Developing Avirulent Rabies Virus Vaccines

描述(申请人提供)：狂犬病仍然是一种公共卫生威胁，每年导致超过7万人死亡。人类主要通过狂犬病家畜或野生动物的叮咬感染狂犬病病毒(RV)。因此，控制家畜和野生动物的轮状病毒感染，不仅可以降低这些动物的死亡率，还可以降低人类接触轮状病毒的风险。对经常处于危险中的人进行暴露前接种进一步预防人类狂犬病，对被狂犬病或疑似狂犬病动物叮咬的人进行暴露后免疫也是如此。目前，轮状病毒灭活疫苗用于家养宠物的免疫。纯化和灭活的轮状病毒疫苗用于暴露前或暴露后的人类。虽然灭活轮状病毒疫苗是有效的，但它们也存在问题。首先，对大多数人来说，需要在很长一段时间内接种多剂疫苗来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，有必要开发更有效和负担得起的轮状病毒疫苗。在之前的资助期间，我们在糖蛋白和核蛋白上构建了突变的结构，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活RV疫苗，利用最先进的反向遗传学技术，构建具有增强诱导先天性免疫反应能力的突变体RV(通过将干扰素或趋化因子基因插入RV基因组)。我们的建议是基于我们最近的发现。减毒的轮状病毒可诱导强烈的先天免疫反应，特别是干扰素和趋化因子，从而限制病毒在中枢神经系统内的传播。构建表达干扰素或趋化因子的重组轮状病毒的基本原理是，这种改变的轮状病毒很可能具有增强的免疫原性，并可用作人和动物的无毒活疫苗。此外，诱导先天免疫反应不仅具有直接的抗病毒功能，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轮状病毒疫苗特别适合暴露后治疗。

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.