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1.
简述了DNA疫苗的研究概况,介绍了真核双表达质粒的结构特点及其在基因佐剂和二价DNA疫苗中的应用情况,总结分析了双表达质粒的优点和存在的问题,并对其今后在DNA疫苗中的研究方向和前景进行了展望。  相似文献   

2.
Vaccine approaches against AIDS have focused on inducing cellular immune responses, since many studies revealed the role of T cell responses in the control of human immunodeficiency virus or simian immunodeficiency virus (SIV) infections. The experimental infection of rhesus macaques with SIV or chimeric SHIV is routinely used as a model for AIDS. In such models, DNA immunization is a tool to elicit specific T cell responses and to study their protective efficacy. DNA immunogenicity in primates depends on parameters such as level of antigen expression, choice of the antigen among SIV proteins, use of fusion proteins, route of immunization, and addition of adjuvants. Recent results suggest that priming with DNA and boosting with attenuated recombinant viral vectors, each expressing corresponding SIV antigens, leads to improved specific immunity and, in some cases, affords protection against pathogenic challenge. After preclinical evaluations, DNA has entered clinical trials for a therapeutic or prophylactic gene-based AIDS vaccine.  相似文献   

3.
DNA and recombinant virus vaccines against swine influenza virus (SIV) have been pursued with promising results, but induce poor immunogenicity. This study evaluated the effects of a vaccine regimen in mice including priming with three DNA vaccines expressing soluble HA (sHA), complete HA (tmHA), or sHA fused with three copies murine C3d (sHA-mC3d3) and boosting with recombinant pseudorabies virus expressing HA (rPRV-HA). Immune responses were monitored by ELISA, HI assays, and virus neutralization. Protective efficacy was evaluated by virus isolation from lungs, distribution in tissues, and pathology following challenge with H3N2 SIV. Priming with sHA-mC3d3 and boosting with rPRV-HA induced higher levels of HA-specific antibodies and yielded the most effective protection. This finding implied that priming with a DNA vaccine expressing C3d fused with antigen and boosting with a recombinant vector vaccine is an effective way to induce protective humoral immunity and prevent some infectious diseases.  相似文献   

4.
In this study, we described a rapid and efficient method which integrated the bioinformatic prediction and DNA vaccine technology to identify vaccine candidates against Singapore grouper iridovirus (SGIV). The 162 previously defined open reading frames (ORFs) of SGIV were subjected to extensive sequence similarity searches, as well as motif, cellular location, and domain prediction. Based on our analysis, 13 genes were chosen and cloned into the eukaryotic expression vector pcDNA 3.1. In vitro and in vivo expression of these DNA vaccine constructs was examined in Epinephelus akaara spleen cells (EAGS) and immunized fish by Western blot and RT-PCR analysis, respectively. Three weeks after the second booster, immunized fish were challenged with SGIV and the level of protection and survival was assessed. Fish vaccinated with plasmid DNA encoding viral ORF072, ORF039 and ORF036 (designated as pcDNA-72, pcDNA-39 and pcDNA-36, respectively) exhibited 66.7%, 66.7% and 58.3% relative percent survival rates, respectively, in comparison with the control fish. These three DNA vaccines induced innate immune responses, raising significantly high level of Mx expression relative to the fish vaccinated with the empty plasmid at 3 days post-vaccination. Furthermore, recombinant protein from ORF072 was also used to immunize another set of fish and similar protective effect was obtained. Taken together, our results validated the applicability of bioinformatics in genome mining, resulting in the identification of three protective antigens. The promising results obtained in the present study have prompted further testing to improve the immunogenicity of these potential DNA vaccines.  相似文献   

5.
In this study, experimental canarypox virus (ALVAC) and plasmid DNA recombinant vaccines expressing the gB, gC and gD glycoproteins of EHV-1 were assessed for their ability to protect conventional ponies against a respiratory challenge with EHV-1. In addition, potential means of enhancing serological responses in horses to ALVAC and DNA vaccination were explored. These included co-administration of the antigen with conventional adjuvants, complexation with DMRIE-DOPE and co-expression of the antigen along with equine GM-CSF. Groups of EHV primed ponies were vaccinated twice intra-muscularly with one dose of the appropriate test vaccine at an interval of 5 weeks. Two to 3 weeks after the second vaccination, ponies were infected intra-nasally with the virulent Ab4 strain of EHV-1 after which they were observed clinically and sampled for virological investigations. The results demonstrated that DNA and ALVAC vaccination markedly reduced virus excretion after challenge in terms of duration and magnitude, but failed to protect against cell-associated viremia. Noteworthy was the almost complete absence of virus excretion in the group of ponies vaccinated with ALVAC-EHV in the presence of Carbopol adjuvant or DNA plasmid formulated with aluminium phosphate. The administration of the DNA vaccine in the presence of GM-CSF and formulated in DMRIE-DOPE and of the ALVAC vaccine in the presence of Carbopol adjuvant significantly improved virus neutralising antibody responses to EHV-1. These findings indicate that DNA and ALVAC vaccination is a promising approach for the immunological control of EHV-1 infection, but that more research is needed to identify the immunodominant protective antigens of EHV-1 and their interaction with the equine immune system.  相似文献   

6.
Vaccination is the best approach for controlling the spread of chlamydial infections, in animal and human populations. This review summarises the progress that has been made towards the development of effective vaccines over the last 50 years, and discusses current vaccine strategies. The ultimate goal of vaccine research is to develop efficacious vaccines that induce sterile, long-lasting, heterotypic protective immune responses. To date, the greatest success has been in developing whole organism based killed or live attenuated vaccines against the animal pathogens Chlamydophila abortus and Chlamydophila felis. However, similar approaches have proved unsuccessful in combating human chlamydial infections. More recently, emphasis has been placed on the development of subunit or multicomponent vaccines, as cheaper, safer and more stable alternatives. Central to this is a need to identify candidate vaccine antigens, which is being aided by the sequencing of representative genomes of all of the chlamydial species. In addition, it is necessary to identify suitable adjuvants and develop methods for antigen delivery that are capable of eliciting mucosal and systemic cellular and humoral immune responses. DNA vaccination in particular holds much promise, particularly in terms of safety and stability, although it has so far been less effective in humans and large animals than in mice. Thus, much research still needs to be done to improve the delivery of plasmid DNA, as well as the expression and presentation of antigens to ensure that effective immune responses are induced.  相似文献   

7.
产肠毒素大肠杆菌菌毛的DNA疫苗研究进展   总被引:4,自引:2,他引:2  
王劼 《中国畜牧兽医》2011,38(2):178-180
肠毒素大肠杆菌是导致婴幼儿及旅游者急性腹泻,仔猪腹泻和水肿的主要病原菌之一。菌毛定居因子是该病原菌主要的致病因素。DNA疫苗既能激发机体的细胞免疫,也能诱导特异性的体液免疫。目前用于预防ETEC腹泻的DNA疫苗的研究已取得一定进展,作者从重组质粒的构建、免疫应答、疫苗的接种系统以及基因佐剂4个方面简单的概述了产肠毒素大肠杆菌菌毛的DNA疫苗的研究现状。  相似文献   

8.
Enteric viruses are a major cause of diarrhea in animals and humans. Among them, rotaviruses are one of the most important causes of diarrhea in young animals and human infants. A lack of understanding of mechanisms to induce intestinal immunity and the correlates of protective immunity in neonates has impaired development of safe and effective vaccines against enteric viruses. Studies of candidate vaccines using an adult mouse model of subclinical enteric viral infections often do not predict vaccine efficacy against disease evaluated in neonatal large animals. A series of studies have been conducted using a neonatal gnotobiotic pig model of rotavirus infection and diarrhea to identify correlates of protective immunity and to evaluate traditional and novel vaccine approaches for the induction of mucosal immune responses and protection to enteric viruses. Gnotobiotic pigs recovered from infection with virulent Wa human rotavirus (HRV) (mimic natural infection) had high numbers of intestinal IgA rotavirus-specific primary antibody-secreting cells (ASCs) and memory B-cells (to recall antigen) measured by ELISPOT assay, which correlated with complete protection against rotavirus challenge. Most short-term IgA memory B-cells were resident in the ileum, the major site of rotavirus replication. Spleen, not the bone marrow, was the major resident site for longer-term IgG memory B-cells. Candidate rotavirus vaccines evaluated in pigs for their ability to induce intestinal or systemic ASC and protection against rotavirus infection and diarrhea included attenuated live virus, inactivated virus, and baculovirus-expressed double-layered rotavirus-like particles (2/6-VLPs). In combination with those candidate vaccines, various adjuvants, delivery systems, and immunization routes were tested, including incomplete Freund's adjuvant for i.m. immunization, and a mutant Escherichia coli heat labile enterotoxin R192G (mLT) for i.n. immunization. It was shown that orally administered replicating vaccines were most effective for priming for intestinal IgA ASC and memory B-cell responses, but i.n. administered non-replicating 2/6-VLPs plus mLT were effective as booster vaccines. We conclude that protective immunity depends on the magnitude, location, viral protein-specificity, and isotype of the antibody responses induced by vaccination. Therefore highly effective enteric viral vaccines should: (i) induce sufficient levels of intestinal IgA antibodies; (ii) include viral antigens that induce neutralizing antibodies; and (iii) require the use of effective mucosal adjuvants or antigen delivery systems for non-replicating oral or i.n. vaccines.  相似文献   

9.
疫苗佐剂是使疫苗免疫原性充分发挥的工具,目前动物疫苗佐剂主要以铝盐佐剂和油乳佐剂为主。近年来基因重组疫苗和亚单位疫苗发展迅猛,而这些新型疫苗与传统疫苗相比免疫原性较弱,这就对佐剂提出了更高的要求。当前针对佐剂的研究层出不穷,部分佐剂如MF59、AS01、AS03等已经在人用疫苗中成功应用,但应用于动物疫苗还有技术难题需要攻破。蜂胶佐剂目前在动物疫苗中应用较广,且已经占有了一定的市场份额。为充分比较现有新型疫苗佐剂的优缺点,为后续疫苗佐剂的研究提供参考,就目前广泛研究的新型动物疫苗佐剂进行综述。  相似文献   

10.
基因疫苗在畜禽传染病中的应用及前景   总被引:1,自引:0,他引:1  
介绍了基因疫苗的免疫学特性、增强免疫效力策略以及在畜禽传染病领域中应用的最新动态,展望了其广阔的应用前景,并提出了基因疫苗在应用过程中产生的一系列有待于进一步解决的问题,从而为畜禽传染病的防制提供了新思路和新途径。  相似文献   

11.
禽流感(avian influenza,AI)是由禽流感病毒(AIV)引起的一种禽类烈性综合征,威胁动物和人类公共健康,严重影响中国养禽业发展,接种疫苗一直是控制禽流感病毒传播最有效的手段。基于基因工程技术的不断发展,各种新型疫苗相继研发并投入使用。其中,禽流感DNA疫苗具有安全性高、制备方法简单、易于储藏和运输等优点,受到了广泛关注。常见的禽流感疫苗有HA DNA疫苗、NA DNA疫苗、M DNA疫苗、NP DNA疫苗等。禽流感DNA疫苗是将含有目的基因序列的重组质粒导入动物细胞,诱导动物机体产生体液和细胞免疫应答。为了提高禽流感DNA疫苗的免疫效果,国内外学者通过添加合适的佐剂、将目的基因导入理想质粒载体、对抗原序列优化,增强DNA疫苗的转染效率和基因表达水平,取得了一定的研究成果。自DNA疫苗开始研发至今,H1、H3、H5、H7、H9等众多亚型禽流感DNA疫苗逐步研发。2018年,由中国农业科学院哈尔滨兽医研究所研制的禽流感H5亚型DNA疫苗获得国家一类新兽药证书,是中国首个获得批准的禽流感DNA疫苗,极大地推动了DNA疫苗的发展。文章主要论述了禽流感DNA疫苗的载体构建、免疫机制、佐剂和载体选择以及疫苗研发等方面的研究进展和创新,并对其应用前景进行简要分析,旨在为科研工作者研制新型禽流感疫苗提供新的思路和参考。  相似文献   

12.
This study was conducted to evaluate the immunogenicity of a DNA or RNA vaccines encoding Brucella abortus Cu–Zn superoxide dismutase (SOD) in cattle. Intramuscular injection of plasmid DNA carrying Brucella SOD gene (pcDNA-SOD) into animals elicited both humoral and cellular immune responses. Animals injected with pcDNA-SOD developed SOD IgG antibody with predominance of immunoglobulin G1 (IgG1) isotype over IgG2. In addition, the DNA vaccine elicited a specific T-cell-proliferative response. Furthermore, intraperitoneal injection of cattle with recombinant Semliki Forest virus particles carrying recombinant RNA encoding SOD (SFV-SOD) did not lead to the induction of SOD IgG 1 or 2 antibody, but induced specific T-cell activation. Both vaccines were able to induce a non-significant secretion of gamma interferon and did not induce the secretion of IL-4 or tumor necrosis factor (TNF)-. These results suggest that SOD gene in a genetic vaccine formulation (DNA or RNA) might be of potential us as a vaccine to induce cell-mediated immunity in cattle. To our knowledge, this is the first study to evaluate a genetic vaccine against Brucella in cattle.  相似文献   

13.
Avian influenza (AI) is a kind of avian virulent syndrome caused by avian influenza virus (AIV),which threatens animal and human public health and seriously affects the development of poultry industry in China.Vaccination has always been the most effective means to control the spread of avian influenza virus.Based on the continuous development of genetic engineering technology,a variety of new vaccines have been developed and put into use.Among them,avian influenza DNA vaccine has many advantages,such as high safety,simple preparation,easy storage and transportation.Common HA DNA vaccine,NA DNA vaccine,M DNA vaccine,NP DNA vaccine.Avian influenza DNA vaccine introduces a recombinant plasmid containing the target gene sequence into animal cells to induce a humoral and cellular immune response.In order to improve the immune effect of avian influenza DNA vaccine,researchers at home and abroad have made some achievements in enhancing the transfection efficiency and gene expression level of DNA vaccine by adding appropriate adjuvants,introducing target genes into ideal plasmid vectors and optimizing antigen sequence.Since the development of DNA vaccines,many subtypes of avian influenza DNA vaccines,including H1,H3,H5,H7 and H9 subtypes,have been gradually developed.In 2018,the H5 subtype DNA vaccine developed by Harbin Veterinary Research Institute of The Chinese Academy of Agricultural Sciences obtained the National Class Ⅰ Veterinary Medicine certificate,which is the first DNA vaccine of avian influenza to be approved in China,greatly promoting the development of DNA vaccines.This review mainly discusses the development and innovation of avian influenza DNA vaccine in terms of vector construction,immune mechanism,adjuvant and vector selection,and vaccine research and development,and briefly analyzes its application prospect,in order to provide new ideas and references for researchers to develop new avian influenza vaccine.  相似文献   

14.
Despite the profound developments in recombinant DNA technology there is only one marketed recombinant vaccine (for human viral hepatitis B). The development of others proceeds with great difficulty. Molecular vaccines against veterinary parasites are at the utmost pole of complexity in the spectrum of potential vaccines since these parasites are complex eukaryotic organisms, often dwelling at mucosal surfaces where anamnestic responses are problematic, where the immunogenicity of the parasite components is poorly understood and where the effector mechanisms of immunity are unresolved. Cloning a "protective" gene is only the first step, and perhaps the easiest, in a long process which will be necessary to develop vaccines against parasites. Additional steps will involve comprehensive analyses of the immunological responses to ensure that vaccine antigens contain the correct epitopes to induce appropriate immune effector mechanisms for parasite elimination and immunological memory and that these responses are not genetically restricted. The great expectations for recombinant vaccinia-based vaccines must be modified substantially in the light of recent evidence indicating immunological and other constraints on this approach. The use of anti-idiotype vaccines is an underexplored opportunity for practical parasite vaccines since they have several potentially important advantages. The need to include T cell antigenic peptides in peptide vaccines to extend the range of genetic responsiveness and to induce anamnestic responses is now clear. New algorithms for the prediction of such sites exist and these can be tested experimentally with synthetic peptides. There are no major technical obstacles to the development of vaccines for parasites which cannot be overcome. However substantial long term basic research is needed over a range of disciplines to achieve this worthwhile objective.  相似文献   

15.
细菌性传染病疫苗研究进展   总被引:2,自引:2,他引:0  
通过疫苗免疫来保护易感群体是控制细菌性传染病的一个重要环节,细菌减毒活疫苗减少了疫苗的副反应,同时还考虑到接种疫苗群体的营养和健康状况,能有效侵入和持续刺激机体产生初次免疫应答和再次免疫应答。重组减毒细菌具有能够在体内稳定表达保护性抗原的能力,将一段基因插入到染色体中可提高其稳定性,但一般抗原表达水平较低,不能刺激机体产生强有力的免疫应答,而使用高拷贝数的质粒载体后,选择标记基因的表达水平将远远超过载体维持的需要,增加了重组疫苗中的能量消耗,过度表达的基因产物进一步致弱了疫苗。同时宿主-载体的重组应使外源抗原产生的免疫应答最大化,细菌载体抗原产生的完全免疫应答最小化。  相似文献   

16.
Fang R  Feng H  Hu M  Khan MK  Wang L  Zhou Y  Zhao J 《Veterinary parasitology》2012,187(1-2):140-146
The aim of this study was to evaluate the immune responses of a SAG1 and MIC3 vaccine cocktail in BALB/c mice. Ninety-six BALB/c mice were randomly divided into eight groups, including three plasmid DNA vaccine groups (pcDNA-MIC3, pcDNA-SAG1, pcDNA-MIC3+pcDNA-SAG1), three recombinant pseudotype baculovirus vaccine groups (BV-G-MIC3, BV-G-SAG1, BV-G-SAG1+BV-G-MIC3) and two control groups (PBS and BV-G-EGFP). All groups were immunized intramuscularly twice at three-week intervals. The production of anti-Toxoplasma gondii lysate antigen (TLA) antibodies, lymphoproliferation, levels of IFN-γ, IL-4 and IL-10 and the survival time were monitored after vaccination. The results showed that immunization of BALB/c mice with MIC3 and SAG1 vaccines stimulated both the cellular and humoral immune responses with the production of anti-T. gondii TLA antibodies. The vaccine cocktails of pcDNA-MIC3+pcDNA-SAG1 or BV-G-SAG1+BV-G-MIC3 induced significantly higher immunogenicity than a single-gene vaccine (P<0.05). Splenocytes from the immunized mice significantly proliferated in response to the TLA and released interferon (IFN)-γ (P<0.05). However, the levels of IL-4 and IL-10 in the sera of the immunized mice were not significantly different from those of the controls (P>0.05). Immunization with the vaccine cocktail (BV-G-SAG1+BV-G-MIC3) in mice significantly prolonged survival (50%; P<0.05) against a lethal challenge of T. gondii (RH tachyzoites), while all mice in the other immunized groups and control groups died within 20 and 4 days post-infection, respectively. Furthermore, the recombinant pseudotype baculovirus vaccines induced better immunogenicity than the plasmid DNA vaccines (P<0.05). These results suggest that an excellent vector-mediated vaccine cocktail strategy might be used to develop a new generation of vaccines against T. gondii infection.  相似文献   

17.
Vaccination is a most cost-effective way of controlling infectious diseases in fish. However, some vaccination techniques when applied to hatchery conditions are not as effective as we expect them to be. Modern molecular biology techniques offer a number of opportunities for improving existing bacterial or viral vaccines or creating new ones. One of the most promising trends in vaccinology is development of DNA vaccination. DNA vaccines are based on the gene encoding specific antigen, which is expressed in vaccinated organism and induces the host immune system. DNA vaccines, compared to conventional vaccines, have many advantages including ability to trigger wider immune response, bigger stability and possibility of large-scale production. To date, there are several reports indicating effectiveness of DNA vaccines used against fish pathogens.  相似文献   

18.
Inoculation of plasmid DNA, encoding an immunogenic protein gene of an infectious agent, stands out as a novel approach for developing new generation vaccines for prevention of infectious diseases of animals. The potential of DNA vaccines to act in presence of maternal antibodies, its stability and cost effectiveness and the non-requirement of cold chain have heightened the prospects. Even though great strides have been made in nucleic acid vaccination, still there are many areas that need further research for its wholesome practical implementation. Major areas of concern are vaccine delivery, designing of suitable vectors and cytotoxic T cell responses. Also, the induction of immune responses by DNA vaccines is inconclusive due to the lack of knowledge regarding the concentration of the protein expressed in vivo. Alternative delivery systems having higher transfection efficiency and the use of cytokines, as immunomodulators, needs to be further explored. Recently, efforts are being made to modulate and prolong the active life of dendritic cells, in order to make antigen presentation a more efficacious one. For combating diseases like acquired immunodeficiency syndrome (AIDS), influenza, malaria and tuberculosis in humans; and foot and mouth disease, Aujesky’s disease, swine fever, rabies, canine distemper and brucellosis in animals, DNA vaccine clinical trials are underway. This review highlights the salient features of DNA vaccines, and measures to enhance their efficacy so as to devise an effective and novel vaccination strategy against animal diseases.  相似文献   

19.
为了提高猪繁殖与呼吸综合征病毒(PRRSV)ORF5基因DNA疫苗的免疫效力,将通用型辅助性T淋巴细胞表位(PADRE)插入ORF5的中和表位和覆盖表位间,获得修饰后的ORF5基因ORF5M。在此基础上,进一步构建了ORF5M的真核表达质粒pCl-52M。间接免疫荧光证实体外表达后,免疫BALB/c小鼠,检测免疫后的ELISA抗体和中和抗体,并与未经修饰的ORF5基因真核表达质粒pCl-52进行比较。结果表明,修饰后的DNA疫苗pCl-52M诱导的ELISA抗体和中和抗体均明显优于未经修饰的DNA疫苗pCl-52,是一种具有良好开发前景的PRRS新型疫苗。  相似文献   

20.
国外疫苗佐剂的评价   总被引:2,自引:0,他引:2  
各种疫苗在疫病的防治中起着非常重要的作用,佐剂包括铝胶、矿物油、灭活细菌和化学合成物质等,其研究已逐渐成为国际生物制品行业的热点.本文综述了国外人医和兽医中一些著名的佐剂及其安全性、毒理试验和作用机理,同时对我国兽用疫苗佐剂的发展前景作了展望.  相似文献   

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