IDENTIFY NOVEL NEUTRALIZATION-SENSITIVE EPITOPES OF COXIELLA BURNETII

摘要 Q热是一种世界性的人畜共患病，由专性细胞内革兰氏阴性菌引起， 贝氏柯克斯体人类Q热可以发展成一种严重的慢性，潜在的致命疾病。虽然这 生物体以前武器化，目前被列为B类选择剂，没有疫苗是 在美国可商购获得用于预防人Q热。创造一个安全的， 预防Q热的有效疫苗仍然是公共卫生和国家生物安全的重要目标。到 为了实现这一目标，这个新的R21应用程序旨在探索设计多价Q发烧的可行性 靶向两种C.贝氏T细胞非依赖性和T细胞非依赖性 依赖性抗原尽管C. Burnetii是一种专性细胞内细菌病原体，我们最近的工作 证明福尔马林灭活的Nine Mile I期全细胞疫苗（PIV）诱导的保护作用取决于 在B细胞上产生保护性T细胞非依赖性IgM和T细胞依赖性IgG。因此，激活 产生PIV特异性IgM和IgG的B细胞预期是有希望的疫苗候选物。有趣的是， 我们以前的研究表明，C.贝氏I相脂多糖（PI-LPS） 与钥孔血蓝蛋白（m1 E41920-KLH）缀合的保护性表位（m1 E41920）赋予 对C.贝氏体感染这一发现支持m1 E41920作为疫苗的效用 预防人类Q热的候选人。然而，m1 E41920-KLH没有提供与M1 E41920-KLH相同的保护水平。 全细胞疫苗因此，本申请的总体目标是鉴定另外的保护性肽 T细胞非依赖性抗原和PIV特异性保护性蛋白抗原的模拟物，以增强保护 由这种基于m1 E41920的单价疫苗赋予。为达致这个目标，我们提出两项具体建议， 目的是检验中心假设，即体液反应的多个中和敏感表位的 两种C.贝氏体T细胞非依赖性和T细胞依赖性抗原是赋予相同水平的 保护PIV。目的1将鉴定能够模拟T细胞表面多个保护性表位的其他模拟表位 非细胞依赖性抗原。目的二是鉴定PIV特异性T细胞依赖性IgG识别的蛋白抗原。 该项目意义重大，因为它是开发安全有效疫苗的关键一步 可以提供与PIV相同水平的Q热保护。在这个项目完成后，我们 期望定义第一种多价Q热疫苗，其靶向两种病毒的新型中和敏感表位， C.贝氏体T细胞非依赖性和T细胞依赖性抗原。

Abstract Q fever is a worldwide zoonotic disease that is caused by the obligate intracellular Gram-negative bacterium, Coxiella burnetii. Human Q fever can develop into a severe chronic, potentially fatal disease. Although this organism previously weaponized and currently classified as a category B select agent, no vaccine is commercially available for the prevention of human Q fever in the US. Thus, the creation of a safe and effective vaccine for preventing Q fever remains an important goal for public health and national biosecurity. To achieve this goal, this new R21 application aims to explore the feasibility of designing a multivalent Q fever vaccine targeting novel neutralization-sensitive epitopes of both C. burnetii T cell-independent and T cell- dependent antigens. Despite C. burnetii being an obligate intracellular bacterial pathogen, our recent work demonstrated that formalin-inactivated Nine Mile phase I whole cell vaccine (PIV)-induced protection depends on B cells to produce protective T cell-independent IgM and T cell-dependent IgG. Thus, antigens that activate B cells to produce PIV-specific IgM and IgG are expected to be promising vaccine candidates. Interestingly, our previous studies demonstrated that a peptide mimic of a C. burnetii phase I lipopolysaccharides (PI-LPS) protective epitope (m1E41920) conjugated to keyhole limpet haemocyanin (m1E41920-KLH) conferred significant protection against C. burnetii infection. This finding supports the utility of m1E41920 as a vaccine candidate to prevent human Q fever. However, m1E41920-KLH did not confer the same level of protection as the whole cell vaccine. Thus, the overall objective of this application is to identify additional protective peptide mimics of T cell-independent antigens and PIV-specific protective protein antigens to enhance the protection conferred by this monovalent m1E41920-based vaccine. To achieve this objective, we propose two specific aims to test the central hypothesis that a humoral response to multiple neutralization-sensitive epitopes of both C. burnetii T cell-independent and T cell-dependent antigens is required for conferring the same level of protection as the PIV. Aim 1 will identify additional mimotopes that can mimic multiple protective epitopes on T cell-independent antigens. Aim 2 will identify PIV-specific T cell-dependent IgG recognized protein antigens. This project is significant because it is the critical step towards development of a safe and effective vaccine that can confer an equal level of protection against Q fever as the PIV. Upon the completion of this project, we expect to define the first multivalent Q fever vaccine that targets novel neutralization-sensitive epitopes of both C. burnetii T cell-independent and T cell-dependent antigens.