重组人血清白蛋白抗体检测方法的建立及确证

目的：建立一种高灵敏度、高特异性、操作简单快捷、通量高的重组人血清白蛋白（rHSA）抗体检测方法。方法：采用桥连ELISA法,即将rHSA包被于96孔板,加入待测血样及阳性对照,用辣根过氧化物酶标记的rHSA检测,显色读取D_450nm/D_570nm值：用此方法确定临界值、方法灵敏度、精密度、血药浓度对检测方法的影响,再以免疫清除法进行确证。结果：通过桥连ELISA法确定临界值为0．0492,方法灵敏度为352ng／mL,方法板间、板内精密度均小于20％,且血药中的rHSA浓度为20μg／mL时不影响抗体的检测;经免疫清除法可将假阳性样本排除,从而提高了方法的特异性．结论：建立的方法可以准确、快速地检测出rHSA的特异性抗体。     

3种检测吡咯喹啉醌的方法比较

目的:研究和比较3种检测吡咯喹啉醌(PQQ)的方法,确定各种方法的特点和适用范围。方法:设计和改进了3种检测PQQ的方法,分别为活性电泳法、光谱法和NBT-Gly法,探讨其检测限和线性范围、精密度、样品检测和加样回收率。结果:活性电泳法专一性好,具有很高的灵敏度,可检测到12.6 ng/mL PQQ,可靠但准确性较差;NBT-Gly法操作简便,可用于大量样品的检测,但重复性不佳;光谱法精密度较好,但样品中存在吸光物质时对检测结果影响较大。结论:活性电泳法、光谱法和NBT-Gly法均可用于PQQ的检测,活性电泳法适于培养上清等复杂样品的粗略定量,NBT-Gly法适于大量样品的检测,光谱法适于纯度较高的PQQ的定量。     

实时定量PCR法检测生物技术药物中宿主基因组DNA残留

利用基于SYBR GreenⅠ荧光染料的实时定量PCR方法检测酵母表达生物技术药物产品中宿主DNA残留量。该方法检测灵敏度可达到1.0 fg/μL, DNA浓度在1.0 fg/μL～1.0 ng/μL范围内线性良好,其标准曲线的相关系数为099以上。应用该方法对3批不同实验样本进行测定,宿主DNA残留量分别为8.635×105 fg/μL、6.265×102 fg/μL和1436 fg/μL 。实验表明该方法操作简便、灵敏度高,可用于生物技术药物产品中酵母DNA残留的定量测定。     

法氏囊病病毒vp2基因在酵母中的分泌表达及鉴定

应用Pichia酵母表达系统高效分泌表达了传染性传染性法氏囊病病毒vp2基因片段.首先用Primer5.0设计1对引物P1、P2,以插入IBDV vp2基因的PMD18-T-VP2载体为模板,扩增出带有终止密码子的1.4kb片段,将此片段正向亚克隆到酵母表达载体pPICZα-A上,将构建好的重组载体pPICZα-A-VP2用Sac Ⅰ内切酶线性化后,电击转化整合入Pichia PastorisX-33酵母菌,经高浓度ZeocinTM筛选、表型鉴定、诱导表达及表达产物的鉴定,得到高效表达vp2基因的酵母工程菌X-33/pPICZα-A-VP2.工程菌72h培养上清的SDS-PAGE电泳与免疫印迹结果显示,vp2基因表达产物大小约为55 kDa,比预期的41kDa大.凝胶薄层扫描结合Bradford蛋白质总含量测定结果表明,表达产物占工程菌培养上清总蛋白的28%,表达量可达23 mg/L.间接ELISA结果表明重组表达产物能够有效地区分法氏囊病病毒标准阳性与阴性血清.     

猪圆环病毒II型ORF2基因在酵母中的高效分泌表达

为了建立一种简便的检测猪圆环病毒2型(PCV2)的方法,本实验将PCV2 的ORF2 基因片段整合到巴斯德毕赤酵母(Pichia pastoris)菌株X 33染色体上,构建了X 33(pPICZa ORF2)重组工程菌。经甲醇诱导后,成功的表达出ORF2基因片段。经过Bradford 蛋白质总含量测定和凝胶薄层扫描结果表明,表达产物占重组工程菌培养上清总蛋白的58%,表达量可达47mg/ L。间接ELISA结果初步表明重组表达产物具有良好的抗原性,能够有效地区分PCV2型病毒标准阳性与阴性血清。     

法氏囊病病毒vp2基因在酵母中的分泌表达及鉴定

应用Pichia酵母表达系统高效分泌表达了传染性传染性法氏囊病病毒vp2基因片段。首先用Primer5．0设计1对引物P1、P2,以插入IBDV vp2基因的PMDl8-T-VP2载体为模板,扩增出带有终止密码子的1.4kb片段,将此片段正向亚克隆到酵母表达载体pPICZα-A上,将构建好的重组载体pPICZα-A-VP2用Sac Ⅰ内切酶线性化后,电击转化整合入Pichia PastorisX-33酵母菌,经高浓度Zeocin^TM筛选、表型鉴定、诱导表达及表达产物的鉴定,得到高效表达vp2基因的酵母工程菌X-33／pPICZα-A-VP2。工程菌72h培养上清的SDS-PAGE电泳与免疫印迹结果显示,vp2基因表达产物大小约为55kDa,比预期的41kDa大。凝胶薄层扫描结合Bradford蛋白质总含量测定结果表明,表达产物占工程菌培养上清总蛋白的28％,表达量可达23mg／L。间接ELISA结果表明重组表达产物能够有效地区分法氏囊病病毒标准阳性与阴性血清。     

猪圆环病毒Ⅱ型ORF2基因在酵母中的高效分泌表达

为了建立一种简便的检测猪圆环病毒2型(PCV2)的方法,本实验将PCV2的ORF2基因片段整合到巴斯德毕赤酵母(Pichia pastoris)菌株X-33染色体上,构建了X-33(pPICZa-ORF2)重组工程菌.经甲醇诱导后,成功的表达出ORF2基因片段.经过Bradford 蛋白质总含量测定和凝胶薄层扫描结果表明,表达产物占重组工程菌培养上清总蛋白的58%,表达量可达47mg/ L.间接ELISA结果初步表明重组表达产物具有良好的抗原性,能够有效地区分PCV2型病毒标准阳性与阴性血清.     

猪圆环病毒II型ORF2基因在酵母中的高效分泌表达

为了建立一种简便的检测猪圆环病毒2型(PCV2)的方法,本实验将PCV2的ORF2基因片段整合到巴斯德毕赤酵母(Pichia pastoris)菌株X-33染色体上,构建了X-33(pPICZa-ORF2)重组工程菌.经甲醇诱导后,成功的表达出ORF2基因片段.经过Bradford 蛋白质总含量测定和凝胶薄层扫描结果表明,表达产物占重组工程菌培养上清总蛋白的58%,表达量可达47mg/ L.间接ELISA结果初步表明重组表达产物具有良好的抗原性,能够有效地区分PCV2型病毒标准阳性与阴性血清.     

梅毒螺旋体重组抗原的表达及在梅毒血清学诊断中的应用

目的：克隆、表达梅毒螺旋体（Treponema pallidum, Tp）膜蛋白TpN47、TpN17、TpN44.5和TpN15,建立双抗原夹心ELISA法,探讨其在梅毒血清学诊断中的应用。方法：应用聚合酶链反应法（PCR）从Tp全基因组中扩增4个目的片段,克隆到载体pET-HT-JKM中,在BL21(DE3)plysS菌中诱导表达,Ni-NTA亲和层析法纯化重组蛋白,辣根过氧化物酶标记,双抗原夹心酶联免疫吸附法检测人血清中的特异性IgM和IgG抗体。结果：成功表达了4种重组蛋白用作ELISA包被和酶标抗原检测国家Tp参比血清,特异性和灵敏度均为100％;检测385份临床血清样本,结果与TPPA法相比符合率达到99％（P＜0.01）,灵敏度和特异性分别为98.2%（162/165）和99.5%（219/220）。结论：表达的4种重组抗原具有很好的生物活性,为理想的梅毒的血清学诊断用抗原。以这4种表达蛋白为基础建立的双抗原夹心ELISA法灵敏度高,特异性好,而且方法简单,结果客观,易于自动化操作,值得临床大力推广。     

OS-9基因的融合表达、纯化及多克隆抗体制备

OS 9基因广泛表达于人体多种组织 ,该基因的表达产物可能与肿瘤的发生相关 .为获得可溶性表达的OS 9蛋白 ,制备多克隆抗体 ,深入了解OS 9基因的功能 ,将OS 9基因片段克隆入组氨酸标签融合的表达载体pET2 8a中 ,IPTG诱导 ,利用金属螯合亲和层析 (MCAC)进行纯化 ,薄层扫描及Bradford法检测纯化蛋白的纯度与含量 .免疫家兔制备多克隆抗体 ,利用间接ELISA法检测抗体效价 ,Western印迹检测抗体特异性 .经表达形式分析证明 ,融合蛋白大部分可溶 .薄层扫描分析纯度可达 90 %以上 ,Bradford法检测蛋白浓度约 0 1mg ml.抗血清效价可达 1∶32 0 0以上 ,Western印迹检测证明抗体特异性良好 .经诱导表达及纯化制备出可溶的纯度较高的OS 9蛋白产物 ,并获得高效价特异性良好的多克隆抗体     

Human serum albumin from recombinant DNA technology: Challenges and strategies

Background

As the most abundant protein in the blood, human serum albumin (HSA) plays an important role in maintaining plasma oncotic pressure and fluid balance between the body's compartments. HSA is thus widely used in the clinic to treat diseases. However, the shortage of and safety issues arising from using plasma HSA (pHSA) underscore the importance of recombinant HSA (rHSA) as a promising substitute for pHSA.

Scope of review

Here, we review the production of rHSA, from expression to downstream processing, and highlight the scalability and cost-effectiveness of the two main expression platforms. We also discuss the biosafety of commercially available pharmaceutical rHSA with respect to impurities and contaminants, followed by an analysis of recent progress in preclinical and clinical trials. We emphasise the challenges of producing pharmaceutical-grade rHSA.

Major conclusions

rHSA can be highly expressed in various hosts and seems to be identical to pHSA. rHSA generated from yeast appears to be as efficient and safe as pHSA in a series of preclinical and clinical trials, whereas rHSA from rice seeds exhibits great potential for more cost-effective production. Cost-effective products with no adverse effects will likely play a vital role in future human therapeutics.

General significance

Our understanding of pharmaceutical-grade rHSA production has improved with respect to expression hosts, biochemical properties, downstream processing, and the detection and removal of impurities. However, due to the large dosages required for clinical applications, the production of sufficient quantities of rHSA still presents challenges. This article is part of a Special Issue entitled Serum Albumin.     

Summary of recombinant human serum albumin development.

The methylotrophic yeast Pichia pastoris is well known as a host strain for the production of a variety of heterologous proteins. We have used P. pastoris for the production of recombinant human serum albumin (rHSA), for which we have developed efficient and specialized downstream processes. Results from structural analysis suggest that purified rHSA possesses an identical conformation to plasma derived human albumin (pdHA) and no difference from pdHA has been observed in neo-antigenicity. Host-cell-derived impurities (i.e. Pichia yeast component, DNA and mannan) have been evaluated in the purification process as well as in the drug substance and relevant specifications established. The efficacy and safety of rHSA have been tested in clinical studies and no difference from pdHA has been found in comparative study. Such studies have confirmed rHSA to have high efficacy with little or no adverse reaction.     

重组人血清白蛋白在Pichia pastoris中的表达与纯化

为实现重组人血清白蛋白（ｒＨＳＡ）的开发,对构建的酵母工程菌Ｐｉｃｈｉａ ｐａｓｔｏｒｉｓ ＧＳ１１５／ＨＳＡ进行了表达条件的优化,摇瓶中将表达ｒＨＳＡ的量提高到１５０ｍｇ／Ｌ。经中空纤维柱浓缩、Ｐｈｅｎｙｌ－Ｓｅｐｈａｒｏｓｅ分离和抗ＨＳＡ－Ｓｅｐｈａｒｏｓｅ亲和层析纯化获得电泳纯的重组人血清白蛋白。     

重组人血清白蛋白表达研究进展

本文综述了重组人血清白蛋白在细菌,酵母,植物和动物等表达系统中表达的研究进展。用酵母表达系统,尤其是毕赤酵母,表达的重组白蛋白产量高且提取工艺简单,是其产业化最具有前途的表达系统。同时在转基因动物、植物中培养表达也具有诱人的前景。     

The effect of glycation on the structure, function and biological fate of human serum albumin as revealed by recombinant mutants

Recombinant wild-type human serum albumin (rHSA), the single-residue mutants K199A, K439A and K525A and the triple-residue mutant K199A/K439A/K525A were produced using a yeast expression system. Portions of the rHSA were glycated to different degrees (2.5-250 mM D-glucose). As detected by far-UV and near-UV CD, intrinsic tryptophan-fluorescence and probed by 1,1'-bis(4-anilino)naphthalene-5,5-disulfonic acid, the single-residue mutations had no effect on albumin conformation, whereas the triple-residue mutation and glycation caused conformational changes. The triple-residue mutation and glycation had comparable increased effects on high-affinity binding of warfarin (site I), but decreased effects on high-affinity binding of dansylsarcosine (site II) and the esterase-like activity of albumin. The relation between plasma half-lives in rats were found to be glycated rHSA (50 mM glucose)相似文献   

重组人血白蛋白临床研究进展

人血白蛋白是人血浆中最丰富的蛋白质,具有许多重要的生理特性,用途广泛。目前主要以毕赤酵母作为宿主表达的重组人血白蛋白,开发了重组人血白蛋白的纯化技术,同时对重组人血白蛋白结构进行了分析,结果表明与人血浆白蛋白基本一致。临床研究结果表明重组人血白蛋白与人血浆白蛋白有着几乎相同的疗效和安全性。综述了重组人血白蛋白的性质结构分析及酵母表达系统;重点介绍了重组人血白蛋白在临床方面研究进展。     

重组人血清白蛋白在汉逊酵母中的表达与纯化

优化人血清白蛋白（Human Serum Albumin, HSA）基因的密码子,合成基因连接到用于汉逊酵母（Hansenula polymorpha）表达的表达载体上,构建成重组人血清白蛋白（recombinant Human Serum Albumin, rHSA）表达质粒,转化汉逊酵母细胞,筛选得到的rHSA高表达细胞株HP-rHSA－C,30L发酵罐批式发酵表达量可达1.033g/L,经Streamline SP,Phenyl Bio-Sep 6FF,DEAE Sepharose层析分离获得纯化蛋白,除菌过滤后稀释,进行小鼠免疫原性分析,结果与人血清中提取的人白蛋白具有相同的抗原、抗体反应特性。     

The multimerization of hantavirus nucleocapsid protein depends on type-specific epitopes

Multimerization of the Hantaan virus nucleocapsid protein (NP) in Hantaan virus-infected Vero E6 cells was observed in a competitive enzyme-linked immunosorbent assay (ELISA). Recombinant and truncated NPs of Hantaan, Seoul, and Dobrava viruses lacking the N-terminal 49 amino acids were also detected as multimers. Although truncated NPs of Hantaan virus lacking the N-terminal 154 amino acids existed as a monomer, those of Seoul and Dobrava formed multimers. The multimerized truncated NP antigens of Seoul and Dobrava viruses could detect serotype-specific antibodies, whereas the monomeric truncated NP antigen of Hantaan virus lacking the N-terminal 154 amino acids could not, suggesting that a hantavirus serotype-specific epitope on the NP results in multimerization. The NP-NP interaction was also detected by using a yeast two-hybrid assay. Two regions, amino acids 100 to 125 (region 1) and amino acids 404 to 429 (region 2), were essential for the NP-NP interaction in yeast. The NP of Seoul virus in which the tryptophan at amino acid number 119 was replaced by alanine (W119A mutation) did not multimerize in the yeast two-hybrid assay, indicating that tryptophan 119 in region 1 is important for the NP-NP interaction in yeast. However, W119A mutants expressed in mammalian cells were detected as the multimer by using competitive ELISA. Similarly, the truncated NP of Seoul virus expressing amino acids 155 to 429 showed a homologous interaction in a competitive ELISA but not in the yeast two-hybrid assay, indicating that the C-terminal region is important for the multimerization detected by competitive ELISA. Combined, the results indicate that several steps and regions are involved in multimerization of hantavirus NP.     

Determination of Supplier-to-Supplier and Lot-to-Lot Variability in Glycation of Recombinant Human Serum Albumin Expressed in Oryza sativa

The use of different expression systems to produce the same recombinant human protein can result in expression-dependent chemical modifications (CMs) leading to variability of structure, stability and immunogenicity. Of particular interest are recombinant human proteins expressed in plant-based systems, which have shown particularly high CM variability. In studies presented here, recombinant human serum albumins (rHSA) produced in Oryza sativa (Asian rice) (OsrHSA) from a number of suppliers have been extensively characterized and compared to plasma-derived HSA (pHSA) and rHSA expressed in yeast (Pichia pastoris and Saccharomyces cerevisiae). The heterogeneity of each sample was evaluated using size exclusion chromatography (SEC), reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE). Modifications of the samples were identified by liquid chromatography-mass spectrometry (LC-MS). The secondary and tertiary structure of the albumin samples were assessed with far U/V circular dichroism spectropolarimetry (far U/V CD) and fluorescence spectroscopy, respectively. Far U/V CD and fluorescence analyses were also used to assess thermal stability and drug binding. High molecular weight aggregates in OsrHSA samples were detected with SEC and supplier-to-supplier variability and, more critically, lot-to-lot variability in one manufactures supplied products were identified. LC-MS analysis identified a greater number of hexose-glycated arginine and lysine residues on OsrHSA compared to pHSA or rHSA expressed in yeast. This analysis also showed supplier-to-supplier and lot-to-lot variability in the degree of glycation at specific lysine and arginine residues for OsrHSA. Both the number of glycated residues and the degree of glycation correlated positively with the quantity of non-monomeric species and the chromatographic profiles of the samples. Tertiary structural changes were observed for most OsrHSA samples which correlated well with the degree of arginine/lysine glycation. The extensive glycation of OsrHSA from multiple suppliers may have further implications for the use of OsrHSA as a therapeutic product.