[Correlation of hepatitis B virus X antigen expression with liver cell apoptosis].

OBJECTIVE: To study the roles of hepatitis B virus (HBV) X antigen (HBxAg) in development of HBV-related liver diseases and carcinogenesis. METHODS: Liver tissues were collected from patients with HBV infection (HBV carriers, n = 14; chronic hepatitis B (CHB), n = 24), HBV-related liver cirrhosis (LC, n = 20), or hepatocellular carcinoma (HCC, n = 20). Immunohistochemistry was used to detect the expression of HBxAg and the host apoptosis-related genes Fas and Fas ligand (Fas-L). The correlations of HBxAg with HBV DNA level in serum, inflammation grade, and fibrosis stage were statistically analyzed. Liver inflammation grade and fibrosis stage were in accordance with Knodell standard. x2test and Fisher's exact test were adopted in count data, x2split method was adopted in pariwise comparisons between multiple samples, Rank-sum test was adopted in ranked data, Spearman rank correlation analysis was adopted in correlation analysis. RESULTS: The rates of HBxAg-positivity were similar between the patients with HBV infection (71.1%), LC (60.0%), and HCC (65.0%) (x2= 0.754, P = 0.686). The rates of Fas- and Fas-L-positivity in liver cells were also similar between the three groups (Fas: 28.9% vs. 20.0% vs. 5.0%, x2= 4.667, P = 0.101; Fas-L: 36.8% vs. 50.0% vs. 60.0%, x2= 2.988, P = 0.225). However, the positive rate of Fas in lymphocytes of liver tissue was significantly higher in the HCC patients than in the HBV-infected patients (90.0% vs. 68.4%, Z = -4.360, P = 0.00001). The expressions of HBxAg and Fas-L corresponded to regions of severe inflammation in tissues from LC patients and some HCC patients. Furthermore, the expression of HBxAg was positively correlated with Fas (r = 0.304, P = 0.02) and Fas-L (r = 0.368, P = 0.004) in the HBV-infected patients and LC patients, and the expression of Fas was positively correlated with that of Fas-L (r = 0.448, P = 0.0004). Patients with high and medium loads of HBV DNA showed significantly higher rates of HBxAg-positivity than those with low loads (88.9% and 69.2% vs. 26.7%, P less than 0.05). CONCLUSION: In the early stage of chronic HBV infection, HBxAg may induce liver cell apoptosis by up-regulating Fas expression, and in the later stage, HBxAg may induce immune escape by up-regulating Fas-L expression in liver cells. Together, HBxAg and high HBV DNA load may promote chronic HBV infection and progression to hepatocarcinogenesis.

[The cloning, expression, purification and immunological identification of wild-type and mutant hepatitis B virus X gene in pGEX-6P-2 system].

To settle the foundation for the future research on the influence of wild and mutant (A1762T/ G1764A) HBV X gene on the progress of chronic HBV infection and hepatic tumorigenicity, wild and mutant (A1762T/G1764A) HBxAgs expression system was constructed. The wild and mutant (A1762T/ G1764A) HBV X genes were amplified with polymerase chain reaction (PCR) from HBV genome were inserted into pGEX-6P-2 and confirmed by sequencing respectively. Prokaryotic expression vectors pGEX-6P-2-hbvx(w) and pGEX-6P-2-hbvx(m) (A1762T/G1764A) were constructed and transformed to Trans1-blue; wild and mutant HBxAgs were expressed through IPTG induction respectively; after refolding of inclusion body, the wild and mutant HBxAgs were purified with GSTrap FF; and analysised by SDS-PAGE, Western blot and ELISA. SDS-PAGE analysis showed that the expression system was able to express target protein efficiently; the concentrations of purified wild HBxAg and mutant HBxAg were 4.88 mg/mL and 5.07 mg/mL respectively; Western blot analysis certified both the wild HBxAg and the mutant HBxAg could be recognized by the same monoclonal antibody against HBxAg; the two expressed fusion antigens coated in microtiter plate were able to react with the sera of HBV infected patients but not with the sera from healthy donors in ELISA. Results demonstrated that we successfully established a system for expression of hepatitis B x antigen and lay the foundation for further research on the role and molecular mechanisms of the mutant HBxAg in the progress of chronic HBV infection and hepatic tumorigenicity.

[A clinical study on CD178 positive T lymphocyte in hemorrhagic fever with renal syndrome].

BACKGROUND: To further probe into the role of CD178 in the pathogenesis of hemorrhagic fever with renal syndrome (HFRS). METHODS: The expression of CD178 and HLA-DR on T cell subsets in peripheral blood of patients with HFRS and their dynamic changes were detected by Flow cytometry. RESULTS: CD4+ CD178+ and CD8+ CD178+ T lymphocytes both in fever and polyuria phases were significantly higher than those in normal controls, while there was no significant difference between the both phases of HFRS (P > 0.05). CD178 expression on CD4+ HLA-DR+ and CD8+ HLA-DR+ T lymphocytes were significantly higher than those in normal controls (P < 0.05, P < 0.01, P < 0.001, P < 0.001), while there was no significant difference between CD4+ HLA-DR+ and CD8+ HLA-DR+ T lymphocytes (P > 0.05). CONCLUSION: CD178 was expressed on both CD4+ and CD8+ T cell subsets, but mainly on CD8+ T cell subsets both in early stage and in later stage in the pathogenesis of HFRS. Cytotoxic T lymphocyte (CTL) might kill target cells infected by hantavirus (HV) and eliminate HV via cell apoptosis mediated by CD178 in early stage of HFRS. In later stage of HFRS, CD178 might reduce antigen-specific T lymphocytes by activation induced cell death (AICD) and help to maintain the homeostasis of immune system.