1. Evolution of hepatitis B genotype C viral quasi-species during hepatitis B e antigen seroconversion
- Author
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Tatsuo Kanda, Osamu Yokosuka, Kenichi Fukai, Makoto Arai, Fuat Kurbanov, Yutaka Yonemitsu, Yasuhito Tanaka, Masashi Mizokami, Fumio Imazeki, and Shuang Wu
- Subjects
Adult ,Male ,Hepatitis B virus ,HBsAg ,Genotype ,Biology ,medicine.disease_cause ,Evolution, Molecular ,Young Adult ,Hepatitis B, Chronic ,medicine ,Humans ,Point Mutation ,Hepatitis B e Antigens ,Hepatitis B Antibodies ,Seroconversion ,Promoter Regions, Genetic ,Phylogeny ,DNA Primers ,Base Sequence ,Hepatology ,Genetic Variation ,Middle Aged ,Viral Load ,Hepatitis B ,medicine.disease ,Virology ,HBeAg ,DNA, Viral ,Immunology ,Female ,Viral disease ,Viral load - Abstract
Background & Aims Although the evolution of viral quasi-species may be related to the pathological status of disease, little is known about this phenomenon in hepatitis B, particularly with respect to hepatitis B e antigen (HBeAg) seroconversion. Methods Nucleotide sequences of the hepatitis B virus (HBV) X / precore/core region was analyzed at five time-points in four groups of chronic hepatitis B patients, interferon-induced seroconverters (IS, N =9), interferon non-responders (IN, N =9), spontaneous seroconverters (SS, N =9), and non-seroconverters (SN, N =9) followed during 60months on an average. Only patients with genotype C were studied. Results Analysis of 1800 nucleotide sequences showed that there was no statistical difference between the nucleotide genetic distances of seroconverters (IS and SS; 6.9×10 −3 substitutions (st)/site and 6.7×10 −3 st/site, respectively) and those of non-seroconverters (IN and SN; 5.3×10 −3 st/site and 3.8×10 −3 st/site, respectively) before seroconversion. Compared to non-seroconverters (IN and SN; 5.1×10 −3 st/site and 5.9×10 −3 st/site, respectively), the sequence diversity of seroconverters (IS and SS; 10.9×10 −3 st/site and 9.9×10 −3 st/site, respectively) was significantly higher after seroconversion ( p 0.05), and was higher in seroconverters after seroconversion than before seroconversion ( p 0.05), while this changed very little in non-seroconverters during the observation period. Phylogenetic trees showed greater complexity in secoconverters than non-seroconverters. Parsimony-based estimation of the direction of sequence change between descendants and ancestors before HBeAg seroconversion, revealed higher frequencies of transversional A to T substitution in seroconverters (0.06 vs . 0.02, p =0.0036) that coincided with the dynamics of quasi-species possessing A1762T mutation. Conclusions The distinctly greater viral diversity in HBeAg seroconverters after seroconversion could be related to escape mutants resulting from stronger selection pressure.
- Published
- 2011