title: Discovery of a Novel Mutation (X8Del) Resulting in an 8-bp Deletion in the Hepatitis B Virus X Gene Associated with Occult Infection in Korean Vaccinated Individuals.
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.
authors.affiliation: Department of Microbiology and Immunology, Liver Research Institute, Cancer Research Institute and SNUMRC, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Hong
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Microbiology and Immunology, Liver Research Institute, Cancer Research Institute and SNUMRC, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Jeong-Ryeol
authors.initials: JR
authors.lastname: Gong
authors.affiliation: Department of Microbiology and Immunology, Liver Research Institute, Cancer Research Institute and SNUMRC, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Seoung-Ae
authors.initials: SA
authors.lastname: Lee
authors.affiliation: Department of Microbiology and Immunology, Liver Research Institute, Cancer Research Institute and SNUMRC, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Bum-Joon
authors.initials: BJ
authors.lastname: Kim
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D058070:Asymptomatic Diseases; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics; D005260:Female; D016679:Genome, Viral; D006509:Hepatitis B / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000502:physiology; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D009154:Mutation; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D015995:Prevalence; D056910:Republic of Korea; D016415:Sequence Alignment; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics* / Q000502:physiology; D014162:Transfection; D014611:Vaccination; D054334:Viral Regulatory and Accessory Proteins; D014771:Virion; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D006513:Hepatitis B e Antigens; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D000410:Alanine Transaminase