动物寄生虫口服疫苗研究进展

寄生虫病严重影响全球人类、动物的健康安全，所带来的经济损失巨大。因此，有必要研制针对寄生虫病的疫苗，以阻断寄生虫病在动物与动物、动物与人类之间的传播。寄生虫存在多种免疫逃避机制，已开发的亚单位疫苗、减毒活疫苗、灭活疫苗均未达到理想的预防效果，且商品化疫苗多为针剂疫苗，普通针剂疫苗操作繁琐、运输储藏要求高且易使动物发生应激，直接影响经济成本，因此在实际生产当中需更多操作简单、便于储存、免疫成本更低的新型疫苗，以有效防控寄生虫病。诸多研究表明口服疫苗操作方便，只需通过口服方式投喂且宿主获得的抗体效价水平较高，有望成为预防寄生虫病的有效手段。口服疫苗是一种新型疫苗，依靠宿主的黏膜免疫系统来产生作用，即通过机体黏膜表面接种便可同时诱导机体产生持久的黏膜免疫、体液免疫和细胞免疫，为宿主提供高效的免疫保护。与传统疫苗相比，口服疫苗最显著的优点就是便于接种且应激小，还能形成强大的黏膜免疫屏障。但胃肠道的环境及易形成免疫耐受等因素也为口服疫苗的开发带来很大的挑战。笔者就黏膜免疫系统与口服疫苗作用机理、近几年寄生虫口服疫苗的研究进展及优点与挑战进行综述，以期为寄生虫口服疫苗的开发提供理论依据。     

IBV肾型地方分离株弱毒疫苗与同类冻干疫苗的免疫效力试验比较

本试验对人工致弱IBV肾型地方分离株(SF株)与相应进口弱毒疫苗和国产弱毒疫苗进行了免疫效力比较试验。结果表明SF株免疫后产生抗体的时间和抗体效价高低与其他疫苗相当甚至略高,对攻毒鸡的保护率均为100%。剖检实验鸡,采集肾脏样本做肾脏组织切片,观察发现接种致弱的SF株疫苗后,引起的肾脏组织病理变化比选用的2种国产疫苗病理变化轻微,而与进口疫苗引起的病理变化程度相当,属可逆性病变。     

Humoral antibody responses to different H5N1 and H5N2 vaccination regimes: implications for the development of autogenously based vaccines

Whereas H5N1 vaccine and several H5N2 vaccines are commercially available and are used to control H5N1 outbreaks in some endemic countries, infections hit many vaccinated flocks. The following study was conducted to compare the efficacy of such vaccines and to assess their potential induction of antibodies against the haemagglutinin of local H5N1 isolate after single vaccination. The possible beneficiary effect of booster dose at different intervals was screened for both H5N1 vaccine as well as a selected H5N2 candidate. Differences in the serological immune response among native and cross breeds were also screened. No significant variations were detected between available commercial H5N1 and H5N2 vaccines after single vaccination. Two vaccination shots using H5N1 but not H5N2 vaccine were found to be superior to a single vaccination scheme, where chicks developed more conceivable antibody titers than in single vaccination program. There was considerable variation among chicken lines in the immune response to H5N1 vaccine: native breeds possessed the highest antibody titers as compared to other breeds.     

鱼用疫苗研究进展

鱼用疫苗的种类繁多,除传统疫苗之外,新型疫苗包括合成肽疫苗、DNA疫苗、活载体疫苗、基因缺失疫苗等.一些与鱼用疫苗相关的领域如免疫佐剂、接种方法的研究也逐渐深入.本文对以上研究进展进行了概述,为我国鱼用疫苗的进一步研究和发展提供一些依据.     

寄生虫DNA疫苗研究进展

寄生虫病带来了相当大的社会经济影响,人畜共患寄生虫给人们带来巨大的疾病负担,并给养殖业造成严重的经济损失。因此,寄生虫病的防治是人们迫切需要研究的课题。寄生虫存在很多形式的免疫逃避机制,灭活疫苗、减毒活疫苗、亚单位疫苗等未达到理想的预防寄生虫病的效果,很多研究表明DNA疫苗有望成为预防和治疗寄生虫病的有效方法。DNA疫苗是一种新型疫苗,可同时诱导机体产生持久的体液免疫和细胞免疫,通过在宿主内表达外源蛋白来提供保护性免疫。DNA疫苗与其他亚单位疫苗不同的是,免疫原由摄取抗原编码DNA的细胞在宿主内合成。体内蛋白质的合成也能进行抗原加工、修饰并递呈到宿主的免疫系统中,类似于自然感染的方式。笔者就DNA疫苗免疫机制、设计原则、免疫途径、优缺点及近几年寄生虫DNA疫苗的研究进展进行综述,以期为寄生虫DNA疫苗的开发提供理论参考。     

禽类DNA疫苗研究进展

新型疫苗的研究对于禽类传染病的防制意义重大。传统疫苗是基于抗原刺激机体产生特异性抗体的原理,它们大多数激发机体的体液免疫,很难启动细胞免疫。脱氧核糖核酸(DNA)疫苗作为第3代疫苗,具备传统疫苗和其它基因工程苗不可比拟的优点,能够诱导全方位的免疫反应且使用更安全更方便,DNA疫苗是将外源基因与真核质粒重组后直接导入细胞内,使外源基因在宿主细胞内表达合成保护性抗原蛋白。这是模拟病毒自然感染提呈过程,既能产生细胞免疫,又能产生体液免疫。文章对DNA疫苗在禽类应用的可行性和应用研究新进展作了综述。     

The application of nucleic acid vaccines in veterinary medicine

Nucleic acid immunisation entails the delivery of DNA (or RNA) encoding a vaccine antigen to the recipient. The DNA is taken up by host cells and transcribed to mRNA, from which the vaccine proteins are then translated. The expressed proteins are recognised as foreign by the host immune system and elicit an immune response, which may have both cell-mediated and humoral components. DNA vaccines offer a number of advantages over conventional vaccines, including ease of production, stability and cost. They also allow the production of vaccines against organisms which are difficult or dangerous to culture in the laboratory. This review describes the principles of DNA vaccination and the application of DNA vaccines to veterinary species. Although a great deal of developmental work is required before the technology can give rise to commercial vaccines in domestic animals, there is ongoing research in many fields and it is expected that a number of exciting developments will arise in the next decade.     

Duration of immunity induced by companion animal vaccines

Concerns about possible adverse effects from annual vaccination have prompted the reanalysis of vaccine protocols for cats and dogs. In the last decade, several veterinary advisory groups have published protocols that recommend extended revaccination intervals for certain 'core' vaccines. In addition, practicing veterinarians have been asked to consider vaccination as an individualized medical procedure, based on an analysis of risks and benefits for each vaccine in an individual animal. The calls for extended revaccination intervals prompted considerable debate in USA and internationally. Areas of concern include the amount of evidence to support prolonged immunity from various vaccines, the risk of poor responses in individual animals and the possible effects on population immunity. This review examines how the duration of immunity (DOI) to a vaccine is established in animals and humans. It reviews factors that can affect the DOI in an individual animal, including the types of immune defenses stimulated by the pathogen, and the vaccine, host factors such as age and the level of exposure to the pathogen. In addition, it examines DOI studies that were published for canine and feline core vaccines.     

New generation vaccines and delivery systems for control of bovine tuberculosis in cattle and wildlife

Advances in the understanding of protective immune responses to tuberculosis are providing opportunities for the rational development of improved vaccines for bovine tuberculosis. Protection requires activation of macrophages through stimulation of a Th 1 type immune response. Ideally, a vaccine for cattle should induce protection without causing animals to react in a tuberculin test when exposed to Mycobacterium bovis. A number of new tuberculosis vaccines including attenuated M. bovis strains, killed mycobacteria, protein and DNA vaccines have been developed and many of these are being assessed in cattle. The requirements for a tuberculosis vaccine for wildlife differ from those for cattle. The major goal of a wildlife vaccine is to prevent the transmission of M. bovis to cattle and other wildlife. Although there are a number of technical problems associated with the development of a vaccine delivery system for wildlife, attenuated M. bovis vaccines administered via oral baits or aerosol spray to possums have already been shown to reduce the severity of a subsequent M. bovis infection.     

鸡传染性法氏囊病新型疫苗的研究进展

鸡传染性法氏囊病(IBD)是由鸡传染性法氏囊病病毒(IBDV)引起的雏鸡的一种高度接触性传染病,自1962年报道以来,世界上主要养禽国家和地区均有流行,给养禽业带来严重经济损失。目前,IBD防控的主要方法是采用疫苗接种,使易感雏鸡获得主动或被动免疫保护,因此疫苗的质量对临床上IBD的防控起着至关重要的作用。虽然各国均有较好的商品化疫苗,但随着IBDV毒株的不断变异,商品化疫苗的抗原性与流行毒株不能完全匹配,临床上免疫失败时有发生,因此迫切需要研发与临床流行毒株相匹配的新型疫苗用于IBD的防控。对近期IBD的基因缺失苗、亚单位疫苗、DNA疫苗以及活载体疫苗等新型疫苗的研究进展进行概述,以此为IBD新型疫苗的研究提供参考。     

猪繁殖与呼吸综合征疫苗佐剂研究进展

疫苗免疫是预防和控制传染病的主要措施,但对于猪繁殖与呼吸综合征,疫苗免疫存在免疫效率低与安全性差的问题,效果并不理想。因此,如何在安全剂量下提高动物机体的免疫力,成为疫苗研究的热点之一。试验证明细胞因子、化学试剂和微生物产物等几种免疫佐剂可以增强猪繁殖与呼吸综合征疫苗的免疫效果。在研究的9个疫苗佐剂中,IL-2、IL-12、IFN-α、poly IC和poly ICLC、CpG ODN等能增强猪繁殖与呼吸综合征疫苗的细胞免疫效应;CpG ODN和霍乱毒素能显著提高猪繁殖与呼吸综合征疫苗的抗体产生水平;IL-2和CpG ODN在临床实验中能增强疫苗对实验动物的保护,是最具潜力的免疫佐剂。     

非洲猪瘟疫苗研制方向及进展

非洲猪瘟(African swine fever,ASF)给全球养殖业造成了巨大的威胁和挑战.非洲猪瘟病毒(African swine fever virus,ASFV)具有比寻常病毒更加巨大的基因组、迅速的变异能力和更加复杂多变的免疫逃逸机制,目前市场上仍无有效预防疫苗.科研人员几十年来,从灭活疫苗、减毒活疫苗、亚单...     

猪圆环病毒2型疫苗研究进展

猪圆环病毒2型(PCV2)感染后会导致断奶仔猪多系统衰竭综合征(PMWS)等"猪圆环病毒相关疾病"(PCVADs),给全球养猪业造成了巨大的经济损失。疫苗免疫是防控该病的有效手段,近年来市场上推出了PCV2灭活疫苗、嵌合疫苗和亚单位疫苗。PCV2变异较快,主要临床流行毒株从PCV2b逐渐演变为PCV2d,现有商业化疫苗免疫效果需进一步研究证实。论文就近年来国内外PCV2传统疫苗、新型基因工程疫苗、PCV2疫苗与其他疫苗联合免疫的研究进展进行综述,旨在为猪圆环病毒相关疾病的防控及疫苗的开发与利用提供参考。     

牛传染性鼻气管炎疫苗研究进展

牛传染性鼻气管炎(IBR)是由牛传染性鼻气管炎病毒(IBRV)感染家养牛引起的一种热性接触性传染病。由于缺乏有效的治疗性药物,因此疫苗免疫仍然是防控该病的关键措施。针对该病常用的疫苗主要有灭活疫苗和活疫苗,而基因缺失活疫苗由于具有免疫标识,已成为新型疫苗研发的主流方向。一些发达国家已利用基因缺失标记疫苗,如IBRV gE缺失疫苗,进行免疫根除计划并净化了该病。然而,由于现存的疫苗仍存在免疫抑制与潜伏感染等问题,亟需研制更有效的标记疫苗。论文就牛传染性鼻气管炎病毒的病原学特征、免疫抑制及疫苗研发进展进行综述,以期为IBR有效疫苗的研发及其在防控上的应用提供参考。     

中药有效成分对动物疫苗的免疫佐剂效果及相关机理研究进展

佐剂作为疫苗的重要组成部分,其自身的安全性及对疫苗的免疫增强效果受到广泛重视。动物疫苗佐剂种类较多,包括铝佐剂、油乳佐剂和脂质体佐剂等。但由于可应用的佐剂有限,疫苗的需求量增大,因此寻求更加安全有效的疫苗佐剂成为新的研究热潮。中药具有易获取、毒性低和免疫活性强等特点,有潜力成为新型疫苗佐剂。笔者对中药有效成分的佐剂活性、联合疫苗后的免疫调节效果及作用机制进行综述,阐明中药有效成分作为动物疫苗佐剂的可能性及研究进展,为新型佐剂的研制提供理论依据。     

Human and bovine respiratory syncytial virus vaccine research and development

Human (HRSV) and bovine (BRSV) respiratory syncytial viruses (RSV) are two closely related viruses, which are the most important causative agents of respiratory tract infections of young children and calves, respectively. BRSV vaccines have been available for nearly 2 decades. They probably have reduced the prevalence of RSV infection but their efficacy needs improvement. In contrast, despite decades of research, there is no currently licensed vaccine for the prevention of HRSV disease. Development of a HRSV vaccine for infants has been hindered by the lack of a relevant animal model that develops disease, the need to immunize immunologically immature young infants, the difficulty for live vaccines to find the right balance between attenuation and immunogenicity, and the risk of vaccine-associated disease. During the past 15 years, intensive research into a HRSV vaccine has yielded vaccine candidates, which have been evaluated in animal models and, for some of them, in clinical trials in humans. Recent formulations have focused on subunit vaccines with specific CD4+ Th-1 immune response-activating adjuvants and on genetically engineered live attenuated vaccines. It is likely that different HRSV vaccines and/or combinations of vaccines used sequentially will be needed for the various populations at risk. This review discusses the recent advances in RSV vaccine development.     

Powder and particle-mediated approaches for delivery of DNA and protein vaccines into the epidermis

The epidermis of the skin is both a sensitive immune organ and a practical target site for vaccine administration. However, administration of vaccines into the epidermis is difficult to achieve using conventional vaccine delivery methods employing a needle and syringe. A needle-free vaccine delivery system has been developed that efficiently delivers powdered or particulate DNA and protein vaccines into the epidermal tissue. The delivery system can be used to directly transfect antigen presenting cells (APCs) by formulating DNA or protein vaccines onto gold particles (particle-mediated immunization). Antigen can be directly presented to the immune system by the transfected APCs. Antigen can also be expressed and secreted by transfected keratinocytes and picked up by resident APCs through the exogenous antigen presentation pathway. Alternatively, protein antigens can be formulated into a powder and delivered into the extracellular environment where they are picked up by APCs (epidermal powder immunization). Using any of these formulations, epidermal immunization offers the advantage of efficiently delivering vaccines into the APC-rich epidermis. Recent studies demonstrate that epidermal vaccine delivery induces humoral, cellular, and protective immune responses against infectious diseases in both laboratory animals and man.     

Present and future of veterinary viral vaccinology: a review

This review deals briefly with some key developments in veterinary vaccinology, lists the types of vaccines that are used for vaccinations commonly performed in food animals as well as in companion animals, and indicates that the practising veterinarian can select the best vaccine by comparing the results of efficacy studies. Diva (Differentiating Infected from Vaccinated Animals; also termed marker) vaccines and companion diagnostic tests have been developed that can be used for progammes aimed to control or eradicate virus infections. Vaccine-induced herd immunity, which can be measured relatively easily when diva vaccines are used, is a crucial issue in such programmes. Current vaccine research follows many routes towards novel vaccines, which can be divided into non-replicating ('killed') and replicating ('live') vaccines. Promising trends are the development of DNA vaccination, vector vaccines, and attenuation of DNA and RNA viruses by DNA technology. The lack of (in vitro) correlates of vaccine protection markedly hampers progress in vaccine research. Various characteristics of an 'ideal' vaccine are listed, such as multivalency and the induction of lifelong immunity after one non-invasive administration in animals with maternal immunity. Future research should be aimed at developing vaccines that approach the ideal as closely as possible and which are directed against diseases not yet controlled by vaccination and against newly emerging diseases.     

内蒙古地区牛羊口蹄疫灭活疫苗的免疫效果比较研究

为准确掌握牛羊口蹄疫疫苗免疫效果,2012年对内蒙古自治区的牛羊口蹄疫O—AsiaI型双价灭活疫苗和牛羊口蹄疫A型灭活疫苗免疫效果进行了监测。采用液相阻断ELISA方法。共检测了8个旗县23018份免疫牛羊口蹄疫O—AsiaI型双价灭活疫苗和牛羊口蹄疫A型灭活疫苗15日、30日、60日的血清中口蹄疫免疫抗体水平。结果显示,牛羊口蹄疫疫苗免疫效果总体良好,免疫抗体合格率超过了70％。规模化奶牛养殖场免疫效果稳定,散养地区免疫效果稳定性差,且不同厂家的疫苗免疫效果不同,加强免疫后A、B、D三个厂家抗体合格率能达到100％,C厂家的免疫效果较差,抗体合格率为93-3％。采用3ABC—ELISA检测试剂盒对部分地区牛羊进行感染抗体检测,结果为阴性。     

Vaccination against chlamydial infections of man and animals

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.