Detection of hepatitis B virus precore stop codon mutants by selective amplification method: Frequent detection of precore mutants in hepatitis B e antigen positive healthy carriers
Version of Record online: 28 JUN 2008
Journal of Gastroenterology and Hepatology
Volume 10, Issue 4, pages 419–425, August 1995
How to Cite
NAKAHORI, S., YOKOSUKA, O., EHATA, T., CHUANG, W.-L., IMAZEKI, F., ITO, Y. and OHTO, M. (1995), Detection of hepatitis B virus precore stop codon mutants by selective amplification method: Frequent detection of precore mutants in hepatitis B e antigen positive healthy carriers. Journal of Gastroenterology and Hepatology, 10: 419–425. doi: 10.1111/j.1440-1746.1995.tb01594.x
- Issue online: 28 JUN 2008
- Version of Record online: 28 JUN 2008
- Accepted for publication 19 September 1994.
- hepatitis B virus;
- polymerase chain reaction;
- precore region
The precore region of hepatitis B virus (HBV) is indispensable for secretion of e antigen protein. Therefore, the precore stop codon mutants may play an important role in the process of e antigen seroconversion. However, the presence of the mutants in hepatitis B e antigen positive carriers has not been fully studied because of difficulties in detecting the mutants in the presence of large amounts of wild-type viruses. To overcome this, a sensitive method has been developed to detect the presence of G to A stop codon mutants at codon 28 of precore region. Primers for polymerase chain reaction (PCR) were devised to introduce restriction enzyme site Sty I for wild-type viruses and Dde I for the mutants. The amplification products with these primers were digested with Sty I to exclude the products from wild-type viruses. The remaining amplicon from precore mutants were re-amplified, and the presence of precore mutant was confirmed with Dde I digestion. The presence of precore mutants was examined in 61 HBV carriers by the method combining PCR and restriction enzyme digestion. Approximately 0.1% of precore mutant DNA among 106 copies of wild-type virus DNA was detectable by this method. The presence of the precore mutants was detected in seven of 10 (70%) e antigen positive asymptomatic carriers, and in 29 of 36 (81%) e antigen positive patients with chronic liver diseases, and in all 15 (100%) anti-e antibody positive patients with chronic liver diseases.
This study revealed that a small amount of the precore mutants was present in the majority of HBV carriers.