (IFN)-gamma and the interleukin (IL)-6 production by cultured cardiac myocytes was analysed by stimulation with monoclonal antibodies (MAbs) against these molecules in vitro. Thirdly, the effects of in vivo administration of anti-CD30L, anti-CD27L, anti-OX40L, or anti-4-1BBL MAb on the development of acute viral myocarditis were examined. CVB3-induced myocarditis resulted in the induction of CD30L and 4-1BBL on the surface of cardiac myocytes, confirmed by treatment with IFN-gamma in vitro. CD27L and OX40L were constitutively expressed on cardiac myocytes in vivo and in vitro. Anti-CD30L and anti-4-1BBL MAbs stimulated IL-6 production by cardiac myocytes in vitro. Furthermore, in vivo anti-4-1BBL MAb treatment significantly decreased the myocardial inflammation, whereas the other MAbs did not. These findings suggest that TNF ligand superfamily co-stimulatory molecules, especially 4-1BBL, play an important role in the development of acute viral myocarditis and raise the possibility that immunotherapy with anti-4-1BBL MAb may be of benefit in acute viral myocarditis.     

Co-stimulation with 4-1BB ligand allows extended T-cell proliferation, synergizes with CD80/CD86 and can reactivate anergic T cells

Activation of T cells requires co-stimulation, in addition to signals through the antigen-receptor complex. Antigen encounter without adequate co-stimulation results in T-cell desensitization or anergy, a mechanism of peripheral tolerance and an apparent obstacle to cancer immunotherapy. One important co-stimulatory pathway involves CD28 engagement by CD80 or CD86. However, other ligand-receptor pairs can also provide co-stimulation and may have important functions modulating the immune response. Previous reports indicated that co-stimulation using 4-1BB ligand (4-1BBL) or agonistic anti-4-1BB antibodies could prolong T-cell responses, avoid activation-induced cell death and promote anti-tumour responses in mice. To further investigate the potential for cancer immunotherapy, we studied the effects of CD80/CD86 and 4-1BBL in repeated stimulation of human T cells and asked whether 4-1BBL might be capable of reversing anergy. We expressed CD80, CD86 and 4-1BBL in A549 lung carcinoma cells using adenovirus vectors and co-cultured these with human T cells stimulated with anti-CD3 antibody. Proliferation co-stimulated by CD80 or CD86 was transient; however, 4-1BBL-co-stimulated cultures continued to proliferate for up to 5 weeks, with repeated stimulation. Combined co-stimulation with CD80/CD86 and 4-1BBL also allowed continuous proliferation at a faster rate than either signal alone. Co-stimulation with 4-1BBL did not suppress expression of the inducible, inhibitory CD80/CD86R, CTLA-4. Significantly, we show that T cells that had become non-responsive to anti-CD3, either alone or together with CD80/CD86 co-stimulation, and thus were anergic, could be reactivated to proliferate when costimulated with 4-1BBL, either alone or combined with CD80/CD86.     

人4-1BB配体基因真核表达载体的构建、表达及其体外抗肿瘤效应

目的： 构建人4-1BB配体（h4-1BBL）全长基因的真核表达载体, 并在肿瘤细胞HT-29中转染表达; 探讨人4-1BBL基因转染的肿瘤细胞体外诱导的抗肿瘤活性.方法： 用RT-PCR从Raji细胞中克隆h4-1BBL全长基因, 测序后, 构建重组真核表达载体pcDNA3.1（-）-h4-1BBL.通过脂质体法以重组载体转染HT-29细胞, 用RT-PCR检测转染细胞中h4-1BBL mRNA的表达; 用流式细胞术检测转染细胞表面h4-1BBL分子的表达.分离外周血单个核细胞（PBMC）, 用抗CD3 mAb扩增T细胞, 并与h4-1BBL基因转染及未转染的HT-29细胞混合培养.用MTT比色法检测CTL的增殖及杀伤活性; 用流式细胞术检测分泌IFN-γ的T细胞.结果： 从Raji细胞中克隆到h4-1BBL全长cDNA, 测序完全正确.构建的h4-1BBL基因真核表达载体在HT-29中获得稳定表达.与未转染的细胞相比较, h4-1BBL基因转染的肿瘤细胞HT-29能更有效地刺激T细胞活化、增殖, 促进IFN-γ分泌, 并能有效地诱导CTL产生针对野生型HT-29细胞的特异性杀伤.结论： 成功地构建pcDNA3.1（-）h4-1BBL重组真核表达载体.4-1BBL基因转染的肿瘤细胞介导的协同刺激信号, 能增强野生型肿瘤细胞的免疫原性, 诱导T细胞产生有效的抗肿瘤免疫应答.