从人源性噬菌体抗体库中筛选人抗HBsAg的Fab噬菌体抗体(摘要)

目的:从人源性噬菌体抗体库中筛选人抗HBsAg Fab噬菌体抗体。方法:用固相化HBsAg对所构建的噬菌体抗体库进行三轮淘筛,从中筛选人抗HBsAg Fab噬菌体抗体。材料:①SB培养基:每升培养基含细菌培养用胰化蛋白胨30g,酵母提取物20g,Mops 1g,pH7.0。②SOC培养基:每升培养基含细菌培养用胰化蛋白胨20g,酵母提取物5g,NaCl 0.5g,250mmol/L KCl溶液10ml,pH7.0。临用前加入2mol/L MgCl_2溶液5ml和1mol/L葡萄糖溶液20ml。③血源纯化HBsAg。④     

噬菌体展示技术构建人源性抗乙型肝炎表面抗原单链抗体库

[目的]应用噬菌体展示技术构建人源性抗乙型肝炎(乙肝)表面抗原(HBsAg)单链抗体(ScFv)库。[方法]提取经免疫具有乙肝表面抗体的正常人淋巴细胞总RNA,采用反转录、触减PCR扩增人免疫球蛋白G(IgG)重链可变区基因(VH)和轻链可变区基因(VL),用Linker连接肽经重叠PCR将VH和VL基因连接成VH-Linker-VL形式的ScFv基因。将ScFv与pCANTAB-5E载体通过相同的酶切位点连接后,转化大肠杆菌TG1,经M13K07辅助噬菌体拯救,构建成全套人源性抗HBsAg ScFv库。[结果]成功构建了人源性抗HBsAg噬菌体ScFv库。[结论]人源性HBsAg噬菌体ScFv库的构建,为进一步筛选特异性高,具有治疗作用的乙肝抗体奠定基础。     

抗-HBs的人源性噬菌体抗体库的构建

目的构建含抗－ＨＢｓ的人源性噬菌体抗体库。方法用ＲＴ－ＰＣＲ技术,从自然感染的抗－ＨＢｓ阳性的两名献血员的外周血淋巴细胞中,扩增出人抗体轻链Ｋ基因和重链Ｆｄ基因,将二基因先后克隆人ＰＣｏｍｂ３Ｈｓｓ载体中,转化大肠杆菌,再用辅助噬菌体感染。结果构建了库容量为１５×１０５的轻链基因抗体库,轻链基因插人率为５７％和库容量为５×１０５的人Ｆａｂ体库,轻、重链基因插人率为５０％。经辅助噬菌体感染,得到噬菌体滴度为５×１０１４ＣＦＵ／ｍｌ的人源性噬菌体抗体库。结论成功构建了合抗－ＨＢｓ的人源性噬菌体抗体库,为进一步筛选ＨＢｓＡｇ的人Ｆａｂ噬菌体抗体奠定了基础。     

人源性抗HBsAg噬菌体抗体的筛选及纯化

目的:获得人源性抗HBsAg抗体Fab片段。方法:用预包被HBsAg的ELISA板,从构建的人全套抗体库中筛选出针对HBsAg的噬菌体抗体。并转入大肠杆菌中表达。破裂细胞后,获得可溶性Fab片段。以羊抗人Fab抗体偶联HiTrap柱,用     

人源性抗-HBc单链噬菌体抗体库的构建

目的 构建人源性单链噬菌体抗体库，为筛选人源性抗—HBc单链抗体奠定基础。方法 利用逆转录—聚合酶链反应(RT—PCR)和噬菌体表面展示技术，直接从乙肝病毒核心抗体(抗—HBc)阳性患者淋巴细胞中提取总RNA，逆转录成cDNA；合成全套人抗体可变区引物扩增抗体可变区基因，并将重、轻链可变区基因进行拼接装配成单链抗体(ScFv)基因，重组于噬菌粒载体叶pHEN1，转化抑制型大肠埃希菌E.coliTG1，以辅助噬菌体援救后，构建成人源性单链噬菌体库。结果 成功地构建了人源性抗—HBc单链噬菌体库，库容量达10^6。结论 利用RT—PCR和噬菌体表面展示技术可以成功构建人源性单链抗体库，并达到建库标准，可进一步从中筛选人源性单链抗体。     

人源性抗日本血吸虫噬菌体抗体库的构建及初步鉴定

目的利用噬菌体抗体展示技术构建人源性抗日本血吸虫Fab段噬菌体抗体库并进行初步鉴定。方法RT-PCR从对血吸虫感染有一定抗性成年人外周血淋巴细胞中扩增出入IgG轻链和重链Fd段基因片段，将其克隆入PComb3中．构建人源性Fab段噬菌体抗体库。并用限制性内切酶酶切、序列分析、DOT-BLOT以及SDS-PAGE等方法对噬菌体抗体库进行初步鉴定。结果噬菌体抗体库的滴度为6．2×10^11／L。库容量为1．2×10^7。酶切鉴定结果显示噬菌体抗体库轻重链重组率达到66．6％，测序结果表明克隆入PComb3的是人免疫球蛋白轻链和重链基因,DOT-BLOT实验证明该抗体库表达了人源性的抗体，而SDS-PAGE证实了免疫球蛋白Fab段的可溶性表达。结论成功地构建了人源性抗日本血吸虫Fab段噬菌体抗体库，为筛选人源性抗日本血吸虫的抗体、研究这些抗体的特性和功能奠定了基础。     

大肠癌转移淋巴结构建人源性抗大肠癌噬菌体Fab抗体库

目的 构建人源性抗大肠癌噬菌体Fab抗体库.方法 术中剥取老年大肠癌患者系膜内转移淋巴结,提取细胞总RNA,逆转录合成cDNA,进行PCR,克隆于pComb3 载体,再经电转化大肠杆菌XLI-Blue菌株,形成噬菌体抗体库,最后通过免疫印记法鉴定初级抗体库中噬菌体上有Fab段的表达.结果 从系膜内转移淋巴结中扩增出650 bp重链Fd和轻链基因产物,轻链基因产物插入测得转化菌数为4.7×10~6,鉴定插入率为70%;重链Fd基因产物测得转化菌数为3.5×10~6,插入率为60%;免疫印迹法鉴定成功建立噬菌体Fab抗体库,库容量达1.4×10~6.结论 筛选大肠癌特异性抗原和相应噬菌体抗体,对大肠癌发病机制的研究以及探讨早期诊断方法有重要意义.     

全人源肝癌噬菌体单链抗体基因的克隆及活性分析

从噬菌体单链抗体库中筛选克隆全人源肝癌抗体基因并进行活性鉴定.PCR鉴定阳性重组菌中人肝癌ScFv的插入率,以肝癌细胞SMMC-7721为抗原对所建抗体库进行4轮"吸附-洗脱-扩增"的亲和筛选.将筛选后的ScFv采用ELISA法鉴定其与人肝癌细胞的结合活性.ScFv基因插入率为70%.在亲和筛选过程中,肝癌噬菌体单链抗体得到富集,收获率逐轮提高,第4轮为第一轮的381倍.利用噬菌体抗体库技术筛选出了肝癌噬菌体单链抗体,且筛选后的抗体片段与人肝癌细胞有特异性的结合活性.     

人源性老年痴呆单链噬菌体抗体库的构建

目的 构建人源性老年痴呆(AD)单链噬菌体抗体库,为进一步筛选AD相关抗原的人源性抗体奠定基础.方法 从200 ml AD病人的外周血中分离B淋巴细胞,提取总RNA,经逆转录合成总cDNA.以PCR技术,利用特定的引物分别扩增出人抗体的重链和轻链可变区基因片段(VH、VL),并分别克隆入噬菌粒pDAN5中,构建出含人单链抗体可变区(scFv)基因序列的pDAN5克隆载体,电转化感受态大肠杆菌XLI-Blue后,经辅助噬菌体M13K07超感染后回收全部重组噬菌体,构建成初级噬菌体抗体库.从抗体库中随机挑选数个克隆,提取质粒,PCR扩增目的片段后,用内切酶BstN Ⅰ消化,每个克隆经消化后的DNA指纹印迹用琼脂糖凝胶电泳分析,评价抗体库的多样性.结果 所有抗体VH和VL基因片段均得到了扩增并成功克隆及转化,经辅助噬菌体感染后,构建成初级抗体库.BstN Ⅰ消化后的DNA指纹图谱显示各克隆抗体基因各不相同,经计算构建的噬菌体抗体库容量为1.5×106.结论 利用噬菌体抗体库技术成功构建了AD病人的单链可变区噬菌体抗体库.     

Construction and selection of the natural immune Fab antibody phage display library from patients with colorectal cancer

AIM:To construct the natural immune Fab antibody phagedisplay libraries of colorectal cancer and to select antibodiesrelated with colorectal cancer.METHODS:Extract total RNA from tissue of local cancermetastasis lymph nodes of petients with colorectal cancer.RT-PCR was used to amplify the heavy chain Fd and lightchain k and the amplification products were insertedsuccessively into the vector pComb3 to construct the humanlibraries of Fab antibodies.They were then panned by phagedisplay technology.By means of Dot immunoblotting andEUSA,the libradse were identified and the Fab phageantibodies binding with antigens of colorectal cancer wereselected.RWSULTS:The amplified fragments of Fd and k gained byRT-PCR were about 650bp.Fd and k PCR products weresubsequently inserted into the vector pComb3,resulting in arecombination rate of 40% and the volume of Fab phagedisplay library reached 1.48×10~6.The libraries wereenriched about 120-fold by 3 cycles of adsorption-elution-multiplication(penning).Dot immunoblotting showed Fabexpressions on the phage libraries and ELISA showed 5clones of Fab phage antibodies which had binding activitieswith antigens of colomctal cancer.CONCLUSION:The nstuml immune Fab antibody phagedisplay libraries of colorectal cancer were constructed.Theycould he used to select the relstive antibodies of colorectalcancer.     

An hepatitis B virus surface antigen specific single chain of variable fragment derived from a natural immune antigen binding fragment phage display library is specifically internalized by HepG2.2.15 cells

Hepatitis B virus surface antigen (HBsAg), a specific antigen on the membrane of hepatitis B virus (HBV)-infected cells, provides a perfect target for therapeutic drugs. In order to mediate successful targeted delivery of these therapies, it is essential to have antibodies that recognize HBsAg with high specificity and affinity. In this report, we constructed a natural immune antigen binding fragments (Fab) antibody phage display library against HBsAg and after three rounds of panning, five Fab fragments with significant HBsAg binding ability were selected and analysed. DNA sequencing revealed that all the light chains had the same sequence, while all the Fd genes exhibited different sequences. For further application, all of the Fab antibodies were reconstructed into single chain antibodies (scFvs) and expressed in Escherichia coli BL21 cells. Indirect enzyme-linked immunosorbent assay analysis demonstrated that all five scFvs maintained a high affinity for HBsAg and could bind HBsAg on the membrane of HBV-infected cells. Indirect fluorescent staining analysis revealed that one of the scFvs (scFv15) could be internalized into HBsAg-positive HepG2.2.15 cells through clathrin-mediated endocytosis pathway. The internalizing scFv15 antibody would have great potential for the targeted delivery of therapeutics to HBV-infected cells.     

抗华支睾吸虫循环抗原Fab抗体克隆的筛选及序列分析

目的　获得抗华支睾吸虫循环抗原Fab段抗体。方法　将华支睾吸虫代谢抗原包被在固相ELISA板中 ,采用“吸附 -洗脱 -扩增”的方法 ,对已构建的抗华支睾吸虫噬菌体抗体库进行富集。从富集后的抗体库中筛选抗循环抗原抗体克隆 ,并交叉筛选鉴定其特异性。结果　从 2 0 6个克隆中筛选到阳性克隆 2 3个 ,再分别用肺吸虫、肝片虫、姜片虫和日本血吸虫脱脂全虫粗抗原进一步交叉筛选 ,最终获得特异性抗Cs -MAg阳性克隆 3个 (B0 5 ,C10和E38)。对其中 2株 (E38和B0 5 )序列分析表明它们的κ轻链V基因属于人VκⅠ (O2 )亚群 ,J基因属于Jκ1;γ链V基因属于人VHⅠ - 6 9亚群 ,D基因来自D3- 10 ,J基因则来自JH3。结论　用成虫代谢抗原直接包板 ,可以从抗体库中筛选到阳性克隆 ,构建的噬菌体抗体库是成功有效的     

人源抗HAV噬体抗体的筛选及基因序列分析

目的 获得人源性甲型肝炎病毒（ＨＡＶ）抗体,方法 应用抗体捕获的ＨＡＶ,从本实验室构建的噬菌体抗体组合文库中筛选与ＨＡＶ病毒有结合活性的人源噬菌体抗体（Ｆａｂ段）,用夹心ＥＬＩＳＡ和竞争掏实验测定其活性及特异性,结果 筛选出与ＨＡＶ病毒有结合活性的重排产物,轻链基因属Ｖｋｍ亚群,是ＤＰｋ２２和Ｊｋ４胚系基因的重排产物,ＶＨＩ亚群,是ＤＰ８８,Ｄ３－３和ＪＨ５胚系基因片段的重排产物,轻链基因属Ｖｋｍ     

Isolation of human scFv antibody fragments against ABO blood group antigens from a phage display library

BACKGROUND AND OBJECTIVES: Phage display has proven very useful for the isolation of antibodies against a number of antigens. We used this technology to isolate scFv antibody fragments against A and B red blood cell antigens. MATERIALS AND METHODS: Phages from a phage display library were selected using unmodified red blood cells as a source of antigen. Bound phages were absorbed onto cells lacking the antigen of interest and used to infect Escherichia coli cells. Phages were rescued and assayed for specificity by enzyme-linked immunosorbent assay (ELISA). RESULTS: After several rounds of panning and subtraction on red blood cells, one anti-A and one anti-B human scFv antibody fragments were isolated. CONCLUSION: Isolation of anti-A and anti-B scFv antibody fragments on whole cells is an alternative method of obtaining antibodies against native cell-surface antigens.     

肝细胞癌人源抗c-Met抗体Fab的筛选及鉴定

目的 从大容量人源Fab抗体库中筛选全人源抗c-Met抗体,并对抗体与肝癌细胞的结合活性进行初步鉴定.方法 利用Met-Fc融合蛋白对大容量人源Fab抗体库进行固相筛选,经过5轮固相筛选,随机挑选30个克隆经酶联免疫吸附法差减鉴定,阳性克隆进行可溶性表达,用c-Met表达阳性的人肝癌细胞株鉴定抗c-Met抗体Fab的结合活性.结果 Western blot、免疫荧光结果显示,c-Met分子表达于SMMC721、BEL7402人肝癌细胞膜上;从大容量人源Fab抗体库中筛选出1株抗c-Met抗体Fab(AM2-26),经免疫共沉淀、荧光激活细胞分类术、免疫荧光分析,结果显示AM2-26与人肝癌细胞表面c-Met分子有较好的结合活性.结论 从人源Fab抗体库中筛选的AM2-26能够与肝癌细胞表面c-Met分子特异性结合,为研制用于肝癌生物治疗的靶向药物,提供了候选分子.