关键词： 基因工程疫苗   转基因植物  

摘要： 综述了10年来转基因植物疫苗的研究进展,分析了其中存在的问题,并提出了-些提高植物疫苗表达量的策略.

关键词： 玉米   遗传育种   基因工程   现状与展望  

摘要： 综述了近年来基因工程在玉米遗传育种研究中的应用现状和潜力。展望了基因工程在玉米遗传育种研究中的广阔前景。指出了存在的问题及其发展趋势

关键词： ANTIGEN-BINDING PROTEIN   RECOMBINANT ANTIBODY   ESCHERICHIA-COLI   CARCINOMA XENOGRAFTS   FUNCTIONAL AFFINITY   FRAGMENTS   MULTIVALENT   RADIOIMMUNOTHERAPY   CANCER   PHARMACOKINETICS  

摘要： Failure of radiolabeled monoclonal antibodies (MAbs) in the treatment of solid tumors, for the most part, is a result of undesirable pharmacokinetics that lead to significant radiation exposure of normal tissues and an inadequate delivery of radiation doses to tumors. Using genetic engineering, antitumor MAbs can be optimized for desirable clinical applications. In the present study, we report the generation of a tetravalent single-chain Fv {[sc(Fv)(2)](2)} of the murine MAb CC49 that recognizes the tumor-associated glycoprotein, TAG-72. [Sc(Fv)(2)](2) was expressed as a secreted soluble protein in Pichia pastoris under the regulation of alcohol oxidase 1 promoter. The in vitro binding properties of the tetravalent construct were analyzed by solid-phase RTA and surface plasmon resonance studies using BIA core. The binding affinity constant (K-A) for the [sc(Fv)(2)](2) and CC49 IgG were similar, i.e., 1.02 x 10(8) M-1 and 1.14 x 10(8) M-1, respectively, and were 4-fold higher than its divalent scFv [sc(Fv)(2); 2.75 x 10(7) M-1]. At 6 h postadministration, the percentage of injected dose accumulated/g of LS-174T colon carcinoma xenografts was 21.3 +/- 1.3, 9.8 +/- 1.3, and 17.3 +/- 1.1 for radioiodinated [sc(Fv)(2)](2), sc(Fv)(2), and IgG, respectively. Pharmacokinetic analysis of blood clearance studies showed the elimination half-life for [sc(Fv)(2)](2), sc(Fv)(2), and IgG as 170, 80, and 330 min, respectively. The gain in avidity resulting from multivalency along with an improved biological half-life makes the tetravalent construct an important reagent for cancer therapy and diagnosis in MAb-based radiopharmaceuticals.

关键词： POLYMERASE CHAIN-REACTION   GROWTH-FACTOR RECEPTOR   MONOCLONAL-ANTIBODIES   VARIABLE REGION   MOUSE   EXPRESSION   SEQUENCE   THERAPY   HEAVY   GENES  

摘要： Several approaches have been developed to reduce the human immune response to nonhuman antibodies. However, chimeric antibodies and humanized antibodies often have decreased binding affinity. We described a new approach for reducing the immunogenicity of chimeric antibodies while maintaining the affinity. This approach seeks to prevent the recognition of murine immunogenic peptides from the antibody variable region by human lymphocytes. Putative immunogenic epitopes in the variable region are identified and subjected to site directed mutagenesis to make them human and/or to break the amphipathic motifs. The R3 antibody, which blocks the epidermal growth factor (EGF) receptor, was used as a model system to test this approach. Four segments containing possible amphipathic epitopes were found in the heavy variable domain using the program AMPHI. Six amino acids within two of these segments were substituted by the corresponding residues from a homologous human sequence. No mutations were made in the murine light variable domain. Experiments in monkeys suggested that the "detope" R3 antibody was less immunogenic than its chimeric analogue. A search for possible amphipathic epitopes in the Kabat database revealed the presence of conserved patterns in the different families of variable region sequences, suggesting that the proposed method may be of general applicability.

关键词： 大肠杆菌K88   双价基因   猪腹泻   基因工程疫苗   保护性抗原   高密度培养   适宜培养基   免疫效果   基因工程技术   大肠杆菌菌株  

摘要： 中国农科院哈尔滨兽医研究所的科研人员利用现代基因工程技术手段,人工构建出非产肠毒素性且具有K88 K99两种保护性抗原的大肠杆菌菌株,通过接种于适宜培养基发酵高密度培养。

关键词： 猪囊虫病   基因工程疫苗   生产工艺   重组抗原  

摘要： 从重组抗原的表达、复性与纯化、疫苗的配制及疫苗的质量控制等 4个方面对猪囊虫病基因工程疫苗的生产工艺进行了探索。确定重组抗原表达的最佳培养液为LB磷酸盐培养液 ,诱导剂为 10 g/L乳糖 ,并根据接种量、溶解氧、罐压、发酵时间等对发酵结果的影响 ,确定了发酵培养的最佳条件。在重组抗原的复性与纯化方面 ,工程菌的裂解条件为先用溶菌酶感作再用超声波破菌 ,超声强度为 2 40W 5次 ;包涵体的纯化先采用低浓度的尿素洗涤 2次 ,再以 5 g/LTritonX 10 0洗涤 1遍 ,包涵体纯度可达 5 0 %以上 ;重组抗原的复性以静置缓慢透析或分步稀释法为佳 ,复性液为含 2mol/L尿素、160 μmol/LPEG 40 0 0、1.0mmol/LGSH、0 .1mmol/LGSSG的 pH 9.0 5 0mmol/LTris HCl、1mmol/LEDTA缓冲液 ;重组抗原的纯化采用分子筛凝胶层析和离子交换凝胶层析的色谱组合 ,重组抗原的纯度达 90 %以上。此外对该疫苗进行了中试生产 ,共生产 7批 ,产品全部合格 ,表明该生产工艺稳定 ,可批量化生产。

关键词： 口蹄疫   疫苗   免疫   基因工程   家畜传染病  

摘要： 用FMDV疫苗免疫接种是预防口蹄疫的主要手段之一 .研制既含B细胞表位又含T细胞表位的基因工程疫苗对口蹄疫的防治具有更强的保护能力 .用化学方法合成O型口蹄疫病毒 (FMDV)外壳蛋白VP1中 2 1～ 40位肽段的T细胞表位基因 ,与 1 41～ 1 60肽段的B细胞表位基因串联后 ,与 β 半乳糖苷酶基因相连 ,构建成一重组质粒 ,并在大肠杆菌中表达出融合蛋白疫苗 .动物实验表明 ,该疫苗不仅能诱导豚鼠产生滴度很高的中和抗体 ,而且产生大量对病毒专一性T细胞 ,与不含 2 1～ 40肽段的疫苗相比 ,用该疫苗免疫的豚鼠血单个核细胞对FMDV的反应性提高 7倍以上 ,并能抵抗病毒攻击 .说明该疫苗可同时激活体液免疫及细胞免疫反应 ,有较强的保护作用 .

关键词： 基因工程双功能抗体   分子设计   表达系统  

摘要： 基因工程双功能抗体在临床肿瘤、病毒病等治疗和诊断方面具有广阔的应用前景 ,是抗体研究的热点之一。要获得有活性的双功能产物 ,关键在于分子设计及表达系统的选择。本文着重论述近年来基因工程双功能抗体在分子设计及表达研究方面的新进展。

关键词： 单链抗体   生物学特性   重组免疫毒素   导向治疗   放射免疫显像   黄瓜花叶病毒   显像定位   重组蛋白   基因工程抗体   菌体蛋白  

关键词： 基因工程疫苗   鳖病防治   免疫保护力   气单胞苗  

摘要： 基因工程疫苗是以基因工程为手段或称作DNA重组技术产生的疫苗.国内对鳖(Trionyx sinensis)疫苗的研究也有一些报道,但多集中于灭活菌苗的研制.由于嗜水气单胞菌(Aeromonas hydrophila)、温和气单胞菌(***)等存在多种血清型,限制了一般疫苗的有效使用范围,商用疫苗的开发至今仍未成功.我们在一般菌细胞苗和化学成份疫苗研究的基础上,从菌体共同保护性抗原着手,以分子生物学方法为手段,研制了鳖的基因工程疫苗.本文报道该疫苗在大田应用的中试情况.