Novel Vaccine Strategies Against Ebola Virus

描述(申请人提供)：这是一个项目的修订申请，重点是开发预防埃博拉病毒(EBOV)引起的疾病的有效疫苗。埃博拉病毒是一种丝状病毒，是高致命性出血热的病原体。埃博拉病毒可通过人与人之间的接触传播，从而构成引发疫情爆发的高威胁。本课题组一直致力于开发抗病毒感染的VLP疫苗，我们的研究结果表明，利用重组杆状病毒表达系统在昆虫细胞中生产的EBOV VLP产量高，具有DC刺激活性，并能诱导强烈的抗体反应，中和EBOV GP介导的病毒感染(Ye等，2006)，表明这种VLP可以作为安全有效的疫苗来诱导对EBOV感染的保护性免疫。此外，我们还在最近的研究中发现，与单独使用DNA或VLP疫苗相比，DNA和VLP疫苗(DNA/VLP)混合免疫可诱导更高水平的抗体和细胞免疫反应。利用这一新的疫苗策略获得的两个非病毒载体疫苗平台的综合好处表明，它有可能开发出针对EBOV感染的有效疫苗。在这个项目中，我们将测试新的DNA/VLP疫苗策略将引起对EBOV感染的强大细胞和抗体反应，以及佐剂的使用将进一步增强这种反应的诱导的假设，目的是获得一种能够对EBOV感染提供快速和持久保护的疫苗策略。具体目的1.我们将比较DNA/VLP疫苗单独与DNA或VLP疫苗诱导的免疫反应，并确定DNA/VLP疫苗策略是否优于对EBOV感染的快速(接种次数减少)和长期(接种后6个月)保护。此外，我们将使用转基因小鼠模型来研究DNA/VLP免疫诱导抗体和T细胞应答增强的潜在机制，这将为进一步开发更有效的EBOV疫苗以及其他病原体提供有指导意义的信息。具体目的2.研究佐剂在DNA/VLP免疫中的作用，并与单独接种DNA或VLP进行比较，确定是否可以获得一种有效的疫苗策略，通过一次免疫来诱导对EBOV感染的保护性免疫。此外，我们还将进一步研究DNA/VLP疫苗在豚鼠身上的效力，以评估它们在不同小型实验动物模型中对抗EBOV感染的效力，目的是确定DNA/VLP疫苗策略在未来评估非人类灵长类动物模型中的潜力。埃博拉病毒(EBOV)是一种丝状病毒，是高致死性出血热的病原体。埃博拉病毒可通过人与人之间的接触传播，因此构成疫情暴发的高度威胁。我们之前已经展示了两个非病毒载体疫苗平台的综合好处以及它在开发针对EBOV感染的有效疫苗方面的潜力。在这个项目中，我们将测试新的DNA/VLP疫苗策略将引发针对EBOV感染的强大细胞和抗体反应，以及佐剂的使用将进一步增强此类反应的诱导的假设。

DESCRIPTION (provided by applicant): This is a revised application for a project focused on development of an effective vaccine for prevention of disease caused by Ebola virus (EBOV), a filovirus which is an etiologic agent of highly lethal hemorrhagic fever. Ebola virus can be transmitted via person-to-person contact, thus posing a high threat of causing an epidemic outbreak. Our group has been engaged in the development of VLP vaccines against virus infection, and our results have shown that EBOV VLPs produced in insect cells using the recombinant baculovirus expression system, which gives high VLP production yield, exhibit DC-stimulating activity and induce strong antibody responses that neutralize EBOV GP mediated virus infection (Ye et al., 2006), indicating that such VLPs could serve as safe and effective vaccines to induce protective immunity against EBOV infection. Furthermore, we also made the finding in recent studies that immunization with a mixture of DNA and VLP vaccines (DNA/VLP) induced higher levels of both antibody and cellular immune responses in comparison to immunization with DNA or VLP vaccines alone. The combined benefit of two non-viral-vector based vaccine platforms obtained with this novel vaccine strategy demonstrates its potential for the development of an efficacious vaccine against EBOV infection. In this project, we will test the hypotheses that the novel DNA/VLP vaccine strategy will elicit strong cellular and antibody responses against EBOV infection and that the use of an adjuvant will further augment induction of such responses, with the aim to obtain a vaccine strategy that can confer rapid as well as long lasting protection against EBOV infection. Specific Aim 1. We will compare immune responses induced by DNA/VLP immunization with DNA or VLP vaccines alone and determine whether the DNA/VLP vaccine strategy is superior to confer rapid (with reduced number of vaccinations) as well as long lasting (at six months after vaccinations) protection against EBOV infection. Moreover, we will employ a transgenic mouse model to investigate the underlying mechanism for the induction of enhanced antibody and T cell responses by DNA/VLP immunization, which will provide instructive information for further development of more potent vaccines against EBOV as well as other pathogens. Specific Aim 2. We will investigate the effect of adjuvant on DNA/VLP vaccination in comparison with DNA or VLP vaccination alone, and determine whether a potent vaccine strategy can be obtained to elicit protective immunity against EBOV infection by a single immunization. Moreover, we will further investigate the efficacy of DNA/VLP vaccines in guinea pigs to assess their potency against EBOV infection in a different small laboratory animal model, with the aim to determine the potential of the DNA/VLP vaccine strategy for future evaluation in the non-human primate model. Ebola virus (EBOV) is a filovirus which is an etiologic agent of highly lethal hemorrhagic fever. Ebola virus can be transmitted via person-to-person contact, thus posing a high threat of an epidemic outbreak. We have previously shown the combined benefit of two non-viral-vector based vaccine platforms and its potential for the development of an efficacious vaccine against EBOV infection. In this project we will test the hypotheses that the novel DNA/VLP vaccine strategy will elicit strong cellular and antibody responses against EBOV infection and that the use of an adjuvant will further augment induction of such responses.