Jang Yo Han, Byun Young Ho, Lee Kwang-Hee, Park Eun-Sook, Lee Yun Ha, Lee Yoon-Jae, Lee Jinhee, Kim Kyun-Hwan, Seong Baik Lin
Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
PLoS One. 2013 Oct 2;8(10):e75043. doi: 10.1371/journal.pone.0075043. eCollection 2013.
Live attenuated vaccine (LAV), mimicking natural infection, provides an excellent protection against microbial infection. The development of LAV, however, still remains highly empirical and the rational design of clinically useful LAV is scarcely available. Apoptosis and caspase activation are general host antiviral responses in virus-infected cells. Utilizing these tightly regulated host defense mechanisms, we present a novel apoptosis-triggered attenuation of viral virulence as a rational design of live attenuated vaccine with desired levels of safety, efficacy, and productivity. Mutant influenza viruses carrying caspase recognition motifs in viral NP and the interferon-antagonist NS1 proteins were highly attenuated both in vitro and in vivo by caspase-mediated cleavage of those proteins in infected cells. Both viral replication and interferon-resistance were substantially reduced, resulting in a marked attenuation of virulence of the virus. Despite pronounced attenuation, the viruses demonstrated high growth phenotype in embryonated eggs at lower temperature, ensuring its productivity. A single dose vaccination with the mutant virus elicited high levels of systemic and mucosal antibody responses and provided complete protection against both homologous and heterologous lethal challenges in mouse model. While providing a practical means to generate seasonal or pandemic influenza live vaccines, the sensitization of viral proteins to pathogen-triggered apoptotic signals presents a potentially universal, mechanism-based rational design of live vaccines against many viral infections.
减毒活疫苗（LAV）模拟自然感染，能提供出色的抗微生物感染保护。然而，LAV的研发仍然高度依赖经验，临床上有用的LAV的合理设计几乎没有。凋亡和半胱天冬酶激活是病毒感染细胞中常见的宿主抗病毒反应。利用这些严格调控的宿主防御机制，我们提出了一种新型的凋亡触发病毒毒力减弱方法，作为一种具有所需安全性、有效性和生产力水平的减毒活疫苗的合理设计。在病毒核蛋白（NP）和干扰素拮抗剂NS1蛋白中携带半胱天冬酶识别基序的突变流感病毒，在体外和体内均因感染细胞中这些蛋白的半胱天冬酶介导的切割而高度减毒。病毒复制和干扰素抗性均大幅降低，导致病毒毒力显著减弱。尽管明显减毒，但这些病毒在较低温度下的鸡胚中表现出高生长表型，确保了其生产力。用突变病毒进行单剂量疫苗接种可引发高水平的全身和黏膜抗体反应，并在小鼠模型中提供针对同源和异源致死性攻击的完全保护。在提供一种生产季节性或大流行性流感活疫苗的实用方法的同时，使病毒蛋白对病原体触发的凋亡信号敏感，为针对许多病毒感染的活疫苗提供了一种潜在的通用的、基于机制的合理设计。
