IDENTIFY NOVEL NEUTRALIZATION-SENSITIVE EPITOPES OF COXIELLA BURNETII

摘要 Q热是一种由专性细胞内革兰氏阴性细菌引起的世界性人畜共患疾病， 伯氏柯克斯体。人类Q热可能发展成一种严重的慢性疾病，可能是致命的。虽然这件事 以前被武器化并目前被归类为B类选择剂的生物体，没有疫苗 在美国可用于预防人类Q热的商业用途。因此，创建一个安全和 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。至 为了实现这一目标，这一新的R21应用程序旨在探索设计多价Q热的可行性 靶向新型中和敏感表位的疫苗，这些表位既包括非依赖的伯氏杆菌T细胞表位，也包括T细胞表位 依赖抗原。尽管伯氏梭菌是一种专性的细胞内细菌病原体，但我们最近的工作 显示福尔马林灭活九里I期全细胞疫苗(PIV)诱导的保护依赖 在B细胞上产生保护性T细胞非依赖的IgM和T细胞依赖的Ig G。因此，激活的抗原 产生PIV特异性IgM和IgG的B细胞有望成为有希望的候选疫苗。有趣的是， 我们以前的研究表明，一种模拟伯氏梭菌I相脂多糖(PI-LPS)的多肽 保护表位(M1E41920)与锁孔帽状血蓝蛋白(m1E41920-klh)偶联 对伯氏梭菌感染有显著的保护作用。这一发现支持m1E41920作为疫苗的用途 预防人类Q热的候选药物。然而，m1E41920-KLH没有提供与 全细胞疫苗。因此，该应用的总体目标是鉴定额外的保护肽 模拟T细胞非依赖性抗原和PIV特异性保护蛋白抗原以加强保护 由这种基于m1E41920的单价疫苗授予。为了实现这一目标，我们提出了两个具体的 旨在检验中心假设，即对多种中和敏感表位的体液反应 伯氏梭菌T细胞非依赖性抗原和T细胞依赖性抗原都是产生相同水平的 作为PIV的保护。目标1将确定更多可以模拟T细胞上多个保护性表位的模拟表位 不依赖细胞的抗原。目的2鉴定PIV特异性T细胞依赖的免疫球蛋白识别蛋白。 这个项目意义重大，因为它是开发安全有效的疫苗的关键一步。 这可以提供与PIV同等水平的预防Q热的保护。在这个项目完成后，我们 有望定义第一种针对两者的新的中和敏感表位的多价Q热疫苗 伯氏梭菌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.