AGO2蛋白介导缺陷型流感病毒免疫应答的机制研究

缺陷型流感病毒是含有缺陷型病毒粒子(defective viral particles, DPs)的流感病毒，具有干扰完整病毒复制和刺激宿主免疫反应的功能。申请人最新研究发现A型流感病毒（IAV）感染肥大细胞可产生DPs，且DPs的免疫应答由AGO2蛋白介导，其机制尚未见报道。基于申请人前期研究，我们推测外泌体在AGO2介导DPs免疫应答过程中发挥了重要作用。为此，首先分离鉴定来源于肥大细胞DPs诱导宿主细胞所产生的外泌体，检测外泌体中AGO2蛋白的表达，并探明KRAS-MEK/ERK信号通路在AGO2分选进入外泌体过程的调控作用；其次，揭示含AGO2蛋白的外泌体迁移至感染细胞调控病毒复制和宿主免疫应答的机制；最后，分离肥大细胞产生的表达AGO2的外泌体并对其抗病毒效果进行体内实验验证。该研究结果将为缺陷型流感病毒的免疫应答机制提供科学依据，也为IAV的防治开辟新的思路。

Defective influenza virus is influenza virus that contains defective viral particles (DPs), which can interfere with the replication of infectious viruses and stimulate the innate immune response of host cells. Our latest study showed that DPs were propagated abundantly in mast cells following IAV infection, and immune response of DPs could be mediated by AGO2 protein. However, the molecular mechanism has not been reported to date. Based on our previous study, we speculate that exosomes play an important role in the AGO2-mediated immune response of DPs. Thus, we will firstly isolate and identify the presence of AGO2 in exosomes from host cells that is induced by DPs from mast cells as well as regulation of KRAS-MEK/ERK signaling pathway in the process of AGO2 sorting into exosomes. Then, the migration of these exosomes into infected cells and release of AGO2 protein will be detected as well as the effects of AGO2 protein on viral replication and immune response in the host will be furtherly analyzed. Finally, the antiviral effect of isolated exosomes containing AGO2 protein was observed in vivo. The study will provide scientific evidence for the mechanism of immune response of the defective influenza virus, and a novel insight into the progress of new strategies to fight IAVs infection.