Development of a single-dose rabies virus vaccine

摘要 全球每9分钟就有一人（通常是儿童）死于狂犬病。当前狂犬病病毒（RABV） 暴露预防（PEP）仍然复杂和昂贵，需要四到五剂灭活的RABV， 狂犬病免疫球蛋白（RIG）一剂疫苗，不需要昂贵的， 通常不可用的RIG将大大提高RABV疫苗接种的效力，降低与RABV疫苗接种相关的费用， 预防狂犬病，拯救生命。然而，在我们对B细胞如何被激活的理解上存在差距， 对基于RABV的疫苗接种的反应。在过去的35年里，分泌IgG（而不是IgM）的B细胞被认为是 通过T细胞依赖性应答单独负责疫苗诱导的抗RABV感染的保护作用， 曝光后设置。此外，B细胞获得RABV抗原的机制以前并不清楚。 知道的我们的实验室已经开始解开狂犬病特异性B细胞应答的关键属性，这些属性有助于 疫苗诱导的病毒中和抗体（VNA）的快速诱导。我们发现疫苗诱导的T细胞 细胞非依赖性（TI）和早期滤泡外T细胞依赖性（TD）B细胞应答，包括中和 IgM可以限制致病性RABV传播到CNS中，在小鼠中提供部分保护。我们也 显示游离狂犬病毒颗粒迁移到引流淋巴结中的被膜下窦巨噬细胞， 将RABV抗原直接转移至B细胞。我们的目标是利用这些发现来开发一种单剂量RABV， 疫苗方案。具体来说，我们假设一个复制缺陷，基质基因缺失的RABV为基础的， 对滤泡B细胞具有增强的嗜性的疫苗（RABV-ΔM）将迅速产生抗原特异性B细胞 分化为IgM和IgG浆细胞，从而增加早期B的动力学、幅度和质量 细胞反应。在本研究中，我们的目标是克隆、回收和鉴定RABV-Δ M疫苗 对滤泡B细胞的嗜性增强。接下来，新疫苗将在描述良好的小鼠中进行测试。 狂犬病免疫原性和暴露后保护模型。最后，我们将证实， 引入RABV-ΔM的修饰不会对安全性和稳定性产生不利影响。除了扩大 我们的知识RABV免疫，关键的见解将获得关于病毒疫苗如何相互作用， 激活滤泡B细胞以诱导针对病毒感染的快速和有效的免疫。主要里程碑在 该项目的完成是确定一种安全的疫苗接种方案，诱导有效和快速的TI 和滤泡外TD B细胞反应比多剂量人狂犬病疫苗更有效， 需要钻机。总之，能够引发快速和稳健的B细胞应答的单剂量疫苗策略 将提高人用狂犬病疫苗的效力，降低预防狂犬病的相关成本， 生活

Abstract A person, usually a child, dies of rabies every nine minutes globally. Current rabies virus (RABV) post- exposure prophylaxis (PEP) remains complicated and costly, requiring four to five doses of inactivated RABV- based vaccine plus rabies immune globulin (RIG). A single-dose vaccine that does not require expensive and often unavailable RIG would greatly increase the efficacy of RABV vaccination, reduce the cost associated with rabies prevention, and save lives. However, there is a gap in our understanding of how B cells are activated in response to RABV-based vaccination. For the last 35 years, B cells secreting IgG (but not IgM) were thought to be solely responsible for vaccine-induced protection against RABV infection via T cell-dependent responses in post-exposure settings. Furthermore, mechanisms by which B cells acquire RABV antigen were not previously known. Our laboratory has begun to unravel key attributes of rabies-specific B cell responses that contribute to the rapid induction of vaccine-induced virus neutralizing antibodies (VNAs). We showed that vaccine-induced T cell-independent (TI) and early extrafollicular T cell-dependent (TD) B cell responses, including neutralizing IgM, can limit dissemination of pathogenic RABV into the CNS, providing partial protection in mice. We also showed that free rabies particles migrate to subcapsular sinus macrophages in the draining lymph node, transferring RABV antigen directly to B cells. We aim to exploit these findings to develop a single-dose RABV vaccine regimen. Specifically, we hypothesize that a replication-deficient, matrix gene-deleted RABV-based vaccine (RABV-ΔM) with enhanced tropism to follicular B cells will result in antigen-specific B cells rapidly differentiating into IgM and IgG plasma cells, thereby increasing the kinetics, magnitude and quality of early B cell responses. In this proposal, our goals are to clone, recover and characterize RABV-ΔM-based vaccines with enhanced tropism to follicular B cells. Next, the new vaccines will be tested in well-described mouse models of rabies immunogenicity and post-exposure protection. Finally, we will confirm that the genetic modifications introduced into RABV-ΔM do not adversely affect safety and stability. In addition to expanding our knowledge of RABV immunity, key insights will be gained regarding how viral vaccines interact with and activate follicular B cells to induce rapid and potent immunity against viral infections. The major milestone at the completion of this project is the identification of a safe vaccination regimen that induces potent and rapid TI and extrafollicular TD B cell responses more effectively than the multi-dose human rabies vaccine, without the need for RIG. In summary, single-dose vaccine strategies capable of eliciting rapid and robust B cell responses will improve the efficacy of human rabies vaccines, reduce the cost associated with rabies prevention and save lives.