Abstract:

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 IFNλ3  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 IRF7.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.

Key words: interferon regulatory factor 7;hepatocytes;viral infection;immune response