Hepatitis B virus S gene mutants in infants infected despite immunoprophylaxis.
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 (aa1261-->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.
Zhu
Q
Q
Department of Infectious Diseases, Children's Hospital, Medical Center of Fudan University, Shanghai 200032, China.
Lu
Q
Q
Xiong
S
S
Yu
H
H
Duan
S
S
D004279:DNA, Viral / Q000097:blood; D005260:Female; D006509:Hepatitis B / Q000517:prevention & control / Q000821:virology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D014611:Vaccination; D014759:Viral Envelope Proteins / Q000235:genetics*
D004279:DNA, Viral; D017325:Hepatitis B Vaccines; C118669:S envelope protein, hepatitis B virus; D014759:Viral Envelope Proteins