血管生成抑素的原核表达及多克隆抗体的制备

目的:在原核系统中表达并纯化人血管生成抑素（angiostatin）,制备鼠抗人血管生成抑素多克隆抗体。方法:设计引物扩增angiostatin的cDNA,然后亚克隆入原核表达载体pQE,并转化入大肠杆菌BL21中诱导表达并纯化,再用纯化的人血管生成抑素免疫小鼠并制备多抗。结果:通过重组质粒酶切和测序分析等方法,筛选出重组阳性克隆,转化入大肠杆菌BL21中诱导表达并纯化成功,再利用纯化的人血管生成抑素制备成功鼠抗人血管生成抑素多克隆抗体。结论:表达产物及多克隆抗体为下阶段深入研究提供了重要的实验材料。     

癌基因LMO3的原核表达及多克隆抗体的制备及应用

目的:制备抗神经特异性表达的癌基因LMO3的多克隆抗体,进行LMO3分子检测和功能研究.方法:采用RT-PCR方法扩增LMO3的基因序列,构建其原核表达载体pET32a-LMO3.在大肠埃希菌中诱导融合蛋白表达,SDS-PAGE分离纯化原核表达的融合蛋白,PBS溶解聚丙烯酰胺凝胶颗粒中的融合蛋白,乳化后免疫新西兰兔制备多克隆抗体.采用免疫印迹、免疫组化等对该抗体的特异性进行鉴定.结果:构建的重组质粒经酶切鉴定和测序证实序列正确.经诱导表达在相对分子质量为37×103处有一条明显的蛋白条带,与预期值一致;免疫动物所得抗血清效价为1∶16 000,该抗体能够识别原核表达的LMO3蛋白及细胞内源性表达的LMO3蛋白;免疫组化显示,LMO3在SHG44胶质瘤细胞株及脑胶质瘤组织中均有表达. 结论:制备了能识别天然LMO3分子的抗LMO3的多克隆抗体,为检测LMO3分子的表达和进一步研究其功能提供了有力的工具.     

非小细胞肺癌组织中内皮抑素mRNA的转录表达及临床意义

背景与目的肿瘤生长和转移依赖于肿瘤血管形成,抑制其血管形成能够控制其生长和转移.胶原ⅩⅧ/内皮抑素(collagen ⅩⅧ/endostatin)是迄今为止最有效的内源性血管生长抑制剂之一.本研究拟探讨内皮抑素mRNA在非小细胞肺癌组织中的转录表达及其与肺癌临床病理生理特征的关系.方法用RT-PCR法检测46例非小细胞肺癌组织和14例肺良性病变组织中内皮抑素mRNA的转录表达.结果①肺癌组织中内皮抑素mRNA转录表达水平(0.872±0.071)显著高于癌旁肺组织(0.717±0.073)和肺良性病变肺组织(0.611±0.026)(P＜0.001),癌旁肺组织亦显著高于肺良性病变肺组织(P＜0.01).②肺癌组织中内皮抑素mRNA转录表达水平与肺癌原发肿瘤大小、有无远处转移、细胞分化程度和P TNM分期等均有密切关系,而与肺癌原发部位、淋巴结转移状态、组织学类型,患者性别、年龄和吸烟与否等均无明显关系.结论肺癌患者肺癌组织中存在内皮抑素mRNA转录表达水平的升高,这种升高与肺癌的发生、发展、远处转移和细胞分化不良有密切关系,因而有助于预测肺癌的恶性行为.     

血管内皮抑素研究进展

血管内皮抑素(ES)为内源性血管生成抑制剂,通过特异性抑制微血管内皮细胞迁移及诱导其凋亡,发挥抗血管生成和抑制肿瘤生长作用.临床前研究表明ES在肿瘤模型中能诱导肿瘤细胞凋亡,无宿主毒性,也未产生抗药性.Ⅰ期临床试验结果显示ES剂量达到600mg/(m2·d)时,仍未发现最大耐受剂量(MTD).ES药代动力学符合二室开放模型.ES的血浆药物浓度时间曲线下面积(AUC)、最大稳态血药浓度(CmaxSS)与给药剂量呈线性关系.ES的清除不随给药剂量、体表面积的变化而变化.Ⅱ期临床开放性研究表明,ES对于转移性神经内分泌肿瘤可能有效.ES皮下给药剂量为60mg/(m2·d)或90mg/(m2·d)时,2例(2/37,5%)患者达微效(MR),23例(23/37,62%)病灶稳定(SD).ES的中位治疗时间为24周,中位随访时间是35周,肿瘤进展中位时间(TTP)是39周.目前尚未见有关ESⅢ期临床报道.ES是非常有前途的肿瘤靶向治疗药物.     

血管内皮抑素研究进展

血管内皮抑素(ES)为内源性血管生成抑制剂,通过特异性抑制微血管内皮细胞迁移及诱导其凋亡,发挥抗血管生成和抑制肿瘤生长作用.临床前研究表明ES在肿瘤模型中能诱导肿瘤细胞凋亡,无宿主毒性,也未产生抗药性.Ⅰ期临床试验结果显示ES剂量达到600mg/(m2·d)时,仍未发现最大耐受剂量(MTD).ES药代动力学符合二室开放模型.ES的血浆药物浓度时间曲线下面积(AUC)、最大稳态血药浓度(CmaxSS)与给药剂量呈线性关系.ES的清除不随给药剂量、体表面积的变化而变化.Ⅱ期临床开放性研究表明,ES对于转移性神经内分泌肿瘤可能有效.ES皮下给药剂量为60mg/(m2·d)或90mg/(m2·d)时,2例(2/37,5%)患者达微效(MR),23例(23/37,62%)病灶稳定(SD).ES的中位治疗时间为24周,中位随访时间是35周,肿瘤进展中位时间(TTP)是39周.目前尚未见有关ESⅢ期临床报道.ES是非常有前途的肿瘤靶向治疗药物.     

重组IFN-α2a与HSV-tk/GCV系统协同作用增强对于卵巢癌细胞系SKOV3杀伤作用的体外研究

目的：在原核系统中表达并纯化人血管生成抑素（angiostatin),制备鼠抗人血管生成抑素多克隆抗体。方法：设计引物扩增angiostatin的cDNA,然后亚克隆入原核表达载体pQE,并转化入大肠杆菌BL21中诱导表达并纯化,再用纯化的人血管生成抑素免疫小鼠并制备多抗。结果：通过重组质粒酶切和测序分析等方法,筛选出重组阳性克隆,转化入大肠杆菌BL21中诱导表在并纯化成功,再利用纯化的人血管生成抑素制备成功鼠抗人血管生成抑素多克隆抗体。结论：表达产物及多克隆抗体为下阶段深入研究提供了重要的实验材料。     

血管内皮抑素的研究进展

研究表明肿瘤的形成、生长、浸润和转移的关键是肿瘤的血管化.肿瘤生长到一定体积时必然伴随着肿瘤血管新生,如果没有血管新生,大部分肿瘤则处于休眠状态.1971年,Folkman[1]最早提出肿瘤生长是血管依赖性的,他认为肿瘤血管生成是肿瘤生长和转移的形态学基础.     

重组人血管抑素的克隆、表达及活性测定

目的：研究血管抑素（ａｎｇｉｏｓｔａｔｉｎ）的临床应用价值,将其开发为多肽类药物。方法：ＲＴ－ＰＣＲ从胎儿肝脏钓取人血管抑素全编码区ｃＤＮＡ,使用Ｐｉｃｈｉａ分泌型酵母表达系统表达重组人血管抑素,重组蛋白经肝素亲和层析纯化后,以鸡胚尿囊膜法血管生成实验及小鼠创伤愈合实验检测活性。结果：重组人血管抑素在酵母系统中得到较高量表达（５ｍｇ／Ｌ）,经肝素亲和层析纯化,ＳＤＳ－ＰＡＧＥ显示分子量为４３ｋＤ。活性实验表明,重组蛋白能够抑制新生管形成、抑制伤口愈合。结论：重组人血管抑素在酵母系统中实现高效表达,并具有很好的生物学活性。     

小鼠分泌型内皮抑素原核表达载体pNZ44-ssEndostatin的构建及表达

目的: 构建带有小鼠分泌型内皮抑素(ssEndostatin)的原核表达载体pNZ44-ssEndostatin并在双歧杆菌中表达Endostatin蛋白。 方法: 利用引物设计软件oligo6.0设计引物,从pcDNA3.1-Egr1-ssEndostatin质粒上PCR扩增得到ssEndostatin基因。经测序证实获得的ssEndostatin基因序列正确后,进行粘端连接,将ssEndostatin基因链接到pNZ44原核表达载体上,构建成pNZ44-ssEndostatin重组载体,PCR、酶切鉴定正确后电转化到双歧杆菌中。然后利用ELISA法检测Endostatin表达。 结果: 测序结果证实ssEndostatin基因序列与Genebank中所公布的一致,说明ssEndostatin基因扩增正确。而且构建的质粒pNZ44-ssEndostatin的PCR、酶切鉴定结果与预测的一致,说明重组质粒pNZ44-ssEndostatin构建成功。转化后挑取阳性克隆进行菌落PCR证实重组质粒pNZ44-ssEndostatin已成功转入双歧杆菌中。ELISA法检测到转化有重组质粒pNZ44-ssEndostatin的双歧杆菌的菌体内有较高水平的Endostatin表达,且培养48h的表达量较20h的高,有氧条件下表达较缺氧条件下高,但上清中未检测到。 结论: 成功地构建了带有分泌信号的小鼠内皮抑素表达载体pNZ44-ssEndostatin,成功转入双歧杆菌中并在菌体中表达,为后续利用双歧杆菌作为工具进行Endostatin基因治疗奠定了实验基础。     

人ENO1(Enolase-α)基因的原核表达、蛋白纯化及多克隆抗体的制备

目的:构建人ENO1(human Enolase-α)基因的原核表达质粒,诱导重组蛋白的表达,利用纯化后的蛋白制备具有活性的ENO1多克隆抗体.方法:用PCR方法从胃癌MKN45细胞全基因组中扩增出目的基因ENO1,将目的基因和原核表达载体pET30a(+)分别双酶切,回收酶切产物并用T4连接酶连接,获得重组质粒pET30a(+)-ENO1.将重组质粒转入大肠埃希菌菌株BL21,经异丙基-β-D-硫代半乳糖苷(IPTG)诱导表达,用Ni-NTA亲和层析柱纯化,利用纯化的ENO1活性蛋白作为抗原免疫家兔,制备抗血清多克隆抗体,并用Western blot检测其特异性.结果:目的基因与原核表达载体经双酶切鉴定所切下的片段大小与理论值相符,测序结果表明重组人ENO1基因序列与NCBI(NM_001428.3)公布序列一致.经SDS-PAGE分析,结果显示重组蛋白的分子量约在47kDa,条带单一,无杂带出现,主要以可溶性形式存在.Western blot证实多克隆抗体制备成功.结论:成功表达、纯化了ENO1融合蛋白,制备了具有高特异性的多克隆抗体,为进一步肿瘤疫苗的研制和肿瘤标志物快速诊断的研究奠定基础.     

人CIDE-3蛋白的表达、纯化及多克隆抗体的制备

目的:制备人诱导细胞死亡的DFF45样效应因子-3(CIDE-3)蛋白兔抗人多克隆抗体并进行鉴定。方法:将原核表达载体pET28a( )/CIDE-3转化E.coli BL21(DE3),IPTG诱导表达CIDE-3蛋白,经Ni-NTA Agarose纯化后免疫新西兰白兔,获得人CIDE-3蛋白兔抗血清,并通过免疫印迹(Western blot)、酶联免疫吸附试验(ELISA)及免疫组织化学法对抗体进行鉴定。结果:成功地表达、纯化了人CIDE-3蛋白,与弗氏佐剂乳化后,免疫新西兰白兔,获得高效价的人CIDE-3蛋白兔抗血清,ELISA结果证实该抗体具有较高的亲和性,Western blot及免疫组织化学染色显示证实该抗体能够与人CIDE-3蛋白特异性结合,是一种细胞质蛋白。结论:获得了效价高、特异性较强的人CIDE-3蛋白兔抗血清,为进一步研究人CIDE-3奠定了实验基础。     

肿瘤-睾丸抗原LAGE-1基因的原核表达纯化和抗血清制备

目的:构建人肿瘤-睾丸抗原LAGE-1的原核表达质粒,表达、纯化LAGE-1融合蛋白并制备GST-LAGE-1多克隆抗体。方法:逆转录聚合酶链反应(RT-PCR)方法扩增人肝癌组织LAGE-1基因3′端片段,连入原核表达载体pGEX-4T-1( ),构建原核表达质粒pGEX-LAGE-1并测序。将该质粒转化大肠埃希菌BL21(DE3)进行诱导表达,经包涵体透析复性和谷胱甘肽巯基转移酶纯化系统分离纯化目的蛋白。用纯化的融合蛋白GST-LAGE-1免疫新西兰大白兔,间接ELISA法测定抗体效价,饱和硫酸铵沉淀法纯化抗体,并采用Western blot检测GST-LAGE-1多克隆抗体特异性。结果:RT-PCR扩增得到LAGE-1基因3′端264bp片段,测序结果与GenBank公布序列一致;成功构建pGEX-LAGE-1原核表达质粒,含有该质粒的大肠埃希菌经IPTG诱导后表达相对分子质量约为36×103的蛋白,经包涵体复性和GST融合蛋白纯化系统纯化,得到重组蛋白GST-LAGE-1,纯度达90%;制备兔抗GST-LAGE-1抗体,纯化的抗体经Western blot证实可与目的蛋白特异性结合。结论:获得了纯化的肿瘤-睾丸抗原LAGE-1重组蛋白及其特异性多克隆抗体,为进一步研究LAGE-1抗原在肿瘤免疫治疗中的作用奠定基础。     

人肺腺癌TLE1 N端Q结构域片段在原核系统表达纯化及其多克隆抗体的制备

背景与目的 TLEI是参与Wnt、Notch以及EGFR信号通路调控的一种重要蛋白.TLE1 N端Q结构域片段通过介导自身寡聚化及与LEFl结合发挥调控作用.本实验旨在构建人TLE1 N端Q区基因在大肠杆菌的融合表达载体,制备并纯化人TLEI N端Q结构域蛋白片段,制备TLEl Q结构域多克隆抗体.方法 以人肺腺癌cDNA库为模板聚合酶链反应(polymerase chain reaction, PCR)特异性扩增TLE1-Q(1-136)基因序列,与pGEX-4T-1质粒连接后转化感受态大肠杆菌E.coli.以异丙基-β-D-硫代半乳糖苷(isopropyl-β-D thiogalactoside,IPTG)诱导表达产生融合蛋白GST-TLEI-Q(1-136).经亲和层析,Thrombin酶切,FPLC纯化,SDS-PAGE鉴定目的蛋白TLE1-Q(1-136).免疫家兔,制备多克隆抗体.结果 测序证实重组表达质粒中的人TLE1 N端Q结构域基因序列正确,成功构建表达型重组质粒pGEX-4T1-TLE1-Q重组质粒转化大肠杆菌c+后,经诱导,重组蛋白GST-TLE1-021-136)得到表达.SDS-PAGE鉴定示纯化蛋白为目的蛋白人TLEl N端Q结构域片段TLE1-Q(1-136).免疫家兔后收获抗血清,ELISA显示抗体效价为1:20000,具有高度特异性.免疫印迹结果显示,制备的多抗可与TLEI.021.136)蛋白特异性结合.结论 成功构建了人TLE1 N端Q结构域重组融合蛋白表达质粒pGEX-4T1-TLE1-Q表达纯化了稳定可溶TLE1 N端Q结构域蛋白TLE1-Q(1-136),制备了人TLE1 N端Q结构域蛋白片段多克隆抗体,为进一步研究TLE1在肺癌生成中的作用奠定了基础.     

Functional identification of a non-fusion TRAIL extracellular protein and preparation of its polyclonal antibody

Human tumor necrosis factor related apoptosis inducing ligand (TRAIL) can selectively induce apoptosis in a variety of transformed cells and is currently being developed as a cancer therapeutic drug. Here we expressed the TRAIL protein including extracellular (114-281aa) without any tag protein named TRAIL-NT, and prepared anti-TRAIL polyclonal antibodies (Poly-Ab). The human TRAIL extracellular gene was amplified from PBMC and cloned into pGEM-T-Easy vector for sequence analysis. The expression vector pET-28a/TRAIL was constructed using the DNA recombinant method, and the recombinant protein without any tag protein was expressed in Escherichia coli BL21(DE3). The TRAIL-NT protein was purified by cation ion-exchange column and identified by SDS-PAGE and Western blot analysis. The proliferation inhibition activity of TRAIL-NT was detected by the MTT method, Wright-Giemsa staining assay, and FACS. The polyclonal antibody of TRAIL-NT was obtained after the BALB/C mice were immunized with purificated TRAIL-NT protein. Results showed that the target protein expressed in E. coli BL21(DE3) has the same molecular weight as that expected and could be recognized by anti-TRIAL Poly-Ab. The TRAIL-NT protein could also inhibit proliferation and induced apoptosis of Jurkat cells but no cytotoxicity to human liver cells and PBMC was observed. This preliminary research laid a solid foundation for further research on its biological activity and application in anti-tumor therapy.     

Expression of the PreS1 peptide of hepatitis B virus and preparation of its polyclonal antibody

PreS1 is a hypothetical candidate domain of L protein for hepatitis B virus (HBV) to adhere to and invade host hepatic cells. This report deals with the expression and purification of recombinant adw2 subtype of the preS1 peptide of hepatitis B virus surface antigen in Escherichia coli. The DNA fragments of the full-length or N/C terminal sequence of preS1 synthesized by PCR were inserted into the prokaryotic expression vector pGST-MOLUC, respectively. Reconstitute plasmids (named pGST-preS1, pGST-preS1N, and pGST-preS1C) were confirmed by sequencing analysis and transferred into Escherichia coli BL21(DE3). Recombinant full-length and N/C terminal of preS1 with GST tag were expressed at high levels in soluble form after induction with IPTG. The recombinant proteins were purified by a single-step affinity chromatography method. The immune reactivity of recombinant preS1 was confirmed by Western blot and virus capture assay. Furthermore, when the purified recombinant protein was used to immunize rabbit, the specific antibody titer can reach 10(-7). Thus, our successful expression system and achievement of purified recombinant preS1 protein and its polyclonal antibody lay the foundation for better understanding of the mechanism of HBV PreS1 protein in virus endocytosis and are helpful in seeking the PreS1-related protein.     

Linking antibody Fc domain to endostatin significantly improves endostatin half-life and efficacy.

PURPOSE: The half-life of the antiangiogenic molecule endostatin that has been used in clinical trial is short ( approximately 2 h). In addition, approximately 50% of the clinical grade endostatin molecules lack four amino acids at their NH(2) termini. Lack of these amino acids gives rise to a molecule that is devoid of zinc, resulting in no antitumor activity. Our goal was to develop a new version of endostatin that does not show such deficiency. EXPERIMENTAL DESIGN: A recombinant human endostatin conjugated to the Fc domain of IgG was constructed and expressed in mammalian cell culture. The presence of Fc has been shown by previous investigators to play a major role in increasing the half-life of the molecule. Fc-endostatin was tested in tumor-bearing mice, and its half-life was compared with the clinical grade endostatin. RESULTS: The antitumor dose of Fc-endostatin was found to be approximately 100 times less than the clinical grade endostatin. The half-life of Fc-endostatin in the circulation was found to be weeks rather than hours, as observed for endostatin alone. In addition, a U-shaped curve was observed for antitumor activity of endostatin as a function of endostatin concentration delivered to the animals. CONCLUSION: Fc-endostatin is a superior molecule to the original clinical endostatin. Due to its long half-life, the amount of protein required is substantially reduced compared with the clinically tested endostatin. Furthermore, in view of the U-shaped curve of efficacy observed for endostatin, we estimate that the requirement for Fc-endostatin is approximately 700-fold less than endostatin alone. The half-life of endostatin is similar to that of vascular endothelial growth factor-Trap and Avastin, two other antiangiogenic reagents. We conclude that a new clinical trial of endostatin, incorporating Fc, may benefit cancer patients.     

Prokaryotic expression of antibodies

Summary Maximizing the expression yields of recombinant whole antibodies and antibody fragments such as Fabs, single-chain Fvs and single-domain antibodies is highly desirable since it leads to lower production costs. Various eukaryotic and prokaryotic expression systems have been exploited to accommodate antibody expression but Escherichia coli systems have enjoyed popularity, in particular with respect to antibody fragments, because of their low cost and convenience. In many instances, product yields have been less than adequate and intrinsic and extrinsic variables have been investigated in an effort to improve yields. This review deals with various aspects of antibody expression in E. coli with a particular focus on single-domain antibodies. Both authors contributed equally to this work.     

抗hnRNP A2/B1多克隆抗体制备及其在非小细胞肺癌中的应用

目的:探讨自主制备抗hnRNP A2/B1多克隆抗体,对非小细胞肺癌(non-small cell lung cancer,NSCLC)的诊断、与病理特征的关系及其在预后中的价值。方法:IPTG诱导表达hnRNP A2/B1蛋白,制备兔抗人hnRNP A2/B1多克隆抗体,在45例NSCLC和16例肺炎性假瘤术后蜡块组织中,采用免疫组化的方法进行检测,并且与国外商品化的抗hnRNP A2/B1单克隆抗体进行比较,以观察自主制备的多抗在临床中的应用价值。结果:成功制备兔抗人hnRNP A2/B1多克隆抗体;应用该多抗在NSCLC组中免疫组化的表达阳性率为62.2%显著高于癌旁组织的40.0%(P=0.035)及炎性假瘤组的31.3%(P=0.033)。与临床病理特征的关系研究中发现,该蛋白高表达与年龄、吸烟呈正相关,与分化程度呈负相关;在预后中2组生存时间有差别,多抗阳性组的生存时间比阴性组的生存时间明显要短(P=0.048)。结论:获得抗hnRNP A2/B1的多克隆抗体,应用该多抗对NSCLC的诊断,病情预后具有一定的临床价值。