Virologic characteristics of hepatitis B virus in patients infected via maternal-fetal transmission.
OBJECTIVE
To determine whether HBV with the same characteristics causes dissimilar mutations in different hosts.


METHODS
Full-length HBV genome was amplified and linked with pMD T18 vector. Positive clones were selected by double-restriction endonuclease digestion (EcoRI and HindIII) and PCR. Twenty seven clones were randomly selected from an asymptomatic mother [at two time points: 602 (1 d) and 6022 (6 mo)] and her son [602 (S)], and the phylogenetic and mutational analysis was performed using BioEditor, Clustal X and MEGA software. Potential immune epitopes were determined by the Stabilized Matrix Method (SMM), SMM-Align Method and Emini Surface Accessibility Prediction.


RESULTS
All of the 27 sequences were genotype C, the divergence between the mother and son was 0%-0.8%. Compared with another 50 complete sequences of genotype C, the mother and her son each had 13 specific nucleotides that differed from the other genotype C isolates. AA 1-11 deletion in preS1 was the dominant mutation in the mother (14/18). The 1762T/1764A double mutation existed in all clones of the mother, 3 of them were also coupled with G1896A mutation, but none were found in the son. 17 bp deletion starting at nucleotide 2330 was the major mutation (5/9) in the son, which caused seven potential HLA class I epitopes and one B cell epitope deletion, and produced a presumptive new start codon, downstream from the original one of the P gene.


CONCLUSIONS
The HBV strain in the son came from his mother, and discrepant mutation occurred in the mother and her son during infection.
Shen
Tao
T
Institute of Basic Medicine of the First People's Hospital of Yunnan Province, Kunming 650032, China.
Yan
Xin-Min
XM
Zou
Yun-Lian
YL
Gao
Jian-Mei
JM
Dong
Hong
H
D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002648:Child; D018387:Codon, Initiator; D004279:DNA, Viral / Q000097:blood*; D000939:Epitopes / Q000235:genetics*; D005260:Female; D005838:Genotype; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000235:genetics*; D006513:Hepatitis B e Antigens / Q000097:blood / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000635:transmission* / Q000821:virology; D006801:Humans; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D013997:Time Factors; D019562:Viral Load
D018387:Codon, Initiator; D004279:DNA, Viral; D000939:Epitopes; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens