A novel DNA-launched live attenuated Chikungunya vaccine

描述（由申请人提供）：本申请的主要目标是设计、生产和评估一种针对基孔肯雅病毒（CHIKV）的概念性新型疫苗。我们提出了一种“感染性”DNA （i-DNA）作为CHIKV疫苗的新技术。该技术的一个独特之处在于，CHIKV减毒活疫苗是从i-DNA质粒在体内发射的。在i-DNA中，在优化的真核启动子和调控序列的背景下，将修饰的IND减毒活疫苗181/25的RNA基因组全长拷贝置于质粒中。基因组病毒RNA在体内的转录导致减毒病毒在疫苗受体组织中的有限复制，并诱导保护性免疫反应。由于i-DNA代表一个分子克隆，它将产生一个统一的减毒病毒种群，从而潜在地提高安全性。我们还将通过对C-E2-E1基因的翻译密码子进行反优化，制备两种i-DNA变体，以提高遗传稳定性和疫苗安全性。将在体外和体内与目前的181/25减毒活疫苗一起对实验性CHIKV i-DNA疫苗进行评估。将与印度金奈的Sri Ramachandra大学合作，用一组来自最近临床分离的CHIKV人抗血清对疫苗抗原进行检测。免疫原性和安全性将在年轻和老年小鼠以及免疫抑制仓鼠中确定。因此，候选i-DNA疫苗的特性将在不同年龄和免疫状态的临床前模型中进行评估，这些模型模拟人类群体，并将提供疫苗安全性和免疫原性特征的准确测定。总之，i-DNA疫苗将结合DNA疫苗的简单性和减毒活疫苗的特殊功效。i-DNA可以潜在地提高安全性，不需要冷链，易于制造和在紧急情况下扩大规模。此外，细菌产生的i-DNA将包含CpG基序，这有望激活先天免疫反应并提高免疫原性。如果成功，这项技术可能是基孔肯雅热疫苗接种的革命性解决方案。

DESCRIPTION (provided by applicant): The main goal of this application is the design, production and evaluation of a conceptually novel vaccine against Chikungunya virus (CHIKV). We propose a novel technology of "infectious" DNA (i-DNA) as CHIKV vaccine. A unique feature of this technology is that live attenuated CHIKV vaccine is launched in vivo from the i-DNA plasmid. In the i-DNA, the full-length copy of RNA genome of modified live attenuated IND vaccine 181/25 is placed in the plasmid in the context of optimized eukaryotic promoter and regulatory sequences. Transcription of the genomic viral RNA in vivo results in limited replication of attenuated virus in the tissues of vaccine recipient and induction of a protective immune response. Since the i-DNA represents a molecular clone, it will generate a uniform population of attenuated virus thus potentially improving safety. We will also prepare two i-DNA variants by de-optimization of translational codons within C-E2-E1 genes with the view to enhance genetic stability and vaccine safety. Experimental CHIKV i-DNA vaccines will be evaluated in vitro and in vivo along with the current 181/25 live attenuated vaccine. The vaccine antigens will be probed with a panel of human antisera from recent clinical CHIKV isolates in partnership with Sri Ramachandra University, Chennai, India. Immunogenicity and safety profiles will be determined in the young and aged mice as well as in immunosuppressed hamsters. Thus, characteristics of candidate i-DNA vaccines will be evaluated in the preclinical models of various age and immune status, which mimics human population and will provide accurate determination of safety and immunogenicity profiles of the vaccines. In summary, i-DNA vaccination will combine the simplicity of DNA vaccines with the exceptional efficacy of live attenuated vaccines. The i-DNA can potentially improve safety, does not require cold chain and is easy to manufacture and scale-up in emergency scenarios. Further, bacterially generated i-DNA will contain CpG motifs, which are expected to activate innate immune responses and improve immunogenicity. If successful, this technology may represent a revolutionary solution for vaccination against Chikungunya fever.