Developing Avirulent Rabies Virus Vaccines

描述（由申请人提供）：狂犬病仍然是一种公共卫生威胁，每年造成7万多人死亡。人类感染狂犬病病毒（RV）主要是通过狂犬病家畜或野生动物的叮咬。因此，控制家养动物和野生动物中的RV感染，不仅可以降低这些动物的死亡率，还可以降低人类暴露的风险。对经常处于危险中的人进行暴露前疫苗接种可以进一步预防人类狂犬病，对被狂犬病或疑似狂犬病动物咬伤的人进行暴露后疫苗接种也可以预防人类狂犬病。目前，灭活RV疫苗用于免疫家养宠物动物。纯化和灭活RV疫苗用于暴露前或暴露后的人类。尽管灭活RV疫苗是有效的，但它们存在问题。首先，也是大多数情况下，需要在很长一段时间内多次接种疫苗，以刺激保护性免疫反应。此外，目前的组织培养疫苗价格昂贵，因此大多数需要接种疫苗的人（在发展中国家）负担不起。因此，需要开发更有效和负担得起的RV疫苗。在上一个资助期，我们制造了糖蛋白和核蛋白突变的构建体，导致在神经系统中复制和传播的能力降低。在这里，我们建议继续开发无毒力的活RV疫苗，通过构建具有增强的诱导先天性免疫应答能力的突变体RV（通过将IFN或趋化因子基因插入RV基因组），使用最先进的反向遗传学技术。我们的建议是基于我们最近的发现。减毒RV诱导强烈的先天免疫应答，特别是IFN和趋化因子，从而限制病毒在CNS内的传播。构建表达IFN或趋化因子的重组RV的基本原理是，这种改变的RV最有可能具有增强的免疫原性，并且可以用作人和动物的无毒力活疫苗。此外，诱导的先天免疫反应不仅具有直接抗病毒的功能，而且还可以招募炎性细胞，从而杀死感染的细胞。这些特性将使这些重组RV疫苗特别适合于暴露后治疗。

DESCRIPTION (provided by applicant): Rabies still presents a public health threat causing more than 70,000 human deaths each year. Humans are infected with rabies virus (RV) mostly through bites from rabid domestic or wild animals. Controlling RV infection in domestic and wildlife animals, therefore not only reduces the mortality in these animals but also reduces the risk of human exposure. Pre-exposure vaccinations for people who are constantly at risk further prevent human rabies, as do post-exposure immunization for people who are bitten by rabid or suspected rabied animals. Currently, inactivated RV vaccines are used to immunize domestic pet animals. Purified and inactivated RV vaccines are used for humans in pre- or post-exposure settings. Although inactivated RV vaccines are efficacious, they have problems. First and for most, multiple doses of vaccines over a long period of time are required to stimulate protective immune responses. Furthermore, current tissue culture vaccines are expensive, thus most people in need of vaccination (in developing countries) cannot afford them. Hence, there is a need to develop more efficacious and affordable RV vaccines. In the previous funding period, we made constructs with mutation on both the glycoprotein and the nucleoprotein, resulting in reduced ability to replicate and spread in the nervous system. Here we propose to continue developing avirulent live RV vaccines by constructing mutant RV with enhanced ability to induce innate immune responses (by inserting IFN or chemokine genes into the RV genome), using the state-of-the-art reverse genetics technology. Our proposal is based on our recent findings. Attenuated RV induces strong innate immune responses, particularly IFN and chemokines, thus limiting virus spread within the CNS. The rationale for construction of recombinant RV expressing IFN or chemokines is that such altered RV most likely will have enhanced immunogenicity and can be used as live avirulent vaccines for humans and animals. Furthermore, induction of innate immune responses will not only have a direct anti-viral functions, but also recruit inflammatory cells that can kill infected cells. Such characterists will make these recombinant RV vaccines particularly suitable for post-exposure treatment.