Hepatitis B virus S gene mutants in infants infected despite immunoprophylaxis

Keywords: hepatitis B virus; S gene mutant; hepatitis B vaccine乙型肝炎疫苗免疫失败儿童S基因变异株研究朱启吕晴俞蕙段恕诚熊思东
From: Chinese Medical Journal 2001;114(4):352-354
CountryChina
Language:Chinese
Abstract: Objective To assess the correlation between hepatitis B virus(HBV) surface gene mutant infection and hepatitis B (HB) vaccination failure. Methods Using sera from 106 infants who were born to HBV carrier mothers and failed in HB immunoprophylaxis, HBV S gene was amplified by PCR, transferred to nylon membranes for Southern blots, and then hybridized with oligonucleotide probes. Eleven of non-hybridizing samples were used for DNA sequencing. Results 93.4% (99/106) of the samples were HBV DNA positive, and 30.3% (30/99) failed to hybridize with at least one of the four probes. DNA sequencing confirmed that 10 of the 11 samples had an S gene mutation with amino acid (aa) change. The identified mutants included nucleotide (nt) 546T→A(aa131N→T), nt531T→C (aa126I→T), nt491A→C (aa113T→P), nt491T→A (aa113S→T), nt533C→A (aa127P→T), nt581T→A (aa143S→T), nt636A→T (aa161Y→F), and nt679A→C (aa175L→F). The sequence in one mother-infant pair was completely the same, with mutations at aa131 and aa161. Conclusions The prevalence of HBV surface mutants is about 30% in the children failing in HB vaccination. HBV mutants can infect infants by maternal-infant transmission.