HBV感染人胎盘滋养层细胞机制的初步探讨

The mechanism of HBV infection of human trophoblast cell

目的采用透射电镜观察HBV体外感染人胎盘滋养层细胞的超微结构变化。方法HBV体外感染人胎盘滋养层细胞。ELISA检测培养上清中HBsAg，PCR检测细胞培养上清和滋养层细胞中的HBVDNA。HBV荧光定量PCR检测细胞培养上清中HBVDNA量（拷贝／ml）。透射电镜观察滋养层细胞的超微结构。结果感染组滋养层细胞培养上清中HBsAg在PBS清洗后12h时A值为0．942，96h时上升为1．264。PCR检测感染组细胞培养上清和感染组细胞HBVDNA均为阳性。PBS彻底清洗后0、12、36、60、84h感染组细胞培养上清的HBVDNA分别为：〈10^3，3×10^4，6×10^5，5×10^5，3×10^5拷贝／ml。透射电镜观察到感染组滋养层细胞膜附近存在包涵素（Clathrin）形式的内吞小体形成，并且发现内吞小体内存在病毒颗粒样结构。在感染组细胞粗面内质网内发现HBsAg特异性的纤维丝状结构。结论HBV可能经包涵素依赖的细胞内吞形式进入滋养层细胞，进而实现感染细胞或通过胞释作用将病毒排至细胞的对侧而实现穿越滋养层细胞屏障。

Objective To observe the changes of human trophoblast cells after infected with hepatitis B virus. Methods HBV positive serum was used to infect human trophoblast cells in vitro. HBsAg in cell culture medium were detected by ELISA method and HBV DNA in cell culture medium and cells were detected by PCR method. HBV fluorescence polymerase chain reaction diagnose kit were used to detect the HBV DNA concentration. Ultra structure of trophoblast cells were observed with transmission electron microscopy （TEM）. Results HBsAg could be detected in infection group by ELISA. Infection group cell culture medium and infection group cells were HBV DNA positive. HBV DNA concentrations in HBV infection cell culture medium in 0,12,36, 60,84 h after extensively PBS washed were 〈 10^3 , 3×10^4,6×10^5,5×10^5,3×10^5 copies/ml. HBV infected trophoblast cells were found many forms of endosomes, some of which contents virus like particle. Conclusion HBV might take advantage of clathrin-mediated endocytosis to enter trophoblast cell, which might lead to cell infection or across the cell bar by transcytosis.