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

项目概要 疟疾是一种寄生虫病，每年导致约 2.29 亿人感染和 40 万人死亡。一个有效的 由于寄生虫对药物治疗的耐药性迅速增强，因此迫切需要疫苗。肝脏阶段（LS）是 寄生虫生命周期的关键瓶颈。如果停止 LS，这将防止血期感染， 临床疾病和传播。辐射减毒子孢子 (RAS) 疫苗以子孢子 (spz) 为目标 和 LS，并可通过诱导保护性抗体和 CD8 T 细胞产生灭菌保护。在临床前 研究发现，RAS 诱导了驻留在肝脏中的记忆 CD8 T 细胞子集，称为肝常驻记忆 T (Trm) 细胞对于长期 LS 保护至关重要。尽管 RAS 具有高度免疫原性并呈现 由于许多抗原（包括环子孢子蛋白 (CSP)），RAS 疫苗的功效因不同抗原而异 人群，并且由于需要重复大剂量静脉（IV）注射的要求而阻碍了实施。 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 的免疫接种： 将皮内递送的编码 CSP 抗原的 DNA 与随后单次 IV 剂量的 RAS 相结合，以指导 并将激活和扩张的 T 细胞“捕获”在肝脏中。该策略增加了保护性 CD8 肝脏 Trm 小鼠细胞，但仅依赖 CSP 引发抗原，并且需要高剂量的 IV- 在捕获后施用 RAS 会给转化为更大的动物模型和人类带来障碍。这个提议 将提供临床前研究，以提高 Prime-and-Trap 疟疾的功效和转化潜力 疫苗。我们假设可以通过 a) 减少剂量或改变输送来改进 Prime-and-Trap RAS 陷阱的途径，以及 b) 通过识别用于启动的额外保护性 LS 抗原。 在目标 1 中，我们将研究联合使用糖脂佐剂 7DW8- 来改善 RAS 捕获 5. 我们将评估低剂量和非 IV 方法来递送 RAS，而不降低免疫原性或保护作用。 在目标 2 中，我们将鉴定用于启动的保护性 LS 抗原。最近，核糖体蛋白（RP）被鉴定为 一种有效的疫苗抗原，可在小鼠体内诱导保护性肝 Trm 细胞。如果具有保护作用，RP 可以成为有吸引力的疫苗 目标，因为它们高度保守且丰富。在这里，我们将研究总体 RP 免疫原性和 在 Prime-and-Trap 中诱导 CD8 T 细胞。该研究将在华盛顿大学进行， 申请人组建了一支多学科指导团队，拥有疟疾生物学、疫苗等方面的专业知识 发育和T细胞免疫学。培训计划旨在提供以下方面的补充课程： 全球健康、会议出席和指导会议，以培养申请人必要的技能 完成她提议的研究并成为一名独立研究员。总而言之，Prime-and-Trap 是一种 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， 值得进一步研究以提高其转化潜力。该候选疫苗的研究 为疫苗转化科学领域的候选人提供最佳的培训机会。

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.