title: Five subgenotypes of hepatitis B virus genotype B with distinct geographic and virological characteristics.
abstract: Several hepatitis B virus (HBV) subgenotypes, HBV/A1, A2, Bj and Ba, have been reported with respect to clinical differences among patients infected with these subgenotypes. The population genetics and phylogeography of HBV were investigated based on the complete genome sequences of 484 isolates with 108 from our chronic hepatitis B patients and the remaining from the GenBank database. Besides genotypes A-H (HBV/A-H), five subgenotypes were identified among 169 HBV/B isolates by phylogenetic analysis and nucleotide divergence. There were 27 isolates of subgenotype B(1) (HBV/B(1)) restricted to Japan, 104 isolates of HBV/B(2) with the widest distribution in most Asian countries, 4 isolates of HBV/B(3) restricted to Indonesia, 32 isolates of HBV/B(4) restricted to Vietnam, and 7 isolates of HBV/B(5) restricted to Philippines. HBV/B(2)-B(5) isolates carried a recombination with HBV/C over the precore and core genes. In addition to the characteristics of HBV/B(1)-B(5) at some cis-acting elements, the precore stop-codon mutant (G1896A) was significantly different among HBV/B(1), HBV/B(2), and HBV/B(4) (70.3%, 31.7%, 53.0%, P=0.001), while no such mutation was found in HBV/B(3) and B(5). Among characteristics of the HBV/B(1)-B(5) amino acid sequences, serotype adw (K(122)) was exclusive among HBV/B(1), HBV/B(2), and HB V/B(3) isolates, while serotype ayw (R(122)) was among the HBV/B(4) and HBV/B(5) isolates. Furthermore, distinct variations of T cell and B cell recognition epitopes within surface and core proteins were also found among these subgenotypes. In conclusion, subgenotypes HBV/B(1)-B(5) exhibited distinct geographical distributions, virologic characteristics, and probable clinical implications.
authors.affiliation: Institute of Basic Medical Sciences, Medical College, National Cheng Kung University, Tainan, Taiwan, ROC.
authors.forename: Wen-Chun
authors.initials: WC
authors.lastname: Liu
authors.forename: Pham Hoang
authors.initials: PH
authors.lastname: Phiet
authors.forename: Tzen-Yuh
authors.initials: TY
authors.lastname: Chiang
authors.forename: Koun-Tem
authors.initials: KT
authors.lastname: Sun
authors.forename: Kuo-Hsiang
authors.initials: KH
authors.lastname: Hung
authors.forename: Kung-Chia
authors.initials: KC
authors.lastname: Young
authors.forename: I-Chin
authors.initials: IC
authors.lastname: Wu
authors.forename: Pin-Nan
authors.initials: PN
authors.lastname: Cheng
authors.forename: Ting-Tsung
authors.initials: TT
authors.lastname: Chang
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D014644:Genetic Variation; D016679:Genome, Viral; D005838:Genotype; D016174:Hepacivirus / Q000235:genetics; D006515:Hepatitis B virus / Q000145:classification* / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics