Improving the Translational Potential of a Prime-and-Trap Malaria Vaccine

项目总结 疟疾是一种寄生虫病，每年造成约2.29亿人感染和40万人死亡。卓有成效的 由于寄生虫对药物治疗的抗药性迅速增长，迫切需要疫苗。肝期(LS)为 寄生虫生命周期中的一个关键瓶颈。如果LS停止，这将防止血液期感染， 临床疾病和传播。针对子孢子(SPZ)的辐射减毒子孢子(RAS)疫苗 和LS，并可通过诱导保护性抗体和CD8+T细胞来产生灭菌保护。在临床前阶段 研究发现，RAS诱导了驻留在肝脏中的CD8+T细胞亚群，称为肝脏常驻记忆T 对长期LS保护至关重要的(TRM)细胞。尽管RAS具有很强的免疫原性， 许多抗原(包括环子孢子蛋白(CSP))，RAS疫苗的效力在不同的 由于需要反复大剂量静脉注射(IV)，实施工作受到阻碍。 Prime-and-Trap是一种两步疫苗策略，旨在通过以下方式简化和改进仅RAS免疫 将编码CSP抗原的皮内递送DNA与后来单次静脉注射RAS相结合，以指导 并“捕获”肝脏中被激活和扩张的T细胞。这一策略增加了CD8+肝脏Trm的保护性 细胞，但对CSP启动抗原的依赖和对大剂量静脉注射的要求- 在诱捕时给予RAS，构成转换到较大动物模型和人类的障碍。这项建议 将提供临床前研究，以改善原发和诱捕疟疾的疗效和转化潜力 疫苗。我们假设，Prime-And-Trap可以通过a)减少剂量或改变交付来改进 RAS陷阱的路线，以及b)通过识别额外的保护性LS抗原来启动。 在目标1中，我们将研究联合使用糖脂佐剂7DW8对RAS捕获的改善。 5.我们将评估在不降低免疫原性或保护作用的情况下提供RAS的低剂量和非静脉注射方法。 在目标2中，我们将识别保护性LS抗原以供启动。最近，一种核糖体蛋白(RP)被鉴定为 一种有效的疫苗抗原，能在小鼠体内诱导保护性的肝脏Trm细胞。如果有保护作用，RP就会成为有吸引力的疫苗 目标，因为它们高度保守和丰富。在这里，我们将研究总体的RP免疫原性和 在Prime-and-Trap中诱导CD8+T细胞。这项研究将在华盛顿大学进行， 申请人组建了一支具有疟疾生物学、疫苗等专业知识的多学科指导团队 发育和T细胞免疫学。已经设计了一项培训计划，以提供补充课程 全球健康、出席会议和导师会议，为申请者培养必要的技能 完成她提出的研究，成为一名独立的研究员。总而言之，Prime-and-Trap是一个 多功能疟疾候选疫苗，可使用单一RAS剂量诱导保护性LS免疫，并 值得进一步研究，以提高其翻译潜力。关于这一候选疫苗的研究 为候选人在疫苗转译科学领域提供最佳培训机会。

PROJECT SUMMARY Malaria is a parasitic disease responsible for ~229 million infections and 400,000 deaths annually. An effective vaccine is urgently needed as parasites are rapidly growing resistant to drug treatments. The liver stage (LS) is a critical bottleneck in the parasite life cycle. If the LS was stopped, this would prevent blood stage infection, clinical disease, and transmission. Radiation-attenuated sporozoite (RAS) vaccines target the sporozoite (spz) and LS and can result in sterilizing protection by inducing protective antibodies and CD8+ T cells. In pre-clinical studies, RAS induced a subset of memory CD8+ T cells that reside in the liver called liver resident memory T (Trm) cells that were critical for long-term LS protection. Although RAS is highly immunogenic and presents many antigens (including the circumsporozoite protein (CSP)), RAS vaccine efficacy varies across different populations, and implementation is hindered by requirements for repeated high-dose intravenous (IV) injections. Prime-and-Trap is a two-step vaccine strategy intended to simplify and improve on RAS-only immunization by combining intradermally delivered DNA encoding the CSP antigen with a later single IV dose of RAS to direct and “trap” the activated and expanding T cells in the liver. This strategy increased protective CD8+ liver Trm cells in mice, but the reliance on the CSP priming antigen alone and the requirement for a high dose of IV- administered RAS upon trapping pose hurdles for translation to larger animal models and humans. This proposal will provide pre-clinical research to improve the efficacy and translational potential of the Prime-and-Trap malaria vaccine. We hypothesize that Prime-and-Trap can be improved by a) reducing the dose or altering the delivery route for the RAS trap, and b) by identifying additional protective LS antigens for priming. In Aim 1, we will investigate improvements of RAS trapping with co-administration of glycolipid adjuvant 7DW8- 5. We will evaluate low dose and non-IV methods to deliver RAS without reducing immunogenicity or protection. In Aim 2, we will identify protective LS antigens for priming. Recently, a ribosomal protein (RP) was identified as a potent vaccine antigen that induces protective liver Trm cells in mice. If protective, RP make attractive vaccine targets since they are highly conserved and abundant. Here, we will investigate overall RP immunogenicity and induction of CD8+ T cells in Prime-and-Trap. The research will be carried out at the University of Washington, where the applicant has assembled a multidisciplinary mentorship team with expertise in malaria biology, vaccine development, and T cell immunology. A training plan has been designed to provide supplemental coursework in global health, conference attendance, and mentorship meetings to build necessary skills for the applicant to complete her proposed research and become an independent researcher. In summary, Prime-and-Trap is a versatile malaria vaccine candidate that can induce protective LS immunity using a single RAS dose and warrants further investigation to improve its translational potential. The research on this vaccine candidate provides an optimal training opportunity for the candidate in the field of vaccine translational sciences.