抗人膀胱癌单克隆抗体重链可变区基因的克隆及其原核表达载体的构建

目的 克隆抗人膀胱癌单克隆抗体重链可变区基因(VH),并构建其原核表达载体。方法从能分泌抗人膀胱癌单克隆抗体的杂交瘤细胞BDI-1中提取总RNA,通过RT-PCR扩增出VHcDNA。用HindⅢ和XhoⅠ酶切纯化的RT-PCR产物和原核表达载体pET28a( ),在T4DNA连接酶作用下室温连接。重组质粒经酶切鉴定,阳性克隆测序并进行序列分析。结果扩增出VHcDNA片段,大小约为370bp,重组质粒的酶切鉴定结果与预期一致。VH基因序列长度为366bp,编码122个氨基酸。VH基因属于鼠免疫球蛋白重链11亚类。结论成功克隆出抗人膀胱癌单克隆抗体重链可变区基因,并成功构建其原核表达载体。     

抗膀胱癌单抗Fab段基因的克隆及表达

目的：克隆抗膀胱癌单抗BDI的Fab段基因并在大肠杆菌中表达。方法：用逆转录－聚合酶链反应技术（RT－PCR）,从分泌抗人膀胱癌的鼠单抗杂交瘤细胞系中克隆k链和Fd段基因,克隆到Fab表达载体中,在大肠杆菌表达噬菌体抗体和可溶Fab;运用PCR介导的定位点突变改造VH氨基端序列;用ELISA、免疫组化法等进行特异性鉴定。结果：从分泌抗膀胱癌的鼠单抗杂交瘤细胞系中克隆了重链Fd段和k链基因,在大肠杆菌中获得有抗原结合活性的噬菌体抗体和可溶性Fab的表达,但活性很弱,将VH氨基端序列矫正为亲本单抗原始序列后,明显改善了其活性,通过ELISA、免疫组化及模拟抗体库筛选证实了所获抗体片段的特异性结合及在抗体库技术中的可用性。结论：获得了功能性抗膀胱癌小分子抗体,并再次提示抗体氨基端序列对抗体活性的影响的重要性。     

抗人CD3人/鼠嵌合抗体基因的构建

为了降低鼠源抗人CD3单抗的免疫原性．增加其在人体内的生物活性及治疗作用,使该抗体能更广泛更有效地长期多次用于人体治疗肿瘤、器官移植排斥反应及自身免疫性疾病。本文采用PCR技术从分泌抗CD3单抗的杂交瘤细胞HIT3a的mRNA中分离克隆了抗体的轻重链可变区基因的cDNA。以此轻重链可变区cDNA为特异探针从HIT3a基因文库中分离带有调控序列的功能性轻重链可变区基因,并将其插入到含有人k轻链及人71重链恒定区基因的哺乳动物表达载体中成功地构建了抗人CD3人／鼠轻重链嵌合抗体基因,为研制人抗CD3入／鼠嵌合抗体完成了关键性的第一步。     

抗人血管内皮生长因子165嵌合抗体的构建及其真核表达

目的 在真核细胞中表达抗人血管内皮生长因子１６５（ｖａｓｃｕｌａｒ ｅｎｄｏｔｈｅｌｉａｌ ｇｒｏｗｔｈ ｆａｃｔｏｒ １６５,ＶＥＧＦ１６５）人／鼠嵌合抗体。方法 将抗ＶＥＧＦ１６５鼠单抗ＶｍＤ１１的轻,重甸可变区基因克隆入基因工程抗体真核表达载体中,转染二氢叶酸还原酶缺陷型中国仓鼠卵巢（ｄｉｈｙｄｒｏｆｏｌａｔｅ ｒｅｄｕｃｔａｓｅ －ｄｅｆｉｃｉｅｎｔ Ｃｈｉｎｅｓｅ ｈａｍｓｔｅｒ ｏｖａ     

抗人大肠癌单链抗体基因的克隆与表达

背景与目的：单链抗体相对于完整抗体具有免疫源性低、对肿瘤组织穿透力强的特点,日益成为肿瘤诊断和治疗的良好导向载体。本研究的目的是将抗人大肠癌单克隆抗体ND－1的重链可变区VH和轻链可变区VL基因借助一短肽序列（Gly4Ser)3进行重组,构建单链抗体基因ND－1scFv,并使其在大肠杆菌中表达。方法：采用RT－PCR技术从能够分泌ND－1单抗的鼠杂交瘤细胞中扩增VH和VL基因,通过重叠延伸拼接PCR在VH和VL基因间引入连接短肽,体外构建ND－lscFv基因,经过常规转化和筛选,将其克隆至PET－28a( )表达载体,由IPTG诱导在大肠杆菌BL21中表达为ND－lscFv与His-Tag的融合蛋白。表达产物用Ni-NTA resin亲和层析方法纯化,并采用ELISA方法检测其免疫活性。结果：序列分析表明,ND－lscFv基因全长732bp,VH354bp位于上游;VL330bp位于下游。SDS－PAGE显示,重组蛋白相对分子量30kDa,与预期结果一致。scFv表达产物以不溶性包涵体形式存在,经亲和层析纯化后蛋白纯度达94％。ELISA结果显示scFv保留了与亲本抗体ND－1相似的免疫活性。结论：成功地构建了抗人大肠癌单链抗体ND－lscFv,并在大肠杆菌中获得了较高水平的功能性表达。     

抗人CD3人/鼠嵌合抗体的表达及特性

将从HIT3a基因库分离克隆的功能性抗CD3轻重链可变区基因插入含有人k轻链及γ1重链恒定区基因的哺乳动物表达载体中,构建了抗CD3嵌合抗体基因,用Lipofectin将抗CD3人／鼠嵌合轻重链基因共转染SP2／0细胞表达,获得稳定传代和稳定表达抗CD3嵌合抗体的转染杂交瘤细胞株C-HIT3a,ELISA,免疫荧光和PCR实验证实嵌合抗体与原鼠CD3单抗有相同的特异性和亲和性。体外生物活性的初步分析表明嵌合抗体与鼠CD3单抗对人的PBMC细胞的增殖有相同类型的作用,高剂量抗体抑制人T细胞的增殖,低剂量显示明显的激活增殖作用,当与IL-2联合应用其激活增殖作用增加20倍。细胞毒实验表明嵌合CD3抗体或由该抗体介导的免疫活性细胞(CD3-AK)对多种肿瘤细胞有明显的杀伤活性,较单用IL-2或单用LAK细胞其杀伤活性增加25倍。     

抗人P185erbB2单抗C25的生物活性及其可变区基因的克隆

目的：了解抗体Ｐ１８５＾ｅｒｂＢ２单抗Ｃ２５的生物学活性,并克隆其可变区基因,为研制抗人Ｐ１８５＾ｅｒｂＢ２的人源化抗体奠定基础。方法：以细胞ＥＬＩＳＡ、免疫组化等方法分析Ｃ２５单抗的抗原结合特性,用ＭＴＴ法检测其对乳腺癌细胞ＳＫＢＢ３,及卵巢癌细胞ＳＫＯＶ３增殖的抑制作用及对化疗药的增敏作用。经ＲＴ－ＰＣＲ扩增Ｃ２５单抗的轻、重链可变区基因、克隆后进行核苷酸序列分析。结果：Ｃ２５单抗能特异结合人     

99mTc标记的抗CEA小分子嵌合抗体的体内分布与肿瘤显像

[目的]采用99mTc标记抗人CEA小分子嵌合抗体Rch24 F(ab')2,研究其在荷人结肠癌裸鼠体内的生物学分布及放射免疫显像的特征与应用价值.[方法]采用SnC12直接还原法标记抗体,快速薄层层析法(ITLC)测定抗体的标记效率、放化纯度和体外稳定性,ELISA检测标记抗体的免疫比活性.荷人结肠癌裸鼠尾静脉注射99mTc-Rch24 F(ab')2后,研究标记抗体在裸鼠体内的生物学分布,并进行肿瘤显像.[结果] 99mTc-Rch24 F(ab')2的标记率为90％,放化纯度＞95％.99mTc-Rch24 F(ab')2的放射比活为840MBq/mg,免疫比活性为65.7％.标记抗体24h时放射性脱落小于5％.荷瘤裸鼠注射99mTc-Rch24 F(ab')2 3h后即可观察到肿瘤影像,5～24h均可获得清晰的肿瘤影像,标记抗体在体内呈肿瘤靶向性分布,12h时肿瘤的摄取和多数脏器T/NT比值均达到最高水平.[结论]99mTc-Rch24 F(ab')2在体内靶向分布于结肠癌肿瘤组织,具有较高的T/NT比值并可在肿瘤局部滞留,注射99mTc-Rch24 F(ab')25h后肿瘤成像满意.99mTc-Rch24 F(ab')2在临床肿瘤的放射免疫分子显像诊断中具有良好的应用前景.     

单克隆抗体BG_6及多克隆抗体CEA对乳腺癌的联合诊断价值

测定５１例乳腺癌，１５例良性乳腺疾病及１７例各种其它良、恶性疾病，结果显示：抗人乳腺癌单克隆抗体ＢＧ＿６特异性较强，但诊断阳性率仅为７６．７％，如与多克隆抗体ＣＥＡ联合使用，可大大提高其阳性率，即两种抗体交叉阳性率可达９６％．在乳腺癌类型中，恶性度较大的单纯癌、硬癌及浸润型导管癌，ＢＧ＿６阳性率表达显著高于其它类型。对少数乳腺腺病及囊性增生症病例中出现阳性，可能反映乳腺上皮的癌变过程。     

鼻咽癌表达下调基因NASG3''''UTR可变剪接分析及其在多种肿瘤中的表达

背景与目的:采用抑制性消减杂交技术已分离获得了人鼻咽组织特异性基因NASG。本研究对人鼻咽组织特异性表达且在鼻咽癌表达下调的NASG基因3'非编码区(untranslatedregion,UTR)的可变剪接进行分析,并考察NASG基因在多种肿瘤组织中的表达。方法:在NASG基因3'UTR存在可变剪接部位的两端设计引物进行RT-PCR扩增,分离扩增产物并测序。用RT-PCR检测NASG基因在鼻咽癌中的表达,采用了肿瘤表达谱阵列(cancerprofilingarray)杂交分析NASG基因在多种肿瘤组织的表达状况。结果:NASG基因3'UTR存在3种剪接产物,NASG基因在71%的鼻咽癌活检组织中表达下调,25%的肺癌组织中表达上调,而在其他肿瘤及其配对的正常组织未见明显表达。结论:NASG基因3'UTR存在3种剪接产物,NASG基因的表达异常是鼻咽癌和肺癌发生、发展过程中重要的分子事件。     

Construction and expression of a human-mouse chimeric antibody against human bladder cancer

Human bladder cancer is one of the most common malignant diseases in urogenital system. Traditional therapies are far from successful, especially in advanced cases[1,2]. Targeted therapy with specific antibody is considered a promising strategy for the treatment of diseases as carcinoma, immune disorders and infectious diseases, and so on[3-5]. BDI-1 is an anti-human bladder cancer monoclonal antibody produced through hybridoma technique. It has undergone a series of trials with good results…     

PPO基因单克隆抗体的制备以及在恶性黑色素瘤中表达的研究

目的：制作PPO的单克隆抗体并研究其在恶性黑色素瘤中的表达。方法：利用细胞融合法制作单克隆抗体,蛋白免疫电泳法检测单克隆抗体,免疫组化法研究PPO基因在恶性黑色素瘤中的表达情况。结果：制作了PPO基因的特异性单克隆抗体,在恶性黑色素瘤中有过表达。结论：PPO抗体是一种特异性的抗体,该抗体对恶性黑色素瘤的检测有特异性。     

Imaging of colon carcinoma with 111-indium-labeled anti-CEA monoclonal antibodies (Indacea) prior to surgery

Patients with primary and/or metastatic colorectal cancer who had been scheduled for operative intervention were injected intravenously with 200 micrograms of a high-affinity anti-carcinoembryonic antigen (CEA) monoclonal antibody labeled with 2 mCi of 111-indium (Indacea). Patients were imaged by gamma camera at 24 and 48 hours. Primary tumors were identified in 3/10 cases and were not visualized in 3/10 cases. Four scans were considered equivocal. Hepatic metastases were identified as image defects in 5/13 cases and were not visualized in 8/13 cases. All tumors contained CEA by immunoperoxidase staining. In all cases, the primary tumor uptake (5.44 +/- 1.07% ID/kg) was much higher than the uptake of the adjacent fat (0.18 +/- 0.04% ID/kg). There was a direct correlation between tumor CEA content, tumor radioactivity, and the imaging of primary tumor by Indacea. High liver uptake (30.3 +/- 3.0% ID/kg), seen when scanning all patients, was the main limitation of imaging and led to photopenic visualization of hepatic metastases. These results suggest that selection of patients with colorectal carcinoma on the basis of tumor CEA content will lead to improved rates of tumor imaging by Indacea in post-surgical scanning.     

Phase III trial of 5-fluorouracil and leucovorin plus either 3H1 anti-idiotype monoclonal antibody or placebo in patients with advanced colorectal cancer.

BACKGROUND: The monoclonal antibody 3H1 mimics the external structure of the carcinoembryonic antigen (CEA). It therefore has the potential, via the anti-idiotypic network, to stimulate immune responses to CEA that may benefit colorectal cancer patients. PATIENTS AND METHODS: A total of 630 patients with previously untreated metastatic colorectal cancer were randomised in a 2:1 fashion to receive bolus 5-fluorouracil (5-FU) and leucovorin (LV) plus either 3H1 (n = 422) or placebo (n = 208). RESULTS: The addition of 3H1 to 5-FU and LV did not result in increased toxicity. Survival for the full intent-to-treat population was 14.7 months for the 3H1 arm and 15.2 months for the placebo arm (P = 0.80). Anti-CEA antibody responses were observed in 70% of patients treated with 3H1. Patients with a negative CEA response had a median survival of 8.3 months (95% CI 7.5-11.0) compared with patients with a strong response: median survival not reached (P <0.001). CONCLUSION: 3H1 is safe and effectively induces immune responses to CEA. Addition of 3H1 to 5-FU and LV was not shown to improve overall patient outcomes. However, improved survival in patients developing anti-CEA responses to 3H1 are provocative and should be studied in further clinical trials.     

Suppression of tumor growth by in vivo administration of a recombinant human-mouse chimeric monoclonal antibody

The in vivo administration of a recently described recombinant human-mouse chimeric antibody specific for a human common acute lymphocytic leukemia antigen (cALLA) caused significant inhibition of the tumorigenic growth of human leukemic cells (Manca cells, expressing cALLA on the surface) which were implanted into nude mice. Intratumor as well as intraperitoneal administration of the human-mouse chimeric antibody repressed the tumor growth of Manca cells in nude mice. In order to investigate the in vivo localization of the antibody molecules, the chimeric antibody was labeled with radioiodine (131I) and injected into nude mice transplanted with Manca cells. The labeled antibody was significantly localized in the tumor and the location of the tumor was successfully visualized by scintiphotoscanning. These results indicated that the recombinant human-mouse chimeric antibody can exert a significant antitumor effect in vivo and can be utilized for radio-immunoimaging. Since the chimeric human-mouse monoclonal antibody would be expected to have a much lower antigenicity to humans and much higher efficiency in the interaction with human effector cells, such recombinant chimeric antibodies may be beneficial for immunotherapy and immunoimaging of cancer patients.     

CLONING AND SEQUENCING OF IMMUNOGLOBULINVARIABLE－REGION GENE OF A MONOCLONALANTIBODY SPECIFIC FOR HUMANHEPATOCARCINOMA

ＣＬＯＮＩＮＧＡＮＤＳＥＱＵＥＮＣＩＮＧＯＦＩＭＭＵＮＯＧＬＯＢＵＬＩＮＶＡＲＩＡＢＬＥ－ＲＥＧＩＯＮＧＥＮＥＯＦＡＭＯＮＯＣＬＯＮＡＬＡＮＴＩＢＯＤＹＳＰＥＣＩＦＩＣＦＯＲＨＵＭＡＮＨＥＰＡＴＯＣＡＲＣＩＮＯＭＡＹａｎｇＰｉｎｇ杨萍；ＧａｏＬｅｉ高...     

Enhancement of colorectal tumor targeting using a novel biparatopic monoclonal antibody against carcinoembryonic antigen in experimental radioimmunoguided surgery.

Biparatopic CEA, carcinoembryonic antigen (MAb) was newly designed and tested as to whether it enhanced the accuracy of tumor detection by reducing non-specific binding in experimental radioimmunoguided surgery. Biparatopic MAb was prepared by using cross-linking of reduced Fab' fragments from PR1A3 and T84.66. Fifty-nine tumors from 2 human colorectal carcinoma cell lines with high (KM-12c) and low (Clone A) carcinoembryonic antigen (CEA) expression were successfully implanted subcutaneously on the backs of 42 nude mice. Tumors were localized using 125I-labeled MAbs: IgG, F(ab')(2) and Fab' of PR1A3, and biparatopic MAb of PR1A3 and T84.66. Radioactivity counted on a portable radioisotope detector correlated well with that counted on a gamma counter (p < 0.001). Accumulations of radioactivity in control mice without tumorigenesis were the greatest in PR1A3 IgG-pretreated mice and the least in biparatopic MAb-pretreated mice. Tumors of 2 cell lines did not differ in the distribution of radiolabeled MAbs. Localization indices of the tumor in various organs revealed 1.3 to 4.1 in PR1A3 IgG-pretreated mice, 2.4 to 6.6 in fragment MAbs of PR1A3-pretreated mice and 2 to 4.6 in biparatopic MAb-pretreated mice. Silver grains and immune staining were predominantly distributed in tumor cells of all types of MAb-pretreated mice. Sensitivity and specificity of tumor localization by radioimmunoguided surgery (RIGS) were the highest in the biparatopic MAb-pretreated mice (90.9% and 94.5%, respectively) and the least in the PR1A3 IgG-pretreated mice (50% and 72%). The biparatopic MAb using 2 anti-CEA MAbs against different epitopes achieved a great affinity and avidity with accurate localization of colorectal carcinoma in experimental radioimmunoguided surgery.     

A new monoclonal antibody which binds to the cytoplasm of large cell lymphomas.

We reported a new monoclonal antibody, designated FUB-1, reacting with normal and neoplastic large lymphoid cells. FUB-1 was produced using a Burkitt's lymphoma cell line (HBL-5) as an immunogen. Its immunoglobulin subtype was IgM. The determinant was not on the surface but in the cytoplasm. Western blotting analysis revealed that the molecular weight of the antigen was 52,000 dalton. In the normal lymphoid tissue, FUB-1 reacted with large lymphoid cells, but not with small or medium-sized lymphoid cells or plasma cells. In addition, the FUB-1 antigen was not found in resting cells in the peripheral blood (PB), but it was induced on mononuclear cells of PB by addition of PWM or PMA. In the B-cell lymphomas tested, FUB-1 reacted with small cleaved cell lymphomas (3/12), large cell lymphomas (7/10), Burkitt's lymphomas (4/4) and immunoblastic lymphomas (2/2), but not with small cell lymphomas (0/3) or intermediate lymphocytic lymphomas (0/8). These findings indicate that the FUB-1 antigen appears to be expressed on normal lymphoid cells during blastoid transformation and on neoplastic large lymphoid cells. FUB-1 also reacted with normal glandular epithelium and various adenocarcinomas. FUB-1 may be useful to investigate the mechanism of in vitro blastoid transformation or activation of lymphoid cells.     

哺乳动物细胞CDK2系列表达载体的构建与表达

目的：构建一系列细胞周期蛋白依赖激酶2（cyclin-dependent kinase 2,CDK2）在哺乳动物细胞的表达载体,为研究CDK2的功能和修饰提供实验材料。方法：从食管癌细胞中提取总RNA,逆转录PCR扩增CDK2编码区,然后将PCR产物克隆到T载体;扩增后的CDK2片段分别亚克隆入pcDNA3、pcDNA4、pNTAP和pEGFP等4种哺乳动物表达载体;最后,将获得的表达载体PEGFP/CDK2转染小鼠成纤维细胞NIH3T3进行初步的CDK2表达分析。结果：RT-PCR扩增获得约900 bp的目的片段,经T载体克隆和DNA序列分析,显示重组片段是人CDK2基因序列;CDK2片段分别亚克隆入上述4种载体后获得相应表达载体;运用构建的PEGFP/CDK2表达载体,在NIH3T3细胞中表达出CDK2蛋白。结论：成功构建了CDK2的哺乳动物细胞系列表达载体,并在NIH3T3细胞中成功表达目的蛋白。