中文摘要：

目的：检测肝细胞中固有表达的干扰素调节因子7（IRF7）在免疫过程中的作用,揭示IRF7固有表达对肝细胞抵御病毒感染的影响。方法：以原代肝细胞、永生化肝细胞HuS-E/2以及肝肿瘤细胞株HuH-7细胞作为研究对象,利用仙台病毒（SV）感染原代肝细胞和HuH-7细胞,以RT-PCR法检测IFNα1、IFNβ、IFNλ3及视黄酸诱导基因蛋白（RIG-I）的诱导表达,以IRF7显性负性突变体表达载体pcDNA3-7DN转染HuS-E/2细胞,RT-PCR法及实时定量PCR检测上述基因的诱导变化。IRF7表达载体pcDNA3-IRF7转染HuH-7细胞后,进行2a型HCV病毒株JFH1感染,间接免疫荧光法检测HCV感染情况。结果：SV感染12 h内,HuH-7细胞中未检测到明显的IFNα1、IFNβ、IFNλ3和RIG-I的诱导表达;而在SV感染早期（3 h）,原代肝细胞中即可检测到上述基因的mRNA条带。IRF7功能受到抑制后,RT-PCR结果显示SV感染的肝细胞中上述基因表达在感染早期的mRNA条带灰度降低;实时定量PCR可见SV感染3 h内,上述基因mRNA诱导表达水平均显著降低（P〈0.001）。异位表达IRF7的HuH-7细胞中JFH1感染后未检测到明显的HCV信号。结论：肝细胞中固有IRF7的表达与细胞感染后的免疫反应密切相关,对于防御病毒感染起到重要作用。

英文摘要：

Objective To check the effect of interferon regulatory factor 7 （IRF7） in the defense against the viral infection in hepatocytes by evaluating the function of IRF7 in the immune response of hepatocytes. Methods The human primary hepatocytes, immortalized human hepatocytes HuS-E/2 and hepatoma cell line HUH-7 cells were used for this study. After Sendai virus （SV） infection, the expressions of IFNα1, IFNβ, IFNλ3, and RIG-I in hepatocytes and HUH-7 cells were detected by RT-PCR. The function of IRF7 in hepatocytes cells was blocked by transfection of the expressing plasmid of dominant negative form of IRF7 pcDNA3-7DN. The expressions of IFNα1, IFNβ, and IFNλ were detected by RT-PCR and real time PCR. The HUH-7 cells was infected with genotype 2a HCV JFH1 after transfection of the expressing plasmid of IRF7 pcDNA3-IRF7. The infection efficiency was detected with indirect immunofluorescence. Results The induction of mRNA of IFNα1, IFNβ, IFNλ3, and RIG-I was not detected in HUH-7 cells after SV infection in 12 h, while that was detected in hepatocytes at the early stage （3 h）. The expressions of the genes mentioned above were downregulated at the early stage of SV infection after the blockage of the function of IRF7, and the mRNA levels of these genes were significantly decreased in the first 3 h after SV infection in the IRF7 knockdown HuS-E/2 cells （p〈0. 001）. The signal of infection and replication of JFH1 were not detected in the HUH-7 cells with ectopic expression of IRFT. Conclusion The constitutively expressed IRF7 in hepatocytes is closely related to the immune response after infection, and plays an important role in the defense of viral infection.