Comprehensive analysis of different phases of chronic Hepatitis B Infection

Chronic Hepatitis B virus (HBV) infection was classified into four active phases by the EASL: HBeAg-positive chronic infection, HBeAg-positive chronic hepatitis, HBeAg-negative chronic infection and HBeAg-negative chronic hepatitis. Recently, it was observed that released HBsAg amounts, ratios of L-, M- and S-proteins and morphology of subviral particles varied by genotype (Gt). Here, we characterized the different phases of chronic HBV infection regarding HBsAg, HBcAg and particle assembly in vivo and in vitro.

Sera of patients infected with GtA or GtD of different disease phases were analyzed by HBsAg-specific Western Blot (WB) and density gradient centrifugation. HBV genomes of GtA, GtB, and GtD of representative HBeAg-negative patients with precore mutation G1896A were cloned into pUC-18 and expressed in Hepatoma cells. Corresponding wildtype genomes were used for comparison.

In sera of patients, ratios of HBsAg proteins differed among genotypes but not among different disease phases. In addition, density of HBsAg-particles varied among the genotypes but not in regard to stage of infection. In vitro, HBeAg-negative genomes showed a reduction in HBsAg expression. WB analyses indicated an accumulation of LHBs and core protein within cells. Furthermore, immunofluorescence microscopy analyses showed a perinuclear accumulation of HBsAg and a strong intranuclear localization of assembled/dimeric core protein.

In conclusion, consistent ratios of HBsAg protein and similar particle densities were observed among different phases of infection. In contrast to HBeAg-positive genomes, HBeAg-negative genomes are characterized by an intranuclear localization of assembled/dimeric core protein and a perinuclear accumulation of HBsAg in vitro. This might affect novel antiviral strategies.

 

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Artikel online veröffentlicht:
26. Januar 2022