H5N1病毒HA蛋白对小鼠外周免疫器官的损伤及其机制

目的研究H5N1病毒HA蛋白作用于小鼠后对其外周免疫器官脾脏的损伤其相关细胞因子的分泌。方法通过昆虫-杆状病毒表达系统表达H5N1病毒HA蛋白,并经镍亲和磁珠纯化,将重组的HA蛋白作用于小鼠,72 h后,取其脾脏,观察其镜下形态学变化;分离脾细胞并培养,检测其细胞因子的分泌。结果脾组织病理表现为局部性弥漫性肺泡损伤,单核细胞侵润,脾脏肿胀,毛细血管充血,生发中心局部结构破坏,有空泡样改变,淋巴细胞减少,见较多大单核吞噬细胞。HA蛋白预处理的小鼠其脾细胞分泌IP-10、MCP-1a、Rantes较PBS预处理的小鼠明显增高;同时HA蛋白预处理组小鼠脾细胞在LPS刺激后分泌的IFN-γ、IP-10、MCP-1a、Rantes较PBS处理的小鼠其脾细胞明显增高。结论气道给予H5N1 HA表面膜蛋白能够始动异常的免疫应答,引起急性肺损伤和外周淋巴器官与免疫细胞破坏。

Hemagglutinin protein of avian influenza virus H5N1 in immune injury of peripheral immune organs and its possible mechanism

This study aims to investigate the role of recombinant hemagglutinin protein(HA) of avian influenza virus(AVI) H5N1 in immune injury of peripheral immune organ spleen and the related cytokines secretion in mice.By using insect-baculovirus expression system and nickel affinity magnet beads,HA protein of AVI H5N1 was recombined and was used in mice.Seventy-two hours after HA protein instillation,the lungs and spleens were isolated form the mice.Pathological examination revealed spleen swelling,destruction of local structure of germinal center,vacuolar changes and a decrease in lymphocyte,while lung pathological examination showed diffuse alveolar damage,inflammatory cell infiltration in mice challenged by HA.The injury index of spleen cells after LPS stimulation in HA pretreatment was higher than that in those of PBS pretreatment.And under basal condition,the levels of IP-10,MCP-1a and Rantes released from the spleen cells of mice in HA pretreatment were significantly higher than those from the mice of PBS pretreatment group(P< 0.05).Twenty-four hours after LPS stimulation,the levels of IFN-γ,IP-10,MCP-1a,and Rantes released from the spleen cells of HA pre-treated mice was significantly higher than those from PBS pretreated mice(P< 0.05).In conclusion,the H5N1 virus HA membrane protein by intratracheal instillation elicits a strong pathological immune response in the host,resulting in immune injury of peripheral lymphoid organs and immune cells and acute lung injury.