RESUMO
<p><b>OBJECTIVE</b>To investigate the effect of an adenovirus vector containing murine interleukin-21 gene (Ad-GFP-mIL-21) in virus clearance and on the production of HBV-specific antibodies in mice with persistent HBV infection.</p><p><b>METHODS</b>ELISA and Western blot analysis were used to detect the expression of mIL-21 in the supernatant and cytoplasm of cultured HepG2.2.15 cells after infection by Ad-GFP-mIL-21. Mouse models of chronic HBV infection established by in vivo transduction with rAAV8-1.3HBV were divided into 3 groups for treatment 12 weeks later with injection of Ad-GFP-mIL-21, GFP recombinant adenovirus or PBS via the tail vein. Serum levels of HBsAg, HBsAb, HBcAb, and mIL-21 in the mice were detected using ELISA, and the expression of Ad-GFP-mIL-21 in the organs was observed by fluorescent microscopy at different time points after the injection.</p><p><b>RESULTS</b>Ad-GFP-mIL-21 was capable of infecting HepG2.2.15 cells in vitro, and the levels of mIL-21 in the supernatant were correlated with the titers of adenovirus administered and the infection time. In the mice with persistent HBV infection, green fluorescence expression was observed almost exclusively in the liver on day 4 after injection of Ad-GFP-mIL21, and serum levels of IL-21 increased significantly compared with the level before treatment (P<0.05). Although HBsAb was undetectable in both Ad-GFP-mIL21-injected and control mice on day 13, a significantly higher serum level of HBcAb was detected in the mice with Ad-GFP-mIL21 injection (P<0.05).</p><p><b>CONCLUSION</b>Ad-GFP-mIL-21 can efficiently express mIL-21 in mice with chronic HBV infection to downregulate serum levels of HBsAg and promote HBcAb production, suggesting its efficacy in controlling chronic HBV infection.</p>
RESUMO
<p><b>OBJECTIVE</b>To analyze the characteristics of lymphocyte phenotypes in hepatitis B virus (HBV) transgenic mice and the effect of exogenous interferon-α on virological profiles and lymphocytes phenotypes of the mice.</p><p><b>METHODS</b>HBV transgenic mice and wild-type (WT) mice were examined for serum levels of HBsAg, HBcAb, IL-21, and IL-6 using ELISA. The frequencies of CD4(+)T and CD19(+)B cells separated from the liver, spleen, and peripheral blood were detected by flow cytometry. Nine HBV transgenic mice were injected subcutaneously with recombinant mouse interferon alpha (rmIFN-α) and another 9 transgenic mice were injected with PBS, and their HBsAg, HBV DNA, IL-6, and IL-21 levels and frequencies of peripheral blood CD4(+)T and CD19(+)B cells were detected.</p><p><b>RESULTS</b>HBV transgenic mice showed a high level of HBsAg with a detectable level of HBcAb and significantly increased serum levels of IL-21 and IL-6 as compared with WT mice (P<0.05). The transgenic mice had a significantly lower frequency of CD4(+) T cells in the peripheral blood, liver and spleen (P<0.05) but a significantly higher frequency of CD19(+) B cells in the liver (P<0.05). An inverse correlation between intrahepatic CD4(+) T cell frequency and serum HBsAg level while a positive correlation between intrahepatic CD19(+) B cell frequency and HBcAb level were found in HBV transgenic mice. Administration of rmIFN-α significantly increased the frequencies of CD4(+) T and CD19(+) B cells in the peripheral blood and the serum level of IL-6 in HBV transgenic mice (P<0.05).</p><p><b>CONCLUSION</b>HBV transgenic mice have lymphocyte subset dysregulation and exogenous interferon-α can modulate the immune function of the mice by regulating the frequencies of lymphocyte subsets.</p>