Point mutations in the S and pre-S2 genes observed in two hepatitis B virus carriers positive for antibody to hepatitis B surface antigen.
Two hepatitis B virus (HBV) carriers who had antibodies to HBV surface antigen (anti-HBs) were studied. Case 1 was a 47 year old woman positive for hepatitis B e antigen (HBeAg), and case 2 was a 61 year old man positive for antibody to HBeAg (anti-HBe) and DNA-polymerase (DNA-p). Neither case had received the HBV vaccine. The nucleotide sequences of the HBV-DNA extracted from the patients' sera were determined within the pre-S2 and S genes. Seven out of nine S gene clones from case 1 and six out of nine S gene clones from case 2 had an amino acid replacement from Thr or Ile to Ser at codon 126 in the alpha-determinant of the S gene. Amino acid substitution of codon 145 of the S gene previously reported was not observed. Although two previous reports on HBV escape mutant carriers with both anti-HBs and HBeAg described some deletions in the pre-S2 gene, our cases did not show these deletions. Our analysis indicated that carriers with the HBV escape mutant did not always have pre-S2 gene deletions. We found two HBV escape mutant carriers who had amino acid substitutions at codon 126 in the S gene due to point mutation without any deletions in the pre-S2 gene.
Shinji
T
T
First Department of Internal Medicine, Okayama University Medical School, Japan.
Koide
N
N
Hanafusa
T
T
Hada
H
H
Oka
T
T
Takayama
N
N
Shiraha
H
H
Nakamura
M
M
Ujike
K
K
Yumoto
Y
Y
Tsuji
T
T
D004279:DNA, Viral / Q000235:genetics; D005260:Female; D005814:Genes, Viral / Q000235:genetics*; D006509:Hepatitis B / Q000276:immunology / Q000821:virology*; D006510:Hepatitis B Antibodies / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology*; D006513:Hepatitis B e Antigens / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D017354:Point Mutation / Q000235:genetics*; D011498:Protein Precursors / Q000235:genetics*; D014759:Viral Envelope Proteins / Q000235:genetics*
D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens; D011498:Protein Precursors; D014759:Viral Envelope Proteins; C050807:presurface protein 2, hepatitis B surface antigen