Abstract
Universal infantile hepatitis B virus (HBV) vaccination may lead to an increase in vaccine escape variants, which may pose a threat to the long-term success of massive vaccination. To determine the prevalence of occult infections in Korean vaccinated individuals, 87 vaccinated subjects were screened for the presence of HBV DNA using both the nested PCR protocol and the VERSANT HBV DNA 3.0 assay. The mutation patterns of variants were analyzed in full-length HBV genome sequences. Their HBsAg secretion and replication capacities were investigated using both in vitro transient transfection and in vivo hydrodynamic injection. The presence of HBV DNA was confirmed in 6 subjects (6.9%). All six variants had a common mutation type (X8Del) composed of an 8-bp deletion in the C-terminal region of the HBV X gene (HBxAg). Our in vitro and in vivo analyses using the full-length HBV genome indicated that the X8Del HBxAg variant reduced the secretion of HBsAg and HBV virions compared to the wild type. In conclusion, our data suggest that a novel mutation (X8Del) may contribute to occult HBV infection in Korean vaccinated individuals via a reduced secretion of HBsAg and virions, possibly by compromising HBxAg's transacting capacity.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adult
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Alanine Transaminase / blood
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Animals
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Asymptomatic Diseases
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Cell Line
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DNA, Viral / genetics
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Female
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Genome, Viral
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Hepatitis B / epidemiology
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Hepatitis B / prevention & control
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Hepatitis B / transmission
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Hepatitis B / virology*
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Hepatitis B Surface Antigens / blood
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Hepatitis B Surface Antigens / physiology
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Hepatitis B Vaccines / immunology*
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Hepatitis B e Antigens / blood
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Hepatitis B virus / genetics*
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Hepatitis B virus / isolation & purification
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Humans
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Male
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Mice
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Mice, Inbred C57BL
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Middle Aged
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Mutation
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Phylogeny
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Polymerase Chain Reaction / methods
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Prevalence
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Republic of Korea
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Sequence Alignment
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Sequence Deletion
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Trans-Activators / genetics*
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Trans-Activators / physiology
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Transfection
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Vaccination*
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Viral Regulatory and Accessory Proteins
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Virion
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Virus Replication
Substances
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DNA, Viral
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Hepatitis B Surface Antigens
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Hepatitis B Vaccines
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Hepatitis B e Antigens
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Trans-Activators
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Viral Regulatory and Accessory Proteins
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hepatitis B virus X protein
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Alanine Transaminase
Grants and funding
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2013-005810). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.