Genotype C of hepatitis B virus can be classified into at least two subgroups

Abstract

A genomic characterization of hepatitis B virus (HBV) was done for 56 pre-S1/pre-S2 genes and 10 full-length HBV genotype C isolates from five Asian countries. Phylogenetic analysis of the pre-S1/pre-S2 genes revealed two major groups within genotype C: one for isolates from southeast Asia including Vietnam, Myanmar and Thailand (named HBV/C1) and the other for isolates from Far East Asia including Japan, Korea and China (named HBV/C2). This finding was confirmed by phylogenetic analysis based on the full-length sequence of 32 HBV genotype C isolates, including 22 from database entries. Two isolates from Okinawa, the island off the southern end of Japan, formed a different branch. Specific amino acid sequence changes were identified in the large S protein (amino acids 51, 54, 60, 62 and 73) and P protein (amino acids 231, 233, 236, 248, 252 and 304). Our results indicate that genotype C of HBV can be classified into at least two subgroups. INTRODUCTIONHepatitis B virus (HBV) infection is a global health problem, with more than 350 million people chronically infected worldwide (Lee, 1997). The infection is associated with a wide spectrum of clinical symptoms, ranging from acute or fulminant hepatitis to various forms of chronic liver disease, such as chronic hepatitis, cirrhosis and hepatocellular carcinoma. HBV has been classified into genotypes A-G, with an intergenotypic diversity of at least 8 % in the full genome sequence (Okamoto et al., 1988;Norder et al., 1994). HBV genotypes have a distinct geographical distribution and correlate with severity of liver disease (KiddLjunggren et al., 2002). Genotypes B and C are prevalent in Asia, and genotype C causes more serious liver disease than genotype B (Shiina et al., 1991;Orito et al., 2001). Moreover, HBV strains in the same genotype may differ in their capacity to induce clinical liver disease. Subgroup Ba of genotype B, which is recombinant with genotype C, is found predominantly in southeast Asian countries and appears to have more detrimental effects than subgroup Bj (Sugauchi et al., 2002a). Recently, a novel genotype C variant has been found in Australian aborigines (Sugauchi et al., 2001). Therefore, it is possible that virological differences in HBV genotype C exist in Asian countries resulting in different clinical outcomes for patients. To analyse this further, we carried out genomic characterization of HBV genotype C isolates and found that they could be classified into at least two subgroups. METHODSSource of sera, genotyping and serotyping of HBV. HBV DNA-positive sera were obtained from 56 patients in five different Asian countries: 17 from Vietnam, 21 from Myanmar, four from Thailand, nine from China and five from Japan (three from Tokyo and two from Okinawa). All sera were found to be HBV genotype C by PCR genotyping using type-specific primers as reported previously (Naito et al., 2001). The HBV serotype was inferred from the The DDBJ/GenBank/EMBL accession nos. of sequences reported in this study are HBV-VT101, AB112063; HBV-VT103, AB111946; ...

Hepatitis B Virus Genotype C Isolates with Wild-Type Core Promoter Sequence Replicate Less Efficiently than Genotype B Isolates but Possess Higher Virion Secretion Capacity

“…The B1 subgenotype is found exclusively in Japan, while the B2 subgenotype is prevalent in Taiwan, Hong Kong, and China (36,37,46,49). Genotype C1 is found in Southeast Asia, Hong Kong, and southern China, whereas C2 is distributed in Japan, South Korea, Taiwan, and northern China (4,12). On the basis of sequencing of the core promoter and precore/core gene, the Chinese HBV isolates, all collected in Shanghai, belong to the B2 and C2 subgenotypes.…”

Novel Subgenotypes of Hepatitis B Virus Genotypes C and D in Papua, Indonesia

“…Subgenotypes (subgroups) have been identified for certain HBV genotypes (7,9,15,20,22,26). HBV/C has been classified into five subgenotypes, HBV/C1 to HBV/C5 (7,9,26,30), as has HBV/D, into HBV/D1 to HBV/D5 (3,5,22,28).…”

The rtA181 Mutation Produces Similar Clinical and Cellular Characteristics in Patients infected with Hepatitis B Virus Genotypes B and C

“…NAs act through suppression the virus replication, while interferon acts through boosting the immune response against the virus. HBV genotypes lead to different virulence and pathogenicity, 29 which may induce different immune response in the host. Therefore, patients may have a better effect to interferon that stimulated a more pronounced immune response.…”