High conservation of hepatitis B virus surface genes during maternal vertical transmission despite active and passive vaccination.
OBJECTIVE
Our purpose was to explore the relationship between hepatitis B virus (HBV) gene heterogeneity and maternal vertical transmission.


METHODS
HBsAg-positive mothers and their neonates were selected and classified into a vertical infection neonate group (group N), a vertical infection mother group (group M) and a control group (group C). Serum HBsAg and HBeAg were examined. HBV gene fragments, including the pre-S1, and pre-S2 and S coding regions, were amplified and sequenced, and the genotype and serotype of the sequences were identified. Mutation sites and frequency of mutations were then compared between group N and group C.


RESULTS
A total of 104 HBV clone sequences were obtained. All obtained sequences belonged to genotype C and serotype adr. Upon comparing sequences between group N and group C, 4 nonsynonymous mutations were found with significant difference in mutation frequency (p < 0.05). When the mothers were both HBsAg and HBeAg positive, 10 nonsynonymous mutations were found. The frequencies of these mutations were significantly lower in group N than in group C (p < 0.05).


CONCLUSIONS
The 10 HBV mutations were negatively associated with vertical transmission when maternal HBeAg was positive. Furthermore, the species that were vertically transmitted to the fetus were mainly wild-type.
Department of Epidemiology, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an, China.
Hai-Xia
HX
Su
Yu-Hai
YH
Zhang
Zhi-Guo
ZG
Zhang
Duan
D
Li
Jing-Xia
JX
Zhang
Ke
K
Men
Lei
L
Zhang
Yong
Y
Long
De-Zhong
DZ
Xu
Yong-Ping
YP
Yan
D000328:Adult; D019943:Amino Acid Substitution / Q000235:genetics; D017124:Conserved Sequence; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D005260:Female; D006509:Hepatitis B / Q000635:transmission* / Q000821:virology*; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000235:genetics; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D020125:Mutation, Missense; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011498:Protein Precursors / Q000235:genetics; D017422:Sequence Analysis, DNA
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D006513:Hepatitis B e Antigens; D011498:Protein Precursors; C050806:presurface protein 1, hepatitis B surface antigen; C050807:presurface protein 2, hepatitis B surface antigen