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1.
Over the past decade, West Nile virus (WNV) has spread to all 48 of the lower United States as well as to parts of Canada, Mexico, the Caribbean, and South America, with outbreaks of neuroinvasive disease occurring annually. At present, no therapeutic or vaccine is available for human use. Epidemics of WNV and other emerging infectious disease threats demand cost-efficient and scalable production technologies that can rapidly transfer effective therapeutics into the clinical setting. We have previously reported that Hu-E16, a humanized anti-WNV mAb, binds to a highly conserved epitope on the envelope protein, blocks viral fusion, and shows promising postexposure therapeutic activity. Herein, we generated a plant-derived Hu-E16 mAb that can be rapidly scaled up for commercial production. Plant Hu-E16 was expressed at high levels within 8 days of infiltration in Nicotiana benthamiana plants and retained high-affinity binding and potent neutralizing activity in vitro against WNV. A single dose of plant Hu-E16 protected mice against WNV-induced mortality even 4 days after infection at rates that were indistinguishable from mammalian-cell-produced Hu-E16. This study demonstrates the efficacy of a plant-produced mAb against a potentially lethal infection several days after exposure in an animal challenge model and provides a proof of principle for the development of plant-derived mAbs as therapy against emerging infectious diseases.  相似文献   

2.
Quelle  FW; Caslake  LF; Burkert  RE; Wojchowski  DM 《Blood》1989,74(2):652-657
Conditions presently have been established for the high-level expression and simplified purification of recombinant human erythropoietin produced in Spodoptera frugiperda cells. Expression, as mediated by infection with a recombinant baculovirus, was accomplished in suspension culture using reduced levels of serum and media supplements experimentally determined to provide optimum levels of factor production (500,000 U/L). Purification of this recombinant human erythropoietin to virtual homogeneity (greater than or equal to 99%) was accomplished via a simple three-step procedure involving isocratic elution from DEAE-Sephacel, reverse-phase high performance liquid chromatography (HPLC) on a C4 medium, and the single-step elution of purified hormone from concanavalin A agarose. Overall, an 890-fold purification was accomplished with a recovery of 80% as assayed in vitro. Biologically, this purified erythropoietin is highly active, possessing a specific activity in vitro of 200,000 U/mg protein. Chemically, this erythropoietin (molecular weight [mol wt] 26,200) appears exceptionally uniform in its oligosaccharide constitution (30%) as contrasted with heterogeneously glycosylated erythropoietins derived from mammalian cells (mol wt 30,000 to 38,000; 40% to 50% complex-type oligosaccharide). Thus, human erythropoietin as presently produced in an insect cell line comprises not only an abundant source of highly active, readily purified hormone for studies of its mechanism of action and cell surface receptor, but also represents a uniquely homogeneous form that should prove advantageous for direct structural analyses.  相似文献   

3.
Transgenic pigs were generated that produced human protein C in their milk at up to 1 g/liter. The gene construct was a fusion gene consisting of the cDNA for human protein C inserted into the first exon of the mouse whey acidic protein gene. These results demonstrate that the mouse whey acidic protein gene contains regulatory elements that can direct cDNA expression at high levels in the pig mammary gland. Recombinant human protein C that was produced at about 380 micrograms/ml per hr in transgenic pig milk possessed anticoagulant activity that was equivalent to that of protein C derived from human plasma. These studies provide evidence that gamma-carboxylation can occur at high levels in the mammary gland of a pig.  相似文献   

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5.
高表达乙型肝炎病毒转基因小鼠的制备   总被引:14,自引:0,他引:14  
目的 制备高表达乙型肝炎病毒(HBV)转基因小鼠,为乙型肝炎研究提供较理想动物模型。方法 构建、筛选高表达HBV质粒载体。用显微注射法导入昆明鼠受精卵雄性原核,用PCR、Southern杂交、放射免疫、免疫组织化学等方法分析HBV基因在小鼠体内的整合、表达情况。结果 显微注射1456枚卵,产仔118只,整合阳性25只,11只血清HBV DNA、HBsAg阳性,其中2只血清中HBsAg含量高于1000ng/ml,且子代鼠中达到900ng/ml。肝组织免疫组化分析发现有HBsAg、HBcAg表达,未见明显病理学改变。结论 已初步获得高表达HBV转基因小鼠。  相似文献   

6.
The gene for the influenza viral PB2 protein, which recognizes and binds the 5'-terminal cap 1 structures (m7GpppNm) on eukaryotic mRNAs, was inserted into a bovine papilloma virus vector under the control of a mouse metallothionein I (MT-I) promoter. After transfection of this vector into mouse NIH 3T3 cells, a cell line, cPB2, was obtained that produces PB2-specific mRNA and authentic PB2 protein. Induction of the MT-I promoter with CdCl2 causes about a 10-fold increase in PB2 mRNA and protein levels. The expressed PB2 protein is functional, as it relieves the block in viral mRNA synthesis exhibited by a temperature-sensitive viral mutant containing a cap-binding defect in the PB2 protein. This demonstrates complementation of a function of a negative-strand RNA virus by a gene product expressed in a cell line from recombinant DNA.  相似文献   

7.
目的探索无细胞麦芽体外蛋白合成系统重组表达恶性疟原虫蛋白可行性,并检测用重组蛋白制备的免疫血清对原虫蛋白的特异性反应。方法将目的蛋白PfRON2的部分片断克隆连接到重组表达载体后,用无细胞麦芽体外蛋白合成系统进行重组表达并纯化,用纯化的重组蛋白免疫小鼠制备免疫血清,并用免疫斑点实验(Western blot)和免疫荧光抗体实验(IFA)检测该血清对恶性疟蛋白的特异性反应。结果成功克隆的重组质粒能在无细胞麦芽体外蛋白合成系统中生成大小相符的GST融合蛋白,并能较好地纯化。免疫斑点实验中,用该重组蛋白制备的免疫血清能检测到重组蛋白和恶性疟目标蛋白,免疫荧光抗体实验显示该免疫血清能成功地标记恶性疟目标蛋白所在部位。结论无细胞麦芽体外蛋白合成系统可应用于恶性疟原虫蛋白的重组表达,获得的免疫血清能特异性识别疟原虫蛋白。  相似文献   

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9.
The human alpha 1-globin gene was fused downstream of two erythroid-specific DNase I super-hypersensitive sites that are normally located upstream of the human beta-globin locus. This construct was injected into fertilized mouse eggs, and expression was analyzed in 16-day fetal livers and brains. All 11 fetuses that contained intact copies of the transgene expressed correctly initiated human alpha-globin mRNA in the erythroid fetal liver but not in brain. Levels of expression ranged from 4% to 337% of endogenous mouse beta-globin mRNA. A human alpha-globin construct that did not contain super-hypersensitive sites was not expressed. These results demonstrate that human beta-globin locus activation sequences can stimulate high levels of human alpha-globin gene expression in erythroid tissue of transgenic mice. The results also provide a foundation for experiments designed to coexpress human alpha- and beta-globin genes in transgenic mice and suggest a feasible approach for production of a mouse model for human sickle cell disease.  相似文献   

10.
The whey acidic protein (WAP) is a major milk protein in mice, rats, and rabbits but has not been found in milk of livestock including swine. To determine whether mammary gland regulatory elements from the WAP gene function across species boundaries and whether it is possible to qualitatively alter milk protein composition, we introduced the mouse WAP gene into the genome of swine. Three lines of transgenic swine were analyzed, and mouse WAP was detected in milk from all lactating females at concentrations of about 1 g/liter; these levels are similar to those found in mouse milk. Expression of the corresponding RNA was specific to the mammary gland. Our results suggest that the molecular basis of mammary-specific gene expression is conserved between swine and mouse. In addition the WAP gene must share, with other milk protein genes, elements that target gene expression to the mammary gland. Mouse WAP accounted for about 3% of the total milk proteins in transgenic pigs, thus demonstrating that it is possible to produce high levels of a foreign protein in milk of farm animals. that it is possible to produce high levels of a foreign protein in  相似文献   

11.
We report that promoters for two murine acute-phase protein (APP) genes, complement factor 3 (C3) and serum amyloid A3 (SAA3), can increase recombinant protein expression in response to inflammatory stimuli in vivo. To deliver APP promoter-luciferase reporter gene constructs to the liver, where most endogenous APP synthesis occurs, we introduced them into a nonreplicating adenovirus vector and injected the purified viruses intravenously into mice. When compared with the low levels of basal luciferase expression observed prior to inflammatory challenge, markedly increased expression from the C3 promoter was detected in liver in response to both lipopolysaccharide (LPS) and turpentine, and lower-level inducible expression was also found in lung. In contrast, expression from the SAA3 promoter was found only in liver and was much more responsive to LPS than to turpentine. After LPS challenge, hepatic luciferase expression increased rapidly and in proportion to the LPS dose. Use of cytokine-inducible promoters in gene transfer vectors may make it possible to produce antiinflammatory proteins in vivo in direct relationship to the intensity and duration of an individual's inflammatory response. By providing endogenously controlled production of recombinant antiinflammatory proteins, this approach might limit the severity of the inflammatory response without interfering with the beneficial components of host defense and immunity.  相似文献   

12.
The expression of hepatitis B viral antigens was quantified in liver tissue from four transplant recipients with fibrosing cholestatic hepatitis (FCH) and compared with five other transplant recipients who did not develop this syndrome and 30 patients with chronic hepatitis B virus (HBV) infection. As measured by radioimmunoassays, the liver tissue from patients with FCH had significantly greater amounts of both hepatitis B surface antigen (HBsAg) and nucleocapsid antigens than to transplant patients without this syndrome (P less than 0.01) or patients with chronic HBV infection (P less than 0.001). Intrahepatic expression of pre-S1/pre-S2 in FCH was also extensive with a distribution parallel to that of HBsAg. High-level expression of intrahepatic HBsAg and hepatitis B core antigen in the explanted liver was associated with subsequent development of FCH in the liver graft, suggesting that viral/host factors may also be important. This pattern of intrahepatic hepatitis viral antigen expression, by analogy with Chisari's transgenic mice model and Roingeard's HBV-transfected HepG2 cell model, may be the cause of direct hepatocytopathic injury in this condition.  相似文献   

13.
目的在大肠埃希菌中高效表达结核杆菌phoS2,通过免疫印迹反应初步鉴定重组蛋白的抗原性和特异性。方法采用DNA重组技术构建结核分枝杆菌phoS2抗原表达载体,用双酶切和PCR等方法鉴定转化子,重组质粒转化大肠埃希菌,诱导表达phoS2;用SDS-PAGE初步鉴定其表达量;将表达产物进行纯化;重组蛋白用Western blot分析其抗原性和特异性。结果phoS2基因在大肠埃希菌中得到高效表达,表达量占全菌蛋白的40%以上;重组蛋白与结核病患者血清标本呈强阳性反应,与健康人血清标本呈阴性反应。结论重组phoS2蛋白在大肠埃希菌中主要以包涵体形式表达,有很好的抗原特异性和免疫原性,对结核病诊断有潜在的应用价值。  相似文献   

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15.
The subtilisin-related proprotein convertase furin is expressed in various mammalian tissues. Expecting that COS-1 cells have a furin-like endoprotease, we constructed a fusion expression vector for production of a recombinant foreign protein having no signal peptide or a protein in truncated form into secreted mature protein. A cDNA fragment encoding N-terminal procalcitonin (pro-CT) of human calcitonin precursor was inserted into the mammalian expression vector pME18S. We used PCR techniques to generate four kinds of cDNAs encoding the C terminus of the pro-CT with Arg residues at P4 (Arg-Xaa-Lys-Arg), P6 (Arg-Xaa-Xaa-Xaa-Lys-Arg), or both (Arg-Xaa-Arg-Xaa-Lys-Arg), in addition to the Lys-Arg motif at the cleavage site, in order to determine the conditions for efficient processing in nonendocrine cells, such as COS-1 cells. The cDNA coding for the Fc fragment of human immunoglobulin G1 was fused in-frame to the cDNA encoding pro-CT at its C terminus. Upon transfection of the chimeric plasmids into COS-1 cells, almost all of the fusion protein with the Arg residues at both P4 and P6 were processed into secreted Fc product, even without cotransfection of furin. These results indicate that COS-1 cells have a furin-like endoprotease and suggest that pro-CT, with the Arg residues at both P4 and P6, can be used as a carrier peptide for expression of a foreign protein having no signal peptide or a protein in truncated form in COS-1 cells.  相似文献   

16.
Helper component (HC) is a virus-encoded nonstructural protein that is required for transmission of potyviruses by their aphid vectors. As a prelude to studies on the molecular basis of HC activity, a cDNA clone (pPB-3) was constructed that contained the first three cistrons (34 kDa-HC-42 kDa) of the RNA genome of the potyvirus tobacco vein mottling virus, the first six nucleotides of the adjacent cylindrical inclusion body protein cistron, and a synthetic translation termination codon. This construction was introduced into tobacco cells via a Ti plasmid-based vector. Northern blot analysis of transgenic plants demonstrated the presence of an RNA of the size expected from the construction of pPB-3, and Western blot analysis revealed the presence of a protein that comigrated with authentic HC, indicating that the proteolytic activity necessary to produce mature-sized HC was encoded by pPB-3. The HC produced in the transgenic plants was demonstrated to be active in a virus transmission bioassay with aphids.  相似文献   

17.
目的 目的 确定蛔虫基因工程疫苗候选基因。方法 方法 连接经BamH I和EcoR I酶切的pMD18?T?ALAg和pET?28a(+)质粒的纯化回收产物, 将连接产物pET?28a(+)?ALAg表达载体转化表达菌株BL21(DE3)进行诱导表达, 并纯化重组蛋白 (rALAg)。30只小鼠分成免疫组、 佐剂组和对照组, 每组10只, 各组分别接种重组蛋白与弗氏完全佐剂(FCA)混合物、 FCA以及磷酸盐缓冲液 (PBS) 后, 采用蛔虫感染性虫卵进行攻击(3 600个/只), 观察各组小鼠体内虫体数, 并采用间接ELISA法检测小鼠血清中抗体IgG。结果 结果 rALAg能被兔抗蛔虫阳性血清所识别。免疫组小鼠的肝脏和肺脏中的蛔虫幼虫数量(25.30±4.55) 比对照组 (57.60±5.76) 减少了69.26%, 与对照组和佐剂组比较差异有统计学意义(P < 0.01); 免疫组IgG抗体水平检测血清吸光度值A450 (0.858±0.003) 与对照组 (0.149±0.004)、 佐剂组比较 (0.134±0.004) 差异有统计学意义(P < 0.01)。结论 结论 ALAg基因可作为蛔虫基因工程疫苗的候选基因。  相似文献   

18.
Efficient myocardial gene transfer in the intact adult heart is difficult using conventional transfer vectors. Since coxsackievirus B3 (CVB3) is cardiotropic, it may be possible to exploit its cardiotropic characteristics to design a vector for gene transfer to the intact heart. We generated a recombinant CVB3 cDNA by inserting a green fluorescent protein (GFP) gene immediately upstream from the VP0 capsid protein of CVB3. The infectious virus (rCVB3-GFP) was recovered from the supernatants of the transfected Cos-7 cells, and was grown in HeLa cells to titers of 10(11) pfu/ml. In the rCVB3-GFP infected HeLa cells and neonatal rat cardiac myocytes, GFP protein expression was documented by immunoblot and by fluorescent microscopy. GFP expression was maintained after five passages in HeLa cells. To test in vivo expression of GFP, we infected 8-week-old inbred female Balb/C mice with 10(6) pfu of rCVB3-GFP, intraperitoneally. GFP was present in up to 30% of cardiac myocytes over the 8 weeks post infection (p.i.) and it was co-localized with CVB3 infection. Surprisingly, in spite of detection of GFP up to at least 8 weeks after infection, there was no mortality in the mice. It is possible to express exogenous proteins in the intact heart after an intraperitoneal (i.p.) injection of recombinant coxsackievirus. The duration of expression persisted for at least 8 weeks with little immune response nor mortality. These results demonstrated that the cardiac tropism of CVB3 could be used to design vectors for efficient gene expression in the intact heart.  相似文献   

19.
DNA-coated gold particles were introduced into meristems of immature soybean seeds using electric discharge particle acceleration to produce transgenic fertile soybean plants. The lineages of integrated foreign DNA in two independently transformed plants were followed in the first (R1) and second (R2) generation of self-pollinated progeny. One plant (4615) was transformed with the Escherichia coli genes for β-glucuronidase and neomycin phosphotransferase II; the other (3993) was transformed only with the gene for β-glucuronidase. Segregation ratios for the introduced gene(s) were approximately 3:1 for plant 4615 and 1:1 for plant 3993 in the R1 generation. DNA analysis showed 100% concordance between presence of the foreign gene sequences and enzyme activity. Moreover, all copies of the foreign genes are inherited as a unit in each plant. Plant 3993 segregated in a 1:1 ratio in the R2 generation. R1 plants derived from plant 4615, which expressed both genes, gave either 100% or 3:1 expression of both genes in the R2 generation, demonstrating recovery of both homozygous and heterozygous R1 plants. Our results show that foreign DNA introduced into soybean plants using electric discharge particle acceleration can be inherited in a Mendelian manner. Results also demonstrate cotransformation of tandem markers and show that both markers are inherited as closely linked genes in subsequent generations. These results indicate that whole plants can be derived from single transformed cells by a de novo organogenic pathway.  相似文献   

20.
目的构建小鼠白介素-10(murineinterleukin-10,mIL-10)的真核表达载体,并研究其在293T细胞中的表达。方法 RT-PCR扩增小鼠脾脏IL-10基因后,克隆到真核表达载体pcDNA3.0上,酶切和测序鉴定重组质粒的大小、序列。采用脂质体转染法将重组质粒pcDNA3.0-mIL-10瞬时转染293T细胞,用Westernblot法检测IL-10表达。结果重组质粒pcDNA3.0-mIL-10构建成功,而且转染了293T细胞中提取的蛋白可检测到活性蛋白。结论经酶切和测序鉴定重组质粒pcDNA3.0-mIL-10构建成功,并在293T细胞中成功表达活性蛋白,为进一步研究其生物学功能奠定了基础。  相似文献   

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