title: Distinct quasispecies characteristics and positive selection within the core gene in chronic hepatitis B virus infected child and adult patients.
abstract: There are significant differences in clinical characteristics between chronic hepatitis B virus infected (CHB) child and adult patients. Viral quasispecies characteristics are associated with its pathogenic properties. For hepatitis B virus (HBV), its core region is the main immune recognition region for its enriched epitopes. In our study, we discuss the quasispecies characteristics and positive selection within core gene within chronic HBV infected child and adult patients. By analyzing 170 core gene sequences from child CHB patients and 121 core genes sequences from adult CHB patients, quasispecies characteristics were described by sequence complexity, diversity, non-synonymous substitution ratio (dN) and synonymous substitution ratios (dS). In addition, positive selection sites were also determined by bioinformatics tools. Then, all these parameters were compared between child and adult CHB patient groups. Compared with child patients, adult patients with CHB showed distinct quasispecies characteristics within the core region, had a higher sequence complexity and diversity and more positive selection sites, suggesting that the adult CHB patients had a higher immune selection pressure on the HBV core gene. Reduced selection pressure on the HBV core gene in hepatitis B e antigen (HBeAg)-positive CHB patients than HBeAg negative CHB patients were observed in both adult and child patient groups. The majority of the screened positive selection sites lay within human leukocyte antigens (HLA)-restricted epitopes. In conclusion, this study analyzed the quasispecies characteristics discrepancy between child and adult patients with CHB, and revealed the possible reason for the distinct clinical characteristics in the perspective of population genetics.
authors.affiliation: The Key Laboratory of Molecular Biology of Infectious Diseases of the Chinese Ministry of Education, Chongqing Medical University, Yuzhong 400016, China.
authors.forename: Hai-jun
authors.initials: HJ
authors.lastname: Deng
authors.affiliation: 1. The Key Laboratory of Molecular Biology of Infectious Diseases of the Chinese Ministry of Education, Chongqing Medical University, Yuzhong 400016, China; 2. The Department of clinical laboratory, The Second Affiliated Hospital of Chongqing Medical University, Yuzhong 400010, China;
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.affiliation: The Key Laboratory of Molecular Biology of Infectious Diseases of the Chinese Ministry of Education, Chongqing Medical University, Yuzhong 400016, China.
authors.forename: Ai-long
authors.initials: AL
authors.lastname: Huang
authors.affiliation: The Key Laboratory of Molecular Biology of Infectious Diseases of the Chinese Ministry of Education, Chongqing Medical University, Yuzhong 400016, China.
authors.forename: Quan-xin
authors.initials: QX
authors.lastname: Long
mesh_terms: D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D014644:Genetic Variation; D006513:Hepatitis B e Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012641:Selection, Genetic
chemical_list: D006513:Hepatitis B e Antigens