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1.
Molecular technology has given us a greater insight into the aetiology of disease, the functioning of the immune system and the mode of action of veterinary pathogens. The knowledge gained has been used to develop new vaccines with specific, reactive antigens which elicit protective immune mediated responses (humoral and/or cell mediated) in the host. These vaccines should not burden the immune system by initiating responses against non-essential antigens. However, the efficacy of these vaccines is only as good as the delivery technology or route used to present them to the immune system. Some vaccines, traditionally given by the parenteral route, are now given by the natural route; either orally or intranasally. Two major advantages, often interrelated, are the rapid onset of immunity and stimulation of the local, mucosal immunity. These new technologies are now making an impact on current vaccine development. The balance has to be found between what is technologically feasible and what will provide at least as good a protective immunity as current, conventional vaccines. As new and emerging diseases appear globally, new opportunities arise for molecular and conventional technologies to be applied to both the development and delivery of novel vaccines, as well as the improvement of vaccines in current use.  相似文献   

2.
Bovine schistosomosis, caused by Schistosoma bovis, constitutes a serious veterinary problem in many parts of the world. The vaccination approaches for the control of bovine schistosomosis include the use of irradiation-attenuated S. bovis cercarial or schistosomular vaccines, S. bovis adult worms or whole-egg antigens and defined antigen vaccine. Irradiated S. bovis cercarial or schistosomular vaccines provide partial protection against S. bovis infection. However, this type of vaccine requires live infectious cercariae or viable schistosomula for induction of protection. Unfortunately, experimental immunizations with dead schistosome antigens have been largely unsuccessful. The surge of new techniques in cellular immunology and molecular biology has made possible the development of potential candidate vaccine antigens from various species of schistosomes including S. bovis. The efficiency of these vaccines has been evaluated in experimentally infected calves. These vaccines will probably replace the irradiated S. bovis vaccines. A broad-spectrum antischistosome vaccine which can kill a variety of human and animal schistosome species is yet to be produced.  相似文献   

3.
New approaches in vaccine development   总被引:4,自引:0,他引:4  
In the last century, vaccines have been one of the most powerful tools for preventing infectious diseases. Smallpox has been eradicated and other diseases such as poliomyelitis or measles have been reduced to very low levels in many regions of the world. However, infectious diseases remain the leading cause of death worldwide. Thus, the development of vaccines to prevent diseases for which no vaccine currently exists such as AIDS or malaria as well as the improvement of efficacy and safety of existing vaccines remains a high priority. Achieving such ambitious goals in a near future will certainly require a strong modification of the methods that have been used so far to identify vaccine candidates. In particular, modern vaccinology could strongly benefit of the latest developments of molecular biology and immunology. Here, we will discuss some potential applications of the increasing knowledge of pathogen genomes as well as the immune system for the discovery of new antigenic targets and the development of new strategies of vaccination.  相似文献   

4.
Recent developments in veterinary vaccinology   总被引:1,自引:0,他引:1  
Advancement in technology and science and our detailed knowledge of immunology, molecular biology, microbiology, and biochemistry among other basic science disciplines have defined new directions for vaccine development strategies. The applicability of genetic engineering and proteomics along with other new technologies have played pivotal roles in introducing novel ideas in vaccinology, and resulted in developing new vaccines and improving the quality of existing ones. Subunit vaccines, recombinant vaccines, DNA vaccines and vectored vaccines are rapidly gaining scientific and public acceptance as the new generation of vaccines and are seriously considered as alternatives to current conventional vaccines. The present review focuses on recent advances in veterinary vaccinology and addresses the effects and impact of modern microbiology, immunology, and molecular biology.  相似文献   

5.
Parasite vaccines--a reality?   总被引:40,自引:0,他引:40  
Over the last decade, the anti-parasitics market has been the fastest growing sector of the overall $18 billion animal health market. While drugs for the treatment of parasites of livestock still dominate this sector and will continue to be developed or re-formulated, because of consumer demands for chemical-free food and of concerns regarding the environment and animal welfare there is a growing interest in the development of safe and effective vaccines. There is also a call for vaccines in the lucrative $3 billion-plus companion animal market. These demands for vaccines will add a greater impetus to an area that has seen tremendous success in the last 15 years. A number of anti-parasite vaccines have been developed, e.g. the recombinant 45w and EG95 oncosphere proteins against Taenia ovis and Echinococcus granulosis, respectively, and the Bm86 vaccine against Boophilus microplus. In addition, the cathepsin L vaccines against the liver fluke, Fasciola hepatica, and the H11 vaccine against Haemonchus contortus are progressing well. There are also many additional vaccine candidates for H. contortus and for other nematodes such as Ostertagia and Trichostrongylus spp. that may ultimately lead to broad-spectrum gastrointestinal worm vaccines. Live or attenuated-live vaccines are available for the control of avian coccidiosis, toxplasmosis in sheep and anaplasmosis in cattle, although molecular vaccines against protozoans are still proving elusive. The wealth of information in genomics, proteomics and immunology that has been forthcoming together will new methods of vaccine production and delivery should see many new vaccines reach the marketplace in the near future.  相似文献   

6.
Feline immunodeficiency virus (FIV) is a natural infection of domestic cats that results in acquired immunodeficiency syndrome resembling human immunodeficiency virus (HIV) infection in humans. The worldwide prevalence of FIV infection in domestic cats has been reported to range from 1 to 28%. Hence, an effective FIV vaccine will have an important impact on veterinary medicine in addition to being used as a small animal AIDS model for humans. Since the discovery of FIV reported in 1987, FIV vaccine research has pursued both molecular and conventional vaccine approaches toward the development of a commercial product. Published FIV vaccine trial results from 1998 to the present have been compiled to update the veterinary clinical and research communities on the immunologic and experimental efficacy status of these vaccines. A brief report is included on the outcome of the 10 years of collaborative work between industry and academia which led to recent USDA approval of the first animal lentivirus vaccine, the dual-subtype FIV vaccine. The immunogenicity and efficacy of the experimental prototype, dual-subtype FIV vaccine and the efficacy of the currently approved commercial, dual-subtype FIV vaccine (Fel-O-Vax FIV) are discussed. Potential cross-reactivity complications between commercial FIV diagnostic tests, Idexx Snap Combo Test and Western blot assays, and sera from previously vaccinated cats are also discussed. Finally, recommendations are made for unbiased critical testing of new FIV vaccines, the currently USDA approved vaccine, and future vaccines in development.  相似文献   

7.
Virus-like particle (VLP) composed of outer shell but no genome of virus mimics the natural configuration of authentic virion and has no characteristics of self-replication. A close resemblance to native viruses in molecular scaffolds and an absence of genomes make VLPs effectively elicit both humoral and cell-mediated immune responses even with no requirement of adjuvant for vaccines. As effective immunogens, characterized by high immunogenicity and safety, VLPs have been employed in production of human vaccines, such as the licensed vaccines of hepatitis B virus and human papillomavirus. However, there has been no report of licensed veterinary VLP vaccine worldwide as yet. Despite the wide application in vaccination, both the conventional inactivated and live attenuated vaccines for animals are subject to potential limitations due to incomplete inactivation and reversion to virulence. Therefore, those conventional vaccines may, to some extent, be replaced with the VLP-based vaccines conferring higher protection and safety to vaccinated animals. Here, we review the current status of VLPs as veterinary vaccines, and discuss the characteristics and problems associated with generating VLPs for different animal viruses.  相似文献   

8.
猪圆环病毒2型(PCV2)有多个免疫学和毒力上重要的抗原表位,这些表位为疫苗和诊断制剂的设计提供了理论依据。近年来PCV2弱毒疫苗、灭活疫苗、亚单位疫苗、活载体疫苗和DNA疫苗等多种疫苗已取得新的研究进展和实际应用,且PCV2疫苗在种猪和仔猪中的应用效果良好。此外,羧甲基新茯苓多糖、谷氨酸、精氨酸和硒等免疫增强剂及营养物质均有助于提高PCV2感染动物的机体免疫力。为更好地防控猪圆环病毒病,作者对PCV2疫苗相关研究进行综述。  相似文献   

9.
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   

10.
口蹄疫感染性克隆疫苗的发展前景   总被引:2,自引:0,他引:2  
口蹄疫是一种严重威胁畜牧业发展的重要传染病 ,目前世界上许多国家和地区都有该病的流行与发生。开展新型口蹄疫疫苗的研究一直是口蹄疫防制技术的一项重要内容。鉴于传统疫苗所存在的诸多缺点 ,人们先后研制开发了口蹄疫的第二代基因工程苗和第三代基因疫苗 ,这些新型疫苗都具有一定的优越性 ,显示出进一步发展的潜力。文章着重讨论了在感染性 c DNA的基础上所构建的一类新型基因疫苗—感染性克隆疫苗及其发展前景。感染性克隆疫苗不仅继承了以往基因疫苗的许多优点 ,而且克服了其表达量低 ,免疫效果不理想的缺点 ,为新型疫苗的研制提供了一种新的思路  相似文献   

11.
口蹄疫感染性克隆疫苗的发展前景   总被引:1,自引:0,他引:1  
口蹄疫是一种严重威胁畜牧业发展的重要传染病,目前世界上许多国家和地区都有该病的流行与发生。开展新型口蹄疫疫苗的研究一直是口蹄疫防制技术的一项重要内容。鉴于传统疫苗所存在的诸多缺点,人们先后研制开发了口蹄疫的第二代基因工程苗和第三代基因疫苗,这些新型疫苗都具有一定的优越性,显示出进一步发展的潜力。文章着重讨论了在感染性cDNA的基础上所构建的一类新型基因疫苗-感染性克隆疫苗及其发展前景。感染性克隆疫苗不仅继承了以往基因疫苗的许多优点,而且克服了其表达量低,免疫效果不理想的缺点,为新型疫苗的研制提供了一种新的思路。  相似文献   

12.
Advances in vaccine technology are occurring in the molecular techniques used to develop vaccines and in the assessment of vaccine efficacy, allowing more complete characterization of vaccine-induced immunity correlating to protection. FIV vaccine development has closely mirrored and occasionally surpassed the development of HIV-1 vaccine, leading to first licensed technology. This review will discuss technological advances in vaccine designs, challenge infection assessment, and characterization of vaccine immunity in the context of the protection detected with prototype and commercial dual-subtype FIV vaccines and in relation to HIV-1.  相似文献   

13.
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   

14.
In many countries, test-and-slaughter policies based on tuberculin skin testing have made a significant impact on the control of bovine tuberculosis (caused by infection with Mycobacterium bovis). However, in some countries these policies have not proved as effective and improved disease control strategies are required (including improved diagnostic tests and development of vaccines). The host pathogen interactions in bovine tuberculosis are very complex. While studies of the disease in naturally infected field cases of bovine tuberculosis have provided valuable information, detailed knowledge can also be gained through studies of disease models. A number of studies have developed M. bovis infection models employing a range of routes and challenge doses. An early objective was assessment of vaccine efficiency, and models of infection remain central to current work in this area. Development of the intra-nasal and intra-tracheal models have also advanced our understanding of the kinetics of the immune response. In many of these studies, understanding of pathogenesis has been improved by definition of the cells that respond to infection and those that are instrumental in modulation of host responses. Experimental models of infection have been adapted to study cattle to cattle transmission, modeling one of the fundamental routes of infection. This review provides a historical perspective on the types of experimental models used in over 100 years of research and outlines new opportunities to refine those methods for bovine and human tuberculosis and to contribute to improved diagnostics, advanced understanding of immunology and vaccine design.  相似文献   

15.
Ovine enzootic abortion (OEA) is caused by the obligate intracellular Gram-negative bacterium Chlamydia abortus. OEA remains a common cause of infectious abortion in many sheep-rearing countries despite the existence of commercially available vaccines that protect against the disease. There are a number of confounding factors that influence the uptake and use of these vaccines, which includes an inability to discriminate between infected and vaccinated animals (DIVA) using conventional serological diagnostic techniques. This suggests that the immunity elicited by current vaccines is similar to that observed in convalescent, immune sheep that have experienced OEA. The existence of these vaccines provides an opportunity to understand how protection against OEA is elicited and also to understand why vaccines can occasionally appear to fail, as has been reported recently for OEA. Interferon-gamma (IFN-γ), the cytokine that classically defines Th1-type adaptive immunity, is a strong correlate of protection against OEA in sheep and has been shown to inhibit the growth of C. abortus in vitro. Humoral immunity to C. abortus is observed in both vaccinated and naturally infected sheep, but antibody responses tend to be used more as diagnostic markers than targets for strategic vaccine design. A future successful DIVA vaccine against OEA should aim to elicit the immunological correlate of protection (IFN-γ) concomitantly with an antibody profile that is distinct from that of the natural infection. Such an approach requires careful selection of protective components of C. abortus combined with an effective delivery system that elicits IFN-γ-producing CD4+ve memory T cells.  相似文献   

16.
Detection of classical swine fever virus (CSFV) can be achieved by a range of assays of which the most commonly used are: immunohistochemical and virus culture techniques. New developments have enabled the detection of viral proteins by enzyme-linked immunosorbent assays (ELISAs) and the detection of the viral genome by RT- PCR. So far, laboratory findings show that the latter assays may supplement or replace the conventional techniques in the near future. The detection of serum antibody against structural and non-structural proteins of CSFV has been improved by developments in recombinant DNA techniques and has lead to a range of ELISAs. Although the characteristics of these ELISAs are excellent, positive results still need to be confirmed in the virus neutralization test. The available amount of sequence data enables diagnosticians to type strains of CSFV as different by comparing several parts of the genome. In some cases, this can provide conclusive evidence if a primary or secondary outbreak has been detected. Increased efforts focused on the retrieval of relevant data on the introduction of CSFV in a pig holding and the spread of CSFV in- and between pig holding(s) has generated more insight into the epizootiology of the disease. A successful control and eradication programme for classical swine fever (CSF) can consist of zoosanitary measures and/or vaccination. The latter can compromise the export of live pigs and pig products considerably unless marker vaccines have been used. Several studies were performed to determine the efficacy of an E2 subunit vaccine and live recombinant vaccine candidates. Firstly, we determined the 95% protective dose of an E2 subunit vaccine at 32 microg E2 per dosage after a single application. Further studies with a single administration of the subunit vaccine showed that: the vaccine was stable for a prolonged period after production, was able to reduce horizontal and vertical transmission of CSFV among vaccinated pigs, and provided protection for at least 6 months. An E(rns) antibody discriminatory assay was developed for use in combination with the subunit vaccine. Evaluation of the E(rns) ELISA showed that the sensitivity of the assay was lower than but that the specificity was equal to that of existing antibody assays. Two live recombinant marker vaccines were evaluated for the induction of clinical protection and reduction of transmission of CSFV shortly after vaccination. Results showed that these vaccines provided good clinical protection 1 week after a single vaccination. Research has shown that marker vaccines can be used in the future to support the control and eradication of CSFV.  相似文献   

17.
Influenza A viruses of the H3N8 subtype are a major cause of respiratory disease in horses. Subclinical infection with virus shedding can occur in vaccinated horses, particularly where there is a mismatch between the vaccine strains and the virus strains circulating in the field. Such infections contribute to the spread of the disease. Rapid diagnostic techniques are available for detection of virus antigen and can be used as an aid in control programmes. Improvements have been made to methods of standardising inactivated virus vaccines, and a direct relationship between vaccine potency measured by single radial diffusion and vaccine-induced antibody measured by single radial haemolysis has been demonstrated. Improved adjuvants and antigenic presentation systems extend the duration of immunity induced by inactivated virus vaccines, but high levels of antibody are required for protection against field infection. In addition to circulating antibody, infection with influenza virus stimulates mucosal and cellular immunity; unlike immunity to inactivated virus vaccines, infection-induced immunity is not dependent on the presence of circulating antibody to HA. Live attenuated or vectored equine influenza vaccines, which may better mimic the immunity generated by influenza infection than inactivated virus vaccines, are now available. Mathematical modelling based upon experimental and field data has been applied to examine issues relating to vaccine efficacy at the population level. A vaccine strain selection system has been implemented and a more global approach to the surveillance of equine influenza is being developed.  相似文献   

18.
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.  相似文献   

19.
20.
Several characteristics of BHV-1 have contributed to the successful development of both conventional and marker vaccines. BHV-1 is a stable virus, which grows to high titers in vitro, has a limited host range and causes acute viremic infections. Furthermore, the protective antigens, as well as the antigens that are suitable as marker, are present in the predominant virus isolates and induce significant and long-lasting immune responses, both in na?ve and in previously vaccinated animals. In many parts of the world including North-America control of BHV-1 is achieved by vaccination with conventional attenuated or inactivated vaccines. With parts of Europe being BHV-1 free, the ability to differentiate infected from vaccinated animals has become critical as a trading tool. Live and killed gE-deleted marker vaccines are now widely used in Europe, in combination with gE-based diagnostic tests to monitor cattle. However, several issues remain to be resolved. BHV-1 causes latency, which creates a need for stringent management practices in case eradication is to be achieved. Since intramuscular delivery with a syringe and needle leads to considerable tissue damage, needle-free delivery methods should be adopted for beef cattle. Furthermore, conventional inactivated and attenuated vaccines are less efficacious in neonates, so alternative vaccine types such as CpG adjuvanted protein vaccines or DNA vaccines are required for effective vaccination of this age group.  相似文献   

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