人肠道病毒EV71基因组释放的分子机制研究

Enterovirus 71 (EV71) causes yearly outbreaks of hand, foot, and mouth disease in Southeast Asian countries including our China. Some of the infected children develop encephalitis that can be fatal or result in permanent brain damage. There are no anti-EV71 therapeutic agents available. Here it is shown that an antibody that had been generated by using mature and immature mixture EV71 virus as antigen induced the release of genome from EV71 virions, rendering the virus non- infectious and and finally breakup. As the main object of this study, through the integrated application of Cryo-EM single particle analysis and X-ray crystallography, using a modified single particle reconstruction algorithm, several virus-antibody complex structures in this transition process have been captured in nearly atoms resolution and that explains the molecular mechanisms by which the antibody induced the release of the viral genome and ultimately disintegrated virus particles through a high-affinity binding to the 3-fold symmetry nearby. This project has a unique neutralizing antibodies as a tool, through a unique perspective on the one hand to reveal further the molecular mechanisms of structural changes in the genome release process for picornaviruses, on the one hand lay an important theoretical basis for the anti-EV71 therapeutic antibody development.

肠道病毒71型（EV71 ）是近年来引起我国和东南亚地区儿童手足口病的主要致病病原，极端情况可使患儿引发急性脑炎，致永久性脑损伤甚至死亡。目前仍无可用的抗EV71治疗性药物上市。本项目以不同组成和结构状态的全颗粒病毒混合免疫小鼠获得具有良好中和活性的单克隆抗体6G5，其能够在体外近生理条件下瞬时诱导全病毒颗粒基因组释放并整体崩解。以其为主要研究对象，通过综合应用冷冻透射电镜单颗粒重构技术和X射线晶体学手段，利用改良的单颗粒重构算法，捕捉了这一过渡过程中全病毒与抗体的数个近原子分辨率复合体三维结构，阐释其通过高亲和力结合于病毒的三次轴外围，诱导病毒基因组释放，并最终使病毒粒子崩解进而发挥中和活性的分子机制。本项目以具有独特性质的中和性抗体为工具，一方面以独特视角进一步揭示小RNA病毒在基因组释放过程中的结构变化和分子机制，一方面为抗EV71治疗性抗体的研发奠定重要理论基础。