Detection of hepatitis B virus isolates with mutations associated with immune escape mutants among pregnant women in Ibadan, southwestern Nigeria.

Temitope Oluwasegun Cephas Faleye,Deborah Oluwaseyi Makanjuola,Johnson Adekunle Adeniji,Moses Olubusuyi Adewumi,Ewean Chukwuma Omoruyi,Funmilola Awokunle,Ijeoma Maryjoy Ifeorah,Hannah Opeyemi Ajibola,Solomon Adeleye Bakarey,Adegboyega Akere

doi:10.1186/s40064-015-0813-1

Temitope Oluwasegun Cephas Faleye, Deborah Oluwaseyi Makanjuola + Show 8 more

Open Access

https://doi.org/10.1186/s40064-015-0813-1

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Journal: SpringerPlus	Publication Date: Feb 1, 2015
Citations: 54	License type: CC BY 4.0

Affiliation: University of Ibadan, Ekiti State University

Abstract

Perinatal transmission of hepatitis B virus (HBV) and its associated immune escape mutants (IEMs), is the major vehicle through which a population of chronically infected people who serve as infectious HBV reservoirs is maintained in communities. Therefore, to assess the risk of perinatal transmission, 272 pregnant women attending ante-natal clinics in Ibadan metropolis, southwestern, Nigeria, were screened for HBsAg using ELISA technique. Samples positive for HBsAg were subjected to HBV DNA detection by PCR amplification of the S-gene and amplicon sequencing. Isolates were genotyped and subtyped using a combination of molecular techniques.Fifteen (5.5%) of the pregnant women were positive for HBsAg of which HBV DNA was detected in seven. Five of the isolates were typed as genotype E subtype ayw4 using amino acid residues at positions 122, 127, 134 and 160. Another could only be typed as genotype E subtype ayw4 by further phylogenetic analysis. The remaining one isolate did not belong to any of genotypes A – H. Three of the HBV isolates including the untypable, had mutations in the ‘a’ determinant associated with IEMs.This study confirms the endemicity of HBV, the risk of perinatal transmission and the circulation of genotype E subtype ayw4 in Nigeria. It further demonstrates the presence of IEMs in Nigeria.

Highlights

Hepatitis B virus (HBV) belongs to the genus orthohepadnavirus in the family Hepadnaviridae
HBsAg Enzyme Linked Immunosorbent Assay (ELISA) screen, DNA extraction and Surface/Pol gene specific Polymerase Chain Reaction A total of 15 (5.5%) of the 272 samples were positive for HBsAg
DNA was extracted from all the 15 samples that were positive for the HBsAg ELISA screen, and subjected to HBsAg specific Polymerase Chain Reaction (PCR)

Summary

Introduction

Hepatitis B virus (HBV) belongs to the genus orthohepadnavirus in the family Hepadnaviridae. HBV is an enveloped virus with a diameter of ~42 nm. Within the core of the virus is a protein-linked, ~3.2 kb DNA genome that is partly double stranded. The HBV genome has four open reading frames (ORFs) (X, S, P and C) with the X and C ORFs partially overlapping the P ORF which has the S ORF within it but in a different reading frame. Genotypes A - H of HBV have been described (Schaefer 2007) with members of a genotype not differing by more than 8% of their genome (Okamoto et al 1988).

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