猪生殖与呼吸综合征病毒感染Marc-145细胞的病毒形态发生和细胞超微结构观察

Studies on Porcine Reproductive and Respiratory Syndrome Virus Morphogenesis in Marc-145 Cell and the Ultrastructural Changes of the Infected Cells

以猪生殖与呼吸综合征病毒四川分离株PRRSV-SC1株感染体外培养的Marc-145细胞为模型,通过透射电镜对PRRSV的病毒形态发生学和宿主细胞超微结构的动态变化规律进行研究。结果显示,病毒粒子呈球形,有囊膜,大小约45-65nm,内含直径约25-30nm的核衣壳。病毒感染细胞后以细胞内吞方式进入细胞,在胞浆内复制,装配好的病毒以出芽或细胞外分泌释放到细胞外。感染细胞超微结构变化主要表现为:细胞胞浆空泡增多,内质网扩张,线粒体增生、嵴肿胀、脱落,最后空泡化,细胞表面的微绒毛脱落,出现典型的细胞凋亡特征,并观察到凋亡小体,最后整个细胞裂解、破碎。

Electron microscopy was employed for ultrastructural observation of Marc-145 cells infected with porcine reproductive and respiratory syndrome virus （PRRSV） SC1 strain and studied the virus morphogenesis in infected cells. The results demonstrated that PRRSV was spherical and enveloped. The virion is 45-65 nm in diameter and its nucleocapsid was approximately 25 - 30 nm. PRRSV entered Marc-145 cells by endocytosis, and replicated in the cytoplasm. The mature viruses were released from infected cells by budding or exocytosis. The main ultrastructural changes of the infected cells were as follows： increased number of cytoplasmic vacuoles, dilated endoplasmic reticulum, mitochondria underwent hyperplasia with its ridges swollen, sloughed, and eventually vacuolated. Typical apoptosis was also observed in the infected Marc-145 cells, which included microvilli sloughing off the cell, appearance of apoptotic bodies and cell fragmentation.