Analysis of complete nucleotide sequences of Angolan hepatitis B virus isolates reveals the existence of a separate lineage within genotype E

• Published in: PloS one Vol. 9; no. 3; p. e92223
• Main Authors: Lago, Barbara V, Mello, Francisco C, Ribas, Flavia S, Valente, Fatima, Soares, Caroline C, Niel, Christian, Gomes, Selma A
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.03.2014; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Amino acids; Antigenic determinants; Antigens; Antigens, Surface - genetics; Base Sequence; Bayesian analysis; Biology and life sciences; Cell surface; Cladistic analysis; Conditional probability; Deoxyribonucleic acid; DNA; DNA-Directed DNA Polymerase - genetics; Epitopes; Genetic aspects; Genetic Variation; Genomes; Genotype; Genotype & phenotype; Genotypes; HBX protein; Hepatitis; Hepatitis B; Hepatitis B surface antigen; Hepatitis B virus; Hepatitis B virus - classification; Hepatitis B virus - genetics; Hepatitis B virus - isolation & purification; Humans; Infections; Laboratories; Lymphocytes T; Male; Medicine and health sciences; Middle Aged; Molecular Sequence Data; Mutation; Nucleotides - genetics; Phylogenetics; Phylogeny; Proteins; Virology; Viruses; Young Adult
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0092223

Hepatitis B virus genotype E (HBV/E) is highly prevalent in Western Africa. In this work, 30 HBV/E isolates from HBsAg positive Angolans (staff and visitors of a private hospital in Luanda) were genetically characterized: 16 of them were completely sequenced and the pre-S/S sequences of the remaining 14 were determined. A high proportion (12/30, 40%) of subjects tested positive for both HBsAg and anti-HBs markers. Deduced amino acid sequences revealed the existence of specific substitutions and deletions in the B- and T-cell epitopes of the surface antigen (pre-S1- and pre-S2 regions) of the virus isolates derived from 8/12 individuals with concurrent HBsAg/anti-HBs. Phylogenetic analysis performed with 231 HBV/E full-length sequences, including 16 from this study, showed that all isolates from Angola, Namibia and the Democratic Republic of Congo (n = 28) clustered in a separate lineage, divergent from the HBV/E isolates from nine other African countries, namely Cameroon, Central African Republic, Côte d'Ivoire, Ghana, Guinea, Madagascar, Niger, Nigeria and Sudan, with a Bayesian posterior probability of 1. Five specific mutations, namely small S protein T57I, polymerase Q177H, G245W and M612L, and X protein V30L, were observed in 79-96% of the isolates of the separate lineage, compared to a frequency of 0-12% among the other HBV/E African isolates.