Development and Testing of Novel Glanders Vaccine Candidates

描述(申请人提供)：马来伯克霍尔德氏菌，扁桃体的病原体，在人类和动物中引起严重的疾病，是生物战和恐怖主义的潜在病原体。目前，还没有可用于疾病免疫的人类或兽医疫苗。我们研究的长期目标之一是研究人员鉴定和鉴定马来杆菌表达的保护性抗原，并利用它们开发新的粘液疫苗候选。以往的研究表明，马来芽胞杆菌表达的O-多糖既是毒力决定簇，又是保护性抗原。因此，这种碳水化合物部分已成为我们实验室目前正在开发的各种腺体亚单位疫苗候选的重要组成部分。最近，我们发现泰兰伯克霍尔德氏菌是一种亲缘关系密切但非致病的物种，可以通过基因操作来表达类马来杆菌OPS抗原。这些观察结果为拟议的研究提供了基础。我们推测，使用从泰兰巴氏杆菌OPS突变体中分离的抗原，可以安全和经济地构建基于OPS的粘虫疫苗候选。目前研究方案的目标是合成各种基于OPS的糖偶联物，并在腺体动物模型中评估它们的保护能力。为了验证这一假设，我们制定了以下具体目标：具体目标1.构建基于OPS的糖偶联物，用于免疫扁桃体。这将通过将泰兰巴氏杆菌来源的OPS抗原与各种特性良好的载体蛋白共价连接来实现。特定目的2.鉴定OPS糖偶联物免疫小鼠的体液免疫应答。这将通过用糖结合物免疫小鼠群来实现。免疫前后的血清免疫球蛋白滴度将通过抗原特异性的酶联免疫吸附试验进行定量。还将评估血清杀菌和吞噬细胞活性。具体目的3.在腺体动物模型中确定以OPS为基础的糖偶联物的保护能力。为了做到这一点，将用在特定目标2中确定的两种最具免疫原性的糖偶联物对小鼠进行免疫接种。然后，小鼠将被带有毒力的马来杆菌的气雾剂攻击，并在实验过程中监测它们的存活情况。总而言之，这些研究将显著增加我们对OPS抗原保护能力的理解，并为未来腺体疫苗候选的合理设计提供重要线索。 与公共卫生相关：马来伯克霍尔德氏菌是生物战和恐怖主义的精选制剂和潜在制剂。目前，还没有人类或兽医疫苗可用于预防扁桃体感染。这项拟议的研究将探索使用基于OPS的新型糖偶联物来接种这种细菌病原体引起的疾病的可行性，并表征抗OPS多克隆抗体反应在这方面的重要性。

DESCRIPTION (provided by applicant): Burkholderia mallei, the etiologic agent of glanders, cause severe disease in humans and animals and are a potential agent of biological warfare and terrorism. At present, there are no human or veterinary vaccines available for immunization against disease. One of the long term objectives of our research is the investigator to identify and characterize protective antigens expressed by B. mallei and use them to develop novel glanders vaccine candidates. Previous studies have demonstrated that the O-polysaccharide (OPS) expressed by B. mallei is both a virulence determinant and a protective antigen. Consequently, this carbohydrate moiety has become an important component of the various glanders subunit vaccine candidates that we are currently developing in our lab. Recently, we have shown that Burkholderia thailandensis, a closely related but non-pathogenic species, can be genetically manipulated to express B. mallei-like OPS antigens. These observations provide the basis for the proposed research. We hypothesize that OPS-based glanders vaccine candidates can be constructed safely and cost-effectively using antigens isolated from B. thailandensis OPS mutants. The goal of the current research proposal is to synthesize a variety of OPS-based glycoconjugates and evaluate their protective capacity in an animal model of glanders. To test this hypothesis, we have formulated the following specific aims: Specific Aim 1. Construct OPS-based glycoconjugates for immunization against glanders. This will be accomplished by covalently linking B. thailandensis-derived OPS antigens to a variety of well characterized carrier proteins. Specific Aim 2. Characterize the humoral immune responses of mice immunized with the OPS- based glycoconjugates. This will be accomplished by immunizing groups of mice with the glycoconjugates. Pre- and post-immune serum immunoglobulin titers will be quantitated via antigen specific enzyme-linked immunosorbent assay. Serum bactericidal and opsonophagocytic activities will also be assessed. Specific Aim 3. Determine the protective capacity of OPS-based glycoconjugates in an animal model of glanders. To accomplish this, groups of mice will be vaccinated with the two most immunogenic glycoconjugates identified in Specific Aim 2. Mice will then be challenged by aerosol with virulent B. mallei and their survival monitored over the course of the experiment. Collectively, these studies will significantly increase our understanding regarding the protective capacity of OPS antigens and yield important clues towards the rational design of future glanders vaccines candidates. PUBLIC HEALTH RELEVANCE: Burkholderia mallei is a select agent and a potential agent of biological warfare and terrorism. At present, there are no human or veterinary vaccines available for immunization against glanders. The proposed research will explore the feasibility of using novel OPS-based glycoconjugates to vaccinate against disease caused by this bacterial pathogen as well as characterize the importance of anti-OPS polyclonal antibody responses in this regard.