Currently, clinical antiviral therapies for chronic hepatitis B virus (HBV) infection can efficiently control HBV replication.However, it remains difficult to achieve HBsAg clearance and sustains off-therapy, that is the functional cure of chronic hepatitis B ( CHB) in most of patients.Host immune responses play critical roles in HBV clearance and HBV infection control by activating innate and adaptive immune responses, resulting in improving the functional cure rate of patients with CHB.This article reviews the recent advances in immunology studies related to functional cure of CHB.

Objective:To investigate the effect of hepatitis C virus non-structural protein 4B (HCV-NS4B) on Survivin、and Caspase-3 expression,and to explore its effect on Apoptosis and proliferation of hepatocyte and its possible mechanism. Methods: By transfecting the recombinant plasmid (PCXN2-NS4B) into LO2 liver cells with liposome, the experiment was divided into : LO2 liver cells group, empty vector PCXN2 group and PCXN2-NS4B group. Flow cytometry was used to determine the expression of Caspase-3,and immunohistochemical method was used to detect the expression of Survivin. Results:PCXN2-NS4B was transfected into LO2 cells, with a stable expression.Caspase-3 expression : in LO2 liver cell group, empty vector PCXN2 group and PCXN2-NS4B group was (23.45 ± 1.57)%,(23.17 ± 1.79)% and (4.34 ± 0.59)% respectively.The difference between LO2 liver cell group and empty vector PCXN2 group was not significant (P>0.05), while between LO2 liver cell group, and PCXN2-NS4B group there was significant difference (P<0.01).Positive rate of Survivin expression in LO2 liver cells group, PCXN2 group and PCXN2 -NS4B group was 25% ,16.67% and 75% respectively. There was no significant difference between LO2 liver cells group and empty vector PCXN2 group (P>0.05); but between LO2 liver cells group and PCXN2 -NS4B group there was significant difference (P <0.05).Conclusions: ① Stable expression of the recombinant plasmid is found in transfected LO2 liver cells. ②HCV-NS4B inhibits Caspase-3 expression and promotes the expression of Survivin. ③ HCV -NS4B Inhibits liver cell apoptosis via inhibiting expression of Caspase-3 and increasing expression of Survivin.