重组人CD40 L功能性片段在CHO细胞中的表达

克隆人CD40 L基因功能性片段(E107-L261),并在CHO细胞中进行表达.从健康人扁桃体组织中提取总RNA,通过RT-PCR技术,扩增CD40 L胞外区cDNA功能性片段,经DNA测序证实后,将得到的片段基因插入pcDNA3.0表达载体,构建了pcDNA3.0-hCD40 L真核表达载体.将重组质粒pcDNA3.0-hCD40 L转染CHO细胞,经G418筛选出阳性细胞克隆,扩大培养,提取细胞总蛋白,用SDS-PAGE分离并western blot-ting鉴定其特异性,通过小鼠脾淋巴细胞增值实验检验其生物学活性.结果,CD40 L胞外区功能性片段(E107-L261)cDNA被正确克隆到真核表达载体pcDNA3.0中并在CHO中成功表达,具有免疫学和生物学活性.结论:真核表达载体peDNA3.0-CD40 L的成功构建并在CH0中成功表达.     

可溶性CD40基因修饰树突状细胞对实验动物淋巴细胞增殖及胞毒活性的影响

目的探讨可溶性CD40-增强绿色荧光蛋白C(sCD40-EGFP)修饰树突状细胞(DC)对实验动物免疫功能的影响,为利用DC诱导供体特异性移植免疫耐受提供实验依据。方法应用基因工程技术构建CD40胞外区与EGFP重组载体质粒pEGFP-N1/sCD40,采用脂质体转染法,将其导入DC2.4细胞株。采用荧光分光光度计和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)鉴定转染质粒pEGFP-N1/sCD40的DC培养上清;将经未修饰DC细胞及sCD40-EGFP及空载体修饰DC经腹腔注射致敏Balb/c小鼠,取单个核细胞作为反应细胞,分别以不同组DC为刺激细胞,行混合淋巴细胞培养,采用MTS比色法检测细胞增殖,乳酸脱氢酶法测定细胞毒活性。结果sCD40分子与EGFP融合基因载体构建成功,在树突状细胞中获得表达,并分泌至上清;sCD40-EGFP融合蛋白对不同组DC致敏或未致敏小鼠的同种细胞刺激的增殖反应均有明显的抑制作用,sCD40-EGFP基因修饰DC诱导不同DC致敏组小鼠淋巴细胞增殖反应均明显降低,sCD40-EGFP融合蛋白对各实验组淋巴细胞胞毒活性有显著的抑制作用,sCD40-EGFP基因修饰DC致敏组小鼠淋巴细胞胞毒活性较其余实验组明显降低。结论稳定表达sCD40-EGFP融合蛋自的DC致敏可显著降低同种小鼠淋巴细胞的增殖反应,并能诱导淋巴细胞对靶细胞的胞毒活性降低。     

OX40Ig修饰大鼠脂肪间充质干细胞的实验研究

目的构建含OX40融合蛋白(OX40Ig)基因修饰的大鼠脂肪间充质干细胞(ADSCs)即ADSCs^OX40Ig,探讨其在体外对淋巴细胞的免疫调节作用。方法构建pcDNA3.1(+)/OX40Ig融合基因表达载体,采用核转染技术转染大鼠ADSCs,Western blot检测ADSCs中OX40Ig表达水平。ADSCs与大鼠异基因淋巴细胞共培养后分为对照组(反应细胞+刺激细胞)、ADSCs组(反应细胞+刺激细胞+ADSCs)及ADSCs^OX40Ig组(反应细胞+刺激细胞+ADSCs^OX40Ig),MTT法检测淋巴细胞增殖抑制率,逆转录聚合酶链反应(RT-PCR)检测淋巴细胞内干扰素(IFN)-γ、白细胞介素(IL)-10及转化生长因子(TGF)-βmRNA表达。结果经测序鉴定验证,pcDNA3.1(+)/OX40Ig质粒构建成功,转染ADSCs后OX40Ig蛋白呈高表达;与ADSCs组比较,ADSCs^OX40Ig显著增强异基因淋巴细胞增殖抑制率(P<0.05);对照组、ADSCs组及ADSCs<...     

重组Exendin-4-胰高血糖素样肽1/IgG4(Fc)融合蛋白的表达和活性研究

目的  构建表达长效胰高血糖素样肽1（glucagon-like peptide 1,GLP-1）受体激动剂重组Exendin-4-GLP-1/IgG4(Fc)融合蛋白的质粒载体,并研究该融合蛋白的活性。方法  将编码Exendin-4-GLP-1/IgG4(Fc)的重组基因插入表达载体pOptiVEC™-TOPO^®来构建重组质粒Exendin-4-GLP-1/IgG4(Fc)-pOptiVEC™-TOPO^®。将构建的重组质粒转染CHO/DG44细胞并收获表达产物后,分别用亲和层析法和免疫印迹法对表达产物进行纯化和检测。通过胰岛素释放实验确认重组融合蛋白对INS-1细胞胰岛素分泌的影响,同时在CD1小鼠中研究该融合蛋白对血糖的调节作用。结果  转染重组质粒的CHO/DG44细胞可成功表达Exendin-4-GLP-1/IgG4(Fc)。蛋白质印迹法检测显示,纯化的表达产物的相对分子质量（M_r）与预期相符（重组融合蛋白单体和二聚体的M_r分别约为35 000和70 000）。胰岛素释放实验表明,在葡萄糖浓度恒定的情况下INS-1细胞分泌的胰岛素量随重组融合蛋白浓度的升高而增加。CD1小鼠实验显示,重组融合蛋白对链脲佐菌素诱导的糖尿病小鼠的血糖具有调节作用,Exendin-4-GLP-1/IgG4(Fc)处理的糖尿病小鼠的血糖明显低于对照糖尿病小鼠（F=3194,P＜0.01）。结论  Exendin-4-GLP-1/IgG4(Fc)具有天然GLP-1的活性,可作为GLP-1受体激动剂用于2型糖尿病的治疗。     

pcDNA3.1/hTSHR_(1043～1354 bp)重组体的构建及在中国仓鼠卵巢细胞中的表达

目的构建重组体pcDNA3.1/hTSHR1043～1354bp及在中国仓鼠卵巢细胞(CHO)表达hTSHR膜外区氨基酸314～418蛋白分子。方法提取人正常甲状腺组织总RNA,反转录后进行聚合酶链反应(PCR),将纯化的扩增产物hTSHR1043～1354bp与表达载体pcDNA3.1连接后转化TOP10E.coli感受态菌。经PCR、HindⅢ酶切和核苷酸序列测定方法鉴定插入序列和方向正确的重组质粒转染CHO细胞,并用Westernblot方法鉴定表达的蛋白。结果PCR扩增得到hTSHR膜外区C端312bp的基因片段hTSHR1043～1354bp。该片段与表达载体pcDNA3.1的连接后转化TOP10E.coli感受态菌。重组质粒经PCR、HindⅢ酶切和核苷酸序列测定方法鉴定证实hTSHR1043～1354bp片段插入序列和方向正确。重组质粒转染的CHO细胞裂解液经Westernblot可以检测出15900的蛋白条带,与预期的蛋白相对分子质量相符。结论成功构建了重组体pcDNA3.1/hTSHR1043～1354bp,其转染CHO细胞后表达159000的目的蛋白(hTSHR氨基酸314～418蛋白片段)。     

真核表达重组小鼠IL-15/Fc融合蛋白的制备和活性鉴定

目的 制备真核表达小鼠白细胞介素15(IL-15)和IgGγ1 Fc段融合蛋白,并探讨其对抗原特异性CD8+T细胞的作用.方法 运用RT-PCR方法,从B6小鼠脾细胞中分离小鼠IL-15和IgG γ1绞链区-CH2-CH3 Fc cDNA.在IL-15 3'端和Fc 5'端引入BamH I酶切位点,将IL-15和Fc直接连接,构建小鼠IL-15/Fe融合蛋白基因,再连接到真核表达质粒载体pcDNA3.1(a+)上,转化CHO-S细胞表达、纯化后,研究其活性.结果 融合蛋白486 bp的编码由162个氨基酸组成,其中含48个信号肽氨基酸的小鼠IL-15前体蛋白和由681 bp编码227个氨基酸的IgGγ1-CH2-CH3功能区构成;表达蛋白在IL-15信号肽引导下能高效分泌到培养液中,有二聚体和三聚体两种天然结构,单体分子量约50 kDa,能特异性的结合IL-15R并抑制抗原诱导的CD8+T细胞的增殖反应.结论 成功构建了小鼠IL-15/Fc融合蛋白真核表达载体,并在CHO-S细胞中得到高效表达.此融合蛋白具有较高的生物学活性,可有效地抑制抗原特异性CD8+细胞的增殖反应.     

携带人CTLA4-Ig融合基因的非增殖腺病毒载体的构建及表达

目的 研究携带人细胞毒T淋巴细胞相关抗原(CTLA)4-Ig融合基因的非增殖腺病毒载体的生物学特性.方法 构建含人CTLA4-Ig的非增殖腺病毒载体质粒pAdTrack-CMV-hCTLA4-Ig,与非增殖腺病毒骨架质粒pAdEasy共转化大肠杆菌DH5α,在细菌内同源重组,获得重组非增殖腺病毒载体质粒pAdTrack-hCTLA4-Ig,转染293细胞,经过包装、扩增、纯化后,获得携带人CTLA4-Ig融合基因的非增殖腺病毒.体外感染人近端肾小管上皮细胞株HK-2细胞,72 h后检测其外分泌性表达.结果 获得携带人CTLA4-Ig融合基因的非增殖腺病毒,滴度为6×1013空斑形成单位/毫升(pfu/ml);在其感染的人近端肾小管上皮细胞株HK-2细胞培养上清液中能检测到可溶性重组蛋白CTLA4-Ig的表达.结论 制备的重组非增殖腺病毒在体外能有效感染人近端肾小管上皮细胞株HK-2细胞,受感染细胞能表达、分泌可溶性蛋白CTLA4-Ig.     

CD137L融合蛋白真核表达载体的构建与表达

真核表达系统因具有完整的翻译后修饰、表达蛋白免疫原性较小而成为制药行业生产蛋白药物的新方向.该研究目的是构建CD137L融合基因真核表达载体,瞬时转染HEK293F细胞实现高效表达并进行蛋白纯化与活性分析.以该实验室保存的含有CD137L融合基因的质粒pET11a-FP为模板,采用PCR技术在目的基因N端添加长腹水蚤荧...     

人降钙素基因在大鼠成肌细胞中的表达与鉴定

目的 建立稳定表达人降钙素(hCT)基因的细胞株(L6),观察人降钙素基因在大鼠成肌细胞中的表达和分泌情况.方法 采用自行构建的5端融合小鼠抗体轻链基因Igκ的信号肽序列的人降钙素基因分泌性真核表达载体pcDNA3.0-Igκ-hCT,采用脂质体介导方法将人降钙素基因导入大鼠成肌细胞;对照组用pcDNA3.0空质粒转染.经G418筛选后,采用RT-PCR法和免疫细胞化学法检测人降钙素基因在大鼠成肌细胞中的表达,并用放免法检测细胞培养上清液降钙素的分泌.结果 RT-PCR法和免疫细胞化学法均能检测到人降钙素基因在大鼠成肌细胞中的表达;并在连续传代的细胞培养上清液中检测到每106个细胞24 h培养液中降钙素分泌量的平均值42.22 ng.结论 成功转染人降钙素基因真核表达载体pcDNA3.0-Igκ-hCT于大鼠成肌细胞中;该载体可在细胞中持续稳定表达,建立了稳定的人降钙素基因表达系统.     

环孢素A对冠心病患者T淋巴细胞CD40/CD40L表达的影响

目的探讨CD40/CD40L在冠心病发生发展中的作用,以及环孢素A(Cs A)对CD40/CD40L是否具有抑制作用。方法 71例冠心病或疑诊为冠心病患者分为急性心肌梗死(AMI)组19例,不稳定型心绞痛(UAP)组18例,稳定型心绞痛(SAP)组17例,正常对照(N)组17例。提取各组患者外周血单个核细胞(PBMCs),应用流式细胞术检测各组CD40/CD40L表达水平,筛选出CD40/CD40L高表达组并给予不同浓度Cs A(H1:0 mg/L;H2:0.01 mg/L;H3:0.1mg/L;H4:1 mg/L)处理细胞,流式细胞术检测处理组CD40/CD40L的表达水平。结果与N组相比,其他3组CD40表达水平均升高(均P<0.05),UAP组、AMI组较SAP组升高,UAP组与AMI组之间差异无统计学意义(P>0.05);CD40L的表达在不同病变程度组间依次升高,两两比较差异均有统计学意义(P<0.05)。AMI组CD40/CD40L表达水平最高。不同浓度Cs A处理后H1组CD40表达率高于H3组、H4组(均P<0.05)。CD40L表达率在H1组显著高于其他3组(均P<0.05)。结论 CD40/CD40L可能参与冠心病的发生发展,Cs A可通过抑制CD40/CD40L从而延缓冠心病发展及改善预后。     

On-target and direct modulation of alloreactive T cells by a nanoparticle carrying MHC alloantigen,regulatory molecules and CD47 in a murine model of alloskin transplantation

Biomimetic nanoparticles have been reported as immune modulators in autoimmune diseases and allograft rejections by numerous researchers. However, most of the therapeutics carrying antigens, toxins or cytokines underlay the mechanism of antigen presentation by cellular uptake of NPs through pinocytosis and phagocytosis. Few researches focus on the direct and antigen-specific modulation on T cells by NPs and combined use of multiple regulatory molecules. Here, polylactic-co-glycolic acid nanoparticles (PLGA-NPs) were fabricated as scaffold to cocoupling H-2K^b-Ig dimer, anti-Fas mAb, PD-L1-Fc, TGF-β and CD47-Fc for the generation of alloantigen-presenting and tolerance-inducing NPs, termed killer NPs and followed by i.v. injection into a single MHC-mismatched murine model of alloskin transplantation. Three infusions prolonged alloskin graft survival for 45 days; depleted most of H-2K^b alloreactive CD8⁺ T cells in peripheral blood, spleen and local graft, in an antigen-specific manner. The killer NPs circulated throughout vasculature into various organs and local allograft, with a retention time up to 30 h. They made contacts with CD8⁺ T cells to facilitate vigorous apoptosis, inhibit the activation and proliferation of alloreactive CD8⁺ T cells and induce regulatory T cells in secondary lymphoid organs, with the greatly minimized uptake by phagocytes. More importantly, the impairment of host overall immune function and visible organ toxicity were not found. Our results provide the first experimental evidence for the direct and on-target modulation on alloreactive T cells by the biodegradable 200-nm killer NPs via co-presentation of alloantigen and multiple regulatory molecules, thus suggest a novel antigen-specific immune modulator for allograft rejections.     

Different roles of IL-15 from IL-2 in differentiation and activation of human CD3+CD56+ NKT-like cells from cord blood in long term culture

The abundantly available source of stem cells and the low incidence of graft-versus-host disease (GVHD) made cord blood an attractive alternative source of hematopoietic stem cells for transplantation. Besides T cell and NK cell, NKT cell played an important role in low incidence of GVHD during allogeneic transplantation. IL-2 and IL-15 can stimulate T cell and NK cell proliferation, survival and activation in vitro. But they exhibited different effects on the GVHD during allogeneic transplantation. In this study, we explored the different effects of exogenous IL-2 and IL-15 on the expansion of CD3+CD56+ NKT-like cells by in vitro long term culture of cord blood mononuclear cells (CBMCs). The results showed that CD3+CD56+ NKT-like cells were derived from CD34-CD56- CBMCs and IL-2 improved CD3+CD56+ NKT-like cell expansion more strongly than IL-15. Interestingly, CD3+CD56+ NKT-like cells from IL-15-cocultured CBMCs had significantly lower apoptotic frequency and higher levels of activation markers (CD161, CD25, and IFN-gamma) than those from IL-2-cocultured CBMCs. The anti-apoptotic and activating effects of IL-15 on CD3+CD56+ NKT-like cells from CBMCs might possibly explain the pathogenic role of IL-15 in GVHD during allogeneic transplantation.     

胞红蛋白在CHO细胞中的表达及其抗氧化活性研究

构建胞红蛋白(Cytoglobin,CYGB)真核表达载体,并在CHO细胞中进行表达。通过PCR技术扩增了CYGB基因序列,并将CYGB基因序列定向插入pcDNA3.1(+)表达载体中,构建了pcDNA3.1-CYGB真核表达载体。将重组表达载体pcDNA3.1-CYGB转染CHO细胞,经G418筛选出阳性细胞株。培养、收集细胞,提取细胞总蛋白,经Western Bloting鉴定证明CYGB表达。通过H2O2(800μmol/L)诱导的氧化应激损伤实验,检验CYGB的抗氧化活性,与对照组相比,CYGB表达细胞株提高了细胞内超氧化物酶(SOD)的活力,显著的提高了细胞在H2O2诱导的氧化应激下的存活率。研究结果表明,真核表达载体pcDNA3.1-CYGB构建成功,CYGB在真核细胞CHO中成功表达。     

Cyclic AMP differentially modulates CD40L expression on human nai;ve and memory CD4(+) T cells

Although differences in nai;ve and memory T cell signaling have been recognized, how these differences relate to cell regulation and function is not well understood. In this study, we investigated CD40 ligand (CD40L) regulation by cyclic AMP (cAMP) and prostaglandin E(2) (PGE(2)) and observed differential effects depending upon the cell subset and mode of activation. cAMP inhibited CD3-induced CD40L in both nai;ve and memory subsets, although greater inhibition was observed in memory cells. With CD3/CD28 costimulation, cAMP inhibited CD40L in memory cells but had a minimal effect on nai;ve cells. In primed T cells, cAMP increased CD40L on nai;ve cells but inhibited expression on memory cells. Differential cAMP effects appear interrelated to calcium signaling since the level of CD40L induced by calcium ionophore was increased by cAMP in both cell subsets, although nai;ve cells were more calcium responsive. Calcium-dependent calcineurin activity appeared necessary for CD40L expression, although no interaction of calcineurin and cAMP regulation was demonstrable. In contrast, inhibitors of Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) blocked cAMP effects to increase CD40L and resulted in marked CD40L inhibition. The importance of CaMKIV in cAMP regulation was confirmed by transfection studies using a dominant negative CaMKIV construct. We conclude that cAMP differentially regulates CD40L expression in a manner that appears dependent upon CaMKIV activation. In view of the central role of CD40L expression in immunity as well as the pathophysiology of common diseases, it is of interest that cAMP can either increase or decrease CD40L expression depending upon the T cell subtype and mechanism of cell activation.     

MCHR2在CHO细胞中的稳定表达及其信号通路分析

目的构建人MCHR2基因真核表达载体,在CHO细胞中进行稳定表达,并分析MCHR2介导的信号转导通路。方法采用PCR方法,以人胎脑cDNA文库为模板扩增人MCHR2基因的全长cDNA编码区序列,定向插入到真核表达载体pcDNA3·1(+),经酶切和测序鉴定后,脂质体转染法转染CHO细胞,通过G418选择培养,建立稳定转染细胞系,经RT-PCR和Western blot鉴定后,通过测定细胞内cAMP、Ca2+浓度的改变分析MCHR2的信号转导通路。结果成功构建了pcDNA3·1-MCHR2真核表达载体并稳定转入CHO细胞,建立了稳定转染细胞系,成功地表达目的基因,MCH作用于MCHR2后不影响细胞内cAMP生成,可促使细胞内钙库释放Ca2+,进而使胞内Ca2+浓度出现明显而短暂的升高,提示MCHR2的信号转导通路主要是与Gq蛋白偶联。结论人MCHR2的稳定表达和信号转导通路分析为进一步体外研究MCHR2的功能提供了良好的实验基础。     

抗VEGFR-2 scFv-Fc融合抗体的构建及其在CHO细胞中的稳定表达

目前报道的靶向VEGF/VEGFR基因工程抗体多为不含Fc片段的Fabs、cFv等小分子抗体,该文旨在CHO-k细胞中表达抗VEGFR-2 scFv-Fc融合抗体。将抗VEGFR-2 scFv(AK404)基因与含有人IgG1恒定区的真核表达载体pcDNA3.1-Fc连接,重组质粒测序后经脂质体介导转染CHO-k细胞,G418加压筛选获取稳定表达细胞株。RT-PCR、western blot检测目的基因的转录、表达。测序结果表明重组质粒构建成功,RT-PCR及western blot显示目的基因成功整合到宿主基因组并表达。最终获得可稳定表达抗VEGFR-2 scFv-Fc融合抗体的重组CHO-k细胞株,为融合抗体的大量制备和活性研究打下基础。     

CTLA4-Ig immunosuppressive activity at the level of dendritic cell/T cell crosstalk

Immunosuppressive cytotoxic T lymphocyte associated antigen-4 immunoglobulin fusion proteins (CTLA4-Ig) block the CD28:CD80/86 costimulatory pathway. On a cellular level, CTLA4-Ig is understood to dampen T cell responses. As a mechanism, CTLA4-Ig has been reported to affect dendritic cell (DC) function via inducing the immunosuppressive indoleamine 2,3 dioxygenase (IDO) pathway and promoting a DC regulatory phenotype. We here probed cellular mechanisms of CTLA4-Ig immunoregulation in an allogeneic setting using C57BL/6 splenic or bone marrow derived DCs (BMDCs) as stimulators of allogeneic Balb/c derived T cells. To address whether CTLA4-Ig immunosuppression affected DCs, we pre-exposed C57BL/6 splenic or BMDCs to CTLA4-Ig and removed unbound CTLA4-Ig before co-culture with allogeneic T cells. CTLA4-Ig disappeared rapidly (within 4 h) from the cell membrane by combined internalization and dissociation. These CTLA4-Ig pre-exposed DCs were fully capable of stimulating allogeneic T cell proliferation, suggesting that CTLA4-Ig does not impair the DC stimulatory capacity. Only the presence of CTLA4-Ig during DC/T cell co-culture resulted in the expected inhibition of proliferation. C57BL/6 splenic or BMDCs exposed to CTLA4-Ig did not display IDO activity. We conclude that CTLA4-Ig immunosuppressive activity does not depend on a DC regulatory phenotype but on its presence during DC/T cell interaction.     

结核分枝杆菌Ag85B真核表达质粒的构建及其表达

目的：构建结核分枝杆菌Ag85B真核表达质粒并表达。方法：从结核分枝杆菌（H37Rv）基因组中扩增出Ag85B编码基因，经限制性内切酶消化后，定向克隆入pcDNA3.1( )中。采用脂质体法将pcDNA/Ag85B转染COS－7细胞，采用RT－PCR、ELISA和斑点印迹法检测其表达。结果：扩增出Ag85B基因，经双向DNA序列测定，与Genbank注泵的序列一致；重组质粒转染COS－7细胞后经检测证实，该基因能在真核细胞中表达。结论：成功地构建了pcDNA/Ag85B质粒，其在真核细胞中表达的蛋白具有良好的抗原性。