SARS冠状病毒S蛋白对细胞损伤的机制研究

The possible mechanism of SARS-CoV S protein induced cell damage

目的研究SARS-CoV的S蛋白作用于内皮细胞后对趋化因子IP-10和其他细胞因子生成的影响,及作用于支气管上皮对外周血单个核细胞的趋化作用。方法通过昆虫-杆状病毒表达系统表达SARS-CoV的S蛋白,并经镍亲和磁珠纯化,将重组的S蛋白作用于人脐静脉内皮细胞,观察其形态学变化并检测IP-10和其他细胞因子的变化;作用于人支气管上皮细胞16HBE后观察其对外周血单个核细胞的趋化作用。结果S蛋白作用于人内皮细胞可引起细胞内出现空泡,细胞变圆有脱落,随时间延长细胞破碎溶解,IFN-γ组也可见小部分细胞脱落但未见空泡变性,脱落程度较S-PR轻。基础状态下内皮细胞并不生成IP-10,S蛋白作用12 h后即可见IP-10生成达(88.88±21.20)pg/ml,呈显著量效反应。但对其他参与免疫反应的Th1/Th2细胞因子及趋化因子影响不明显。而IFN-γ不仅能诱导内皮细胞IP-10的增高,而且能诱导其他因子的增高。S蛋白刺激上皮细胞可产生趋化因子,对单个核细胞有募集作用。结论①SARS-CoV的S蛋白可通过其S蛋白诱导内皮细胞合成释放IP-10,损害内皮细胞,从而启动或加重免疫病理过程。②SARS-CoV的S蛋白诱导IP-10在宿主细胞的生成是IFN-γ不依赖的。③SARS-CoV的S蛋白可刺激上皮细胞产生趋化因子,将单个核细胞有募集至感染部位,激活或加重进一步的肺损伤。

Objective To investigate the role of the recombinant S protein of SARS- CoV in the induction of ehemokine IP- 10 and other eytokines in human endothelial cell, and the effect of airway epithelial cells stimulated by S protein on human peripheral blood mononuelear cells （PBMCs）. Methods Using insect - baeulovirns expression system and Nickel affinity Magnet Beads, S protein of SARS - CoV was recombined and was used to stimulate cultured human umbilical vein endothelial eells（HUVECs）.Morphological changes of HUVECs were observed by microscope. Levels of IP- 10 and eytokines involved in immunoreaction in response to virus infection were detected in the supematants of those cells cultured with the S protein by liquid chip system. Human airway epithelial cells（16HBE） were stimulated by S protein for 24 hours and the ehemotatie effect of 16HBE on PBMCs was assessed. Results Vacuoles were found in part of HUVECs after S protein stimulation. The HUVECs became round and even disrupted with time. Under normal condition , no detectable IP - 10 was found in HUVECs . A high level of IP - 10 （88.88±21.20 pg/ml） was detected in the HUVECs 12 hours after S protein stimulation, and S protein induced IP - 10 production was demonstrated at a dose - dependent manner. Other eytokines and ehemokines involved in immunity against general virus did not increase. In contrast , IFN - γ not ordy induced IP - 10 production but also induced other eytokines. HBEs stimulated by S protein induced some ehemotactie factors, which were able to recruit PBMCs. Conclusion ①S protein of SARS - CoV induced a high level of IP- 10 in endothelial cells , which in turn damaged endothelial cells, leading to initiation or acceleration of the process of the immune damage in the lung. ②S protein of SARS - CoV induced IP - 10 production independent to IFN - γ. ③Some ehemotaxins were produced in airway epithelial cells after being stimulated by S protein of SARS - CoV , which attracted PBMCs to the inflammation area and triggered the process of lung injury.