首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
将禽流感病毒M2基因克隆于真核表达质粒pIRES-EGFP中,使其位于pCMV启动子的调控下,并与绿色荧光蛋白基因(EGFP)串联后,将上述串联基因插入到含MDV CVI988的非必需区US基因的重组质粒pUS2中,构建带标记的重组质粒,然后将此重组质粒转染感染了MDV CVI988的鸡胚成纤维细胞,利用同源重组的方法,筛选了表达禽流感病毒M2基因的重组病毒MDV1。经PCR、Dot-blotting,Western-blotting等实验的结果表明,禽流感病毒M2基因的确插入到MDV1(CVI988)基因组中并获得表达。重组MDV1免疫1日龄SPF鸡21天后,用ELISA可检测到M2蛋白的特异性抗体。接种了重组病毒rMDV的鸡体内针对H9N2疫苗血凝素的抗体滴度(p<0.05)明显提高,以禽流感病毒AIV A/Chicken/Guangdong/00(H9N2)攻毒后进行病毒重分离试验的结果发现,重组病毒能有效地降低病毒的排出量(p<0.01),说明该重组病毒可以用于防制禽流感的免疫。  相似文献   

2.
A plant based high fidelity vaccine production system is being developed with emphasis on producing antigens capable of being orally delivered in multivalent or subunit plant packets. Plant-based edible vaccines may provide an attractive, safe and inexpensive alternative to conventional vaccine production. Edible plant tissues are not normally antigenic in nature. However, foreign antigens from common infectious organisms like hepatitis-B virus (HBV) can be produced along with naturally occurring storage proteins in DNA-transformed plants. Upon administration via the oral route, these transgenic plant tissues may mobilize the protective humoral and mucosal immune responses to challenge the natural infectious agent. When tobacco, carrot and rice plants were transformed with the truncated version of the HBV nucleocapsid gene expression construct, non-infective hepatitis B viral core particles were observed via electron microscopy. A second plant codon-optimised HBV expression construct was designed that included the extensin signal sequence for augmented HBV particle accumulation. Upon transformation of tobacco plants with the codon-optimised construct, over 4 times more transgenic plants with high levels of expression of the HBV nucleocapsid protein were generated in comparison with a similar vector containing the unmodified wild-type HBV gene codon sequence. Further analysis via Western blotting confirmed the presence of the viral antigen in the total protein extracts from transgenic tobacco leaves and seeds. Electron microscopy showed that the expressed protein self-assembled into viral-like particles of 25–30 nm in diameter. To develop an edible subunit vaccine in plant seeds, a third plant transformation construct was used for the synthesis of the human cytomegalovirus glycoprotein B (HCMV gB) subunit. The gB protein derived from tobacco seeds retained critical structural features including epitopes for neutralizing antibodies and was targeted to the protein storage vesicles of tobacco seed endosperm. Two different strains of mice were orally immunized with tobacco seeds containing low concentrations of HCMV gB, with varying dosages, but without adjuvant. No anti-gB response was detected in intestinal or serum samples. However, a systemic immune response to normal tobacco seed proteins was observed in both strains of mice. While higher expression levels of antigens in seeds must be achieved, seeds may provide an effective and immunostimulatory vehicle for delivering edible vaccines to the intestinal mucosa. One of the outstanding challenges includes defining optimum conditions of antigen presentation, dosage and immunization schedules that will induce strong mucosal and/or systemic immune responses in heterogeneous populations. Here we review the different strategies being employed to produce specific oral antigens in plant tissues.  相似文献   

3.
Avian influenza has raised many apprehension in the recent years because of its potential transmitability to humans. With the increasing emergence of drug-resistant avian influenza strains, development of potential vaccines are imperative to manage this disease. Two structural antigens, haemagglutinin and neuraminidase, have been the target candidates for the development of subunit vaccine against influenza. In an effort to develop a faster and economically beneficial vaccine, the neuraminidase gene of a highly pathogenic avian influenza isolate was cloned and expressed in the methylotrophic yeast Pichia pastoris. The recombinant neuraminidase (rNA) antigen was purified, and its bioactivity was analysed. The rNA was found to be functional, as determined by the neuraminidase assay. Four groups of mice were immunized with different concentrations of purified rNA antigen, which were adjuvanted with aluminium hydroxide. The immune response against rNA was analysed by enzyme-linked immunosorbent assay (ELISA) and neuraminidase inhibition assay. The mice groups immunized with 25 μg and 10 μg of antigen had a significant immune response against rNA. This method can be utilized for faster and cost-effective development of vaccines for a circulating and newer strain of avian influenza, and would aid in combating the disease in a pandemic situation, in which production time matters greatly.  相似文献   

4.
An open reading frame representing cDNA from a hemagglutinin (HA) encoding gene of a low pathogenic avian influenza virus (AIV) subtype H10N7 was cloned in the pNMT1-TOPO vector under the control of thiamine response promoter. This construct was designated as pNMT1-HA. The pNMT1-HA construct was transformed into Schizosaccharomyces pombe for expression of HA antigen. The correct expression of recombinant HA protein was confirmed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. The level of expression of recombinant HA protein was approximately 0.2% of total soluble protein. Purified yeast-derived recombinant HA protein showed hemagglutination activity. The 2-D and 3-D scanning images of recombinant HA protein were observed with an atomic force microscope (AFM). The structural integrity of the HA protein under AFM and hemagglutination activity provided support that the recombinant HA protein may be suitable for development of AIV subunit vaccine for mass administration to poultry.  相似文献   

5.
Reducing the cost of vaccine production is a key priority for veterinary research, and the possibility of heterologously expressing antigen in plants provides a particularly attractive means of achieving this. Here, we report the expression of the avian influenza virus haemagglutinin (AIV HA) in tobacco, both as a monomer and as a trimer in its native and its ELPylated form. We firstly presented evidence to produce stabilized trimers of soluble HA in plants. ELPylation of these trimers does not influence the trimerization. Strong expression enhancement in planta caused by ELPylation was demonstrated for trimerized H5‐ELP. ELPylated trimers could be purified by a membrane‐based inverse transition cycling procedure with the potential of successful scale‐up. The trimeric form of AIV HA was found to enhance the HA‐specific immune response compared with the monomeric form. Plant‐derived AIV HA trimers elicited potentially neutralizing antibodies interacting with both homologous virus‐like particles from plants and heterologous inactivated AIV. ELPylation did not influence the functionality and the antigenicity of the stabilized H5 trimers. These data allow further developments including scale‐up of production, purification and virus challenge experiments with the final goal to achieve suitable technologies for efficient avian flu vaccine production.  相似文献   

6.
Domestic poultry serve as intermediates for transmission of influenza A virus from the wild aquatic bird reservoir to humans, resulting in influenza outbreaks in poultry and potential epidemics/pandemics among human beings. To combat emerging avian influenza virus, an inexpensive, heat-stable, and orally administered influenza vaccine would be useful to vaccinate large commercial poultry flocks and even migratory birds. Our hypothesized vaccine is a recombinant attenuated bacterial strain able to mediate production of attenuated influenza virus in vivo to induce protective immunity against influenza. Here we report the feasibility and technical limitations toward such an ideal vaccine based on our exploratory study. Five 8-unit plasmids carrying a chloramphenicol resistance gene or free of an antibiotic resistance marker were constructed. Influenza virus was successfully generated in avian cells transfected by each of the plasmids. The Salmonella carrier was engineered to allow stable maintenance and conditional release of the 8-unit plasmid into the avian cells for recovery of influenza virus. Influenza A virus up to 107 50% tissue culture infective doses (TCID50)/ml were recovered from 11 out of 26 co-cultures of chicken embryonic fibroblasts (CEF) and Madin-Darby canine kidney (MDCK) cells upon infection by the recombinant Salmonella carrying the 8-unit plasmid. Our data prove that a bacterial carrier can mediate generation of influenza virus by delivering its DNA cargoes into permissive host cells. Although we have made progress in developing this Salmonella influenza virus vaccine delivery system, further improvements are necessary to achieve efficient virus production, especially in vivo.  相似文献   

7.
Highly pathogenic avian influenza H5N1 viruses can result in poultry and occasionally in human mortality. A safe and effective H5N1 vaccine is urgently needed to reduce the pandemic potential. Hemagglutinin (HA), a major envelope protein accounting for approximately 80% of spikes in influenza virus, is often used as a major antigen for subunit vaccine development. In this study, we conducted a systematic study of the immune response against influenza virus infection following immunization with recombinant HA proteins expressed in insect (Sf9) cells, insect cells that contain exogenous genes for elaborating N-linked glycans (Mimic) and mammalian cells (CHO). While the antibody titers are higher with the insect cell derived HA proteins, the neutralization and HA inhibition titers are much higher with the mammalian cell produced HA proteins. Recombinant HA proteins containing tri- or tetra-antennary complex, terminally sialylated and asialyated-galactose type N-glycans induced better protective immunity in mice to lethal challenge. The results are highly relevant to issues that should be considered in the production of fragment vaccines.  相似文献   

8.
【目的】由于H7N9禽流感病毒能够感染鸡,并且已经变异成了高致病性毒株,因此,鸡群中H7N9禽流感疫苗的免疫是一个趋势,而鸡群免疫后抗体检测方法的建立也十分必要。本研究旨在建立一种灵敏、高效、高通量的鸡群H7N9亚型禽流感病毒抗体间接酶联免疫吸附试验(ELISA)检测方法。【方法】通过昆虫杆状病毒表达系统分别表达属于W1、W2-A和W2-B分支H7N9流感病毒的3种野生型血凝素(HA)蛋白,以及跨膜区(TM)置换为H3 HA TM的W2-B分支HA蛋白(H7-53TM)。4种HA蛋白经过离子交换层析纯化后作为抗原,通过ELISA检测H7N9禽流感病毒抗体。【结果】ELISA特异性、敏感性和重复性试验结果显示,跨膜区置换主要影响HA蛋白ELISA检测的重复性,以H7-53TM为抗原的ELISA方法具有较好的重复性,其批内和批间变异系数小于10%,然而3种野生型HA蛋白与部分血清反应批内和批间变异系数大于10%,重复性较差,因此选择H7-53TM蛋白作为ELISA包被抗原。通过受试者工作特征曲线(ROC曲线)分析,以H7-53TM为抗原的ELISA能够精准地区分H7N9亚型流感病毒抗体阳性和阴性血清。通过相关性分析,该ELISA方法与134份鸡血清HI试验结果具有显著强相关性(r=0.854 6,P0.000 1),并且与3个分支疫苗株免疫血清的HI试验结果也具有显著相关性(r0.5,P0.05)。【结论】跨膜区置换能够提高HA蛋白抗原检测H7N9禽流感病毒抗体的重复性,并应用跨膜区置换的HA蛋白建立了一种能够检测不同分支疫苗株免疫的H7N9亚型禽流感病毒抗体间接ELISA检测方法。  相似文献   

9.
H9亚型禽流感在全球范围内广泛流行,控制其传播需监测H9亚型禽流感病毒的感染情况及疫苗的免疫效果。为了建立便于检测且灵敏特异的H9亚型禽流感抗体间接ELISA方法,本实验利用不同亚型之间变异较大的H9亚型禽流感病毒HA蛋白的头部球状区作为包被抗原,确定了最佳复合封闭液和抗体稀释液,提高了其特异性。结果显示建立的ELISA方法灵敏度高于血凝抑制试验(HI),且与H3N2、H5N2、H7N9亚型流感病毒及新城疫病毒(NDV)、鸡传染性支气管炎病毒(IBV)、鸡传染性法氏囊病毒(IBDV)和产蛋下降综合征病毒(EDSV)的阳性血清均无交叉反应。另外,利用该方法及HI试验对200份临床鸡血清样本进行检测,两种检测方法的符合率达97%,且存在较高的相关性(R2=0.981 1)。  相似文献   

10.
The present Influenza vaccine manufacturing process has posed a clear impediment to initiation of rapid mass vaccination against spreading pandemic influenza. New vaccine strategies are therefore needed that can accelerate the vaccine production. Pichia offers several advantages for rapid and economical bulk production of recombinant proteins and, hence, can be attractive alternative for producing an effective influenza HA based subunit vaccine. The recombinant Pichia harboring the transgene was subjected to fed-batch fermentation at 10 L scale. A simple fermentation and downstream processing strategy is developed for high-yield secretory expression of the recombinant Hemagglutinin protein of pandemic Swine Origin Influenza A virus using Pichia pastoris via fed-batch fermentation. Expression and purification were optimized and the expressed recombinant Hemagglutinin protein was verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis, Western blot and MALDI-TOF analysis. In this paper, we describe a fed-batch fermentation protocol for the secreted production of Swine Influenza A Hemagglutinin protein in the P. pastoris GS115 strain. We have shown that there is a clear relationship between product yield and specific growth rate. The fed-batch fermentation and downstream processing methods optimized in the present study have immense practical application for high-level production of the recombinant H1N1 HA protein in a cost effective way using P. pastoris.  相似文献   

11.
Conventional influenza vaccines are based on a virus obtained in chicken embryos or its components. The high variability of the surface proteins of influenza virus, hemagglutinin and neuraminidase, requires strain-specific vaccines matching the antigenic specificity of newly emerging virus strains to be developed. A recombinant vaccine based on a highly conservative influenza virus protein M2 fused to a nanosized carrier particle can be an attractive alternative to traditional vaccines. We have constructed a recombinant viral vector based on potato X virus that provides for expression in the Nicotiana benthamiana plants of a hybrid protein M2eHBc consisting of an extracellular domain of influenza virus M2 protein (M2e) fused to hepatitis B core antigen (HBc). This vector was introduced into plant cells by infiltrating leaves with agrobacteria carrying the viral vector. The hybrid protein M2eHBc was synthesized in the infected N. benthamiana plants in an amount reaching 1–2% of the total soluble protein and formed virus-like particles with the M2e peptide presented on the surface. Methods of isolation and purification of M2eHBc particles from plant producers were elaborated. Experiments on mice have shown a high immunogenicity of the plant-produced M2eHBc particles and their protective effect against lethal influenza challenge. The developed transient expression system can be used for production of M2e-based candidate influenza vaccine in plants.  相似文献   

12.
FluBlok, a recombinant trivalent hemagglutinin (rHA) vaccine produced in insect cell culture using the baculovirus expression system, provides an attractive alternative to the current egg-based trivalent inactivated influenza vaccine (TIV). Its manufacturing process presents the possibility for safe and expeditious vaccine production. FluBlok contains three times more HA than TIV and does not contain egg-protein or preservatives. The high purity of the antigen enables administration at higher doses without a significant increase in side-effects in human subjects.The insect cell–baculovirus production technology is particularly suitable for influenza where annual adjustment of the vaccine is required. The baculovirus–insect expression system is generally considered a safe production system, with limited growth potential for adventitious agents. Still regulators question and challenge the safety of this novel cell substrate as FluBlok continues to advance toward product approval. This review provides an overview of cell substrate characterization for expresSF cell line used for the manufacturing of FluBlok.In addition, this review includes an update on the clinical development of FluBlok. The highly purified protein vaccine, administered at three times higher antigen content than TIV, is well tolerated and results in stronger immunogenicity, a long lasting immune response and provides cross-protection against drift influenza viruses.  相似文献   

13.
We previously showed that recombinant extra domain A from fibronectin (EDA) purified from Escherichia coli was able to bind to toll-like receptor 4 (TLR4) and stimulate production of proinflammatory cytokines by dendritic cells. Because EDA could be used as an adjuvant for vaccine development, we aimed to express it from the tobacco plastome, a promising strategy in molecular farming. To optimize the amount of recombinant EDA (rEDA) in tobacco leaves, different downstream sequences were evaluated as potential fusion tags. Plants generated by tobacco plastid transformation accumulated rEDA at levels up to 2% of the total cellular protein (equivalent to approximately 0.3 mg/g fresh weight) when translationally fused to the first 15 amino acids of green fluorescence protein (GFP). The recombinant adjuvant could be purified from tobacco leaves using a simple procedure, involving ammonium sulfate precipitation and anion exchange chromatography. Purified protein was able to induce production of tumour necrosis factor-α (TNF-α) either by bone marrow-derived dendritic cells or THP-1 monocytes. The rEDA produced in tobacco leaves was also able to induce upregulation of CD54 and CD86 maturation markers on dendritic cells, suggesting that the rEDA retains the proinflammatory properties of the EDA produced in E. coli and thus could be used as an adjuvant in vaccination against infectious agents and cancer. Taken together, these results demonstrate that chloroplasts are an attractive production vehicle for the expression of this protein vaccine adjuvant.  相似文献   

14.
For the rapid production of influenza vaccine antigens in unlimited quantities, a transition from conventional egg-based production to cell-based and recombinant systems is required. The need for higher-yield, lower-cost, and faster production processes is critical to provide adequate supplies of influenza vaccine to counter global pandemic threats. In this study, recombinant hemagglutinin proteins of influenza virus were expressed in the microalga Schizochytrium sp., an established, fermentable organism grown in large scale for the manufacture of polyunsaturated fatty acids for animal and human health applications. Schizochytrium was capable of exporting the full-length membrane-bound proteins in a secreted form suitable for vaccine formulation. One recombinant hemagglutinin (rHA) protein derived from A/Puerto Rico/8/34 (H1N1) influenza virus was evaluated as a vaccine in a murine challenge model. Protective immunity from lethal challenge with homologous virus was elicited by a single dose of 1.7, 5 or 15 µg rHA with or without adjuvant at survival rates between 80–100%. Full protection (100%) was established at all dose levels with or without adjuvant when mice were given a second vaccination. These data demonstrate the potential of Schizochytrium sp. as a platform for the production of recombinant antigens useful for vaccination against influenza.  相似文献   

15.
Human influenza viruses are responsible for annual epidemics and occasional pandemics that cause severe illness and mortality in all age groups worldwide. Matrix protein 2 (M2) of influenza A virus is a tetrameric type III membrane protein that functions as a proton-selective channel. The extracellular domain of M2 (M2e) is conserved in human and avian influenza A viruses and is being pursued as a component for a universal influenza A vaccine. To develop a M2e vaccine that is economical and easy to purify, we genetically fused M2e amino acids 2–16 to the N-terminus of pVIII, the major coat protein of filamentous bacteriophage f88. We show that the resulting recombinant f88−M2e2-16 phages are replication competent and display the introduced part of M2e on the phage surface. Immunization of mice with purified f88−M2e2-16 phages in the presence of incomplete Freund’s adjuvant, induced robust M2e-specific serum IgG and protected BALB/c mice against challenge with human and avian influenza A viruses. Thus, replication competent filamentous bacteriophages can be used as efficient and economical carriers to display conserved B cell epitopes of influenza A.  相似文献   

16.
克隆、表达和鉴定禽流感病毒H9N2 HA,NA基因序列,为制备抗体和基因工程疫苗打下基础。在成功克隆禽流感病毒H9N2全长HA、NA基因并测序的基础上,将部分基因序列克隆到表达载体pET32a(+)上,全基因序列克隆到表达载体pGEX4T-1上,构建了重组表达质粒pET32a(+)/HA(截短)、pET32a(+)/NA(截短)、pGEX4T-1/HA、pGEX4T-1/NA,转化大肠杆菌BL21/rosetta,IPTG诱导表达,利用Ni2+亲和层析柱和GSTrap4B亲和层析柱对重组蛋白进行纯化,并用Western Blotting和ELISA方法检测其抗原性。结果重组蛋白在大肠杆菌中可以高效表达,SDS-PAGE显示其相对分子质量与预计大小一致。ELISA和Western Blotting实验证实,重组蛋白具有良好的抗原性。本研究成功克隆和表达了禽流感病毒H9N2 HA、NA基因序列。为禽流感病毒H9N2诊断试剂和疫苗的开发等进一步的研究奠定了基础。  相似文献   

17.
Ge J  Deng G  Wen Z  Tian G  Wang Y  Shi J  Wang X  Li Y  Hu S  Jiang Y  Yang C  Yu K  Bu Z  Chen H 《Journal of virology》2007,81(1):150-158
H5N1 highly pathogenic avian influenza virus (HPAIV) has continued to spread and poses a significant threat to both animal and human health. Current influenza vaccine strategies have limitations that prevent their effective use for widespread inoculation of animals in the field. Vaccine strains of Newcastle disease virus (NDV), however, have been used successfully to easily vaccinate large numbers of animals. In this study, we used reverse genetics to construct a NDV that expressed an H5 subtype avian influenza virus (AIV) hemagglutinin (HA). Both a wild-type and a mutated HA open reading frame (ORF) from the HPAIV wild bird isolate, A/Bar-headed goose/Qinghai/3/2005 (H5N1), were inserted into the intergenic region between the P and M genes of the LaSota NDV vaccine strain. The recombinant viruses stably expressing the wild-type and mutant HA genes were found to be innocuous after intracerebral inoculation of 1-day-old chickens. A single dose of the recombinant viruses in chickens induced both NDV- and AIV H5-specific antibodies and completely protected chickens from challenge with a lethal dose of both velogenic NDV and homologous and heterologous H5N1 HPAIV. In addition, BALB/c mice immunized with the recombinant NDV-based vaccine produced H5 AIV-specific antibodies and were completely protected from homologous and heterologous lethal virus challenge. Our results indicate that recombinant NDV is suitable as a bivalent live attenuated vaccine against both NDV and AIV infection in poultry. The recombinant NDV vaccine may also have potential use in high-risk human individuals to control the pandemic spread of lethal avian influenza.  相似文献   

18.
高致病性H5N1亚型禽流感病毒 (AIV) 严重威胁到人类健康,因此研制高效、安全的禽流感疫苗具有重要意义。以我国分离的首株人H5N1亚型禽流感病毒 (A/Anhui/1/2005) 作为研究对象,PCR扩增基质蛋白2 (M2) 和血凝素 (HA) 基因全长开放阅读框片段,构建共表达H5N1亚型AIV膜蛋白基因 M2和HA的重组质粒pStar-M2/HA。此外,还通过同源重组以293细胞包装出表达M2基因的重组腺病毒Ad-M2以及表达HA基因的重组腺病毒Ad-HA。用间接免疫荧光 (IFA) 方法检测到了各载体上插入基因的表达。按初免-加强程序分别用重组质粒pStar-M2/HA和重组腺病毒Ad-HA+Ad-M2免疫BALB/c小鼠,共免疫4次,每次间隔14 d。第1、3次用DNA疫苗,第2、4次用重组腺病毒载体疫苗,每次免疫前及末次免疫后14 d采集血清用于检测体液免疫应答,末次免疫后14 d采集脾淋巴细胞用于检测细胞免疫应答。血凝抑制 (HI) 实验检测到免疫后小鼠血清中的HI活性。ELISA实验检测到免疫后小鼠血清中抗H5N1亚型流感病毒表面蛋白的IgG抗体。ELISPOT实验检测到免疫后小鼠针对M2蛋白和HA蛋白的特异性细胞免疫应答。流感病毒M2与HA双基因共免疫的研究,为研究开发新型重组流感疫苗奠定了基础。  相似文献   

19.
The conserved M2 protein of influenza A virus is considered as a promising candidate target for a broad-spectrum, recombinant influenza A vaccine. In the present study, the open reading frame (ORF) of avian influenza A/chicken/Iran/101/1998 (H9N2) M2 gene was amplified then cloned in pAED4, prokaryotic expression vector. M2 protein was produced through the expression of this recombinant expression vector (pAED4-M2) in E. coli BL21 (DE3) strain. The expressed M2 protein was analyzed on SDS-PAGE. Western blot assay was used to examine the immunoreaction of the expressed protein using commercial polyclonal anti-M2 antibody. The antigenicity and biological activity of the recombinant protein was also qualitatively detected on infected MDCK cells surface by immunofluorescence assay using rabbit’s immunized antiserum. So, according to the sequence alignment based on the mentioned isolate and the result of immunoassay reaction, it seems recombinant vaccine based on A/chicken/Iran/101/1998(H9N2) M2 protein isolate might cover majority of influenza A virus strains specially H5 and H9 circulating in Iran and neighbor regions significantly.  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号