Molecular characterization of a new variant of hepatitis b virus in a persistently infected homosexual man
Article first published online: 6 DEC 2005
Copyright © 1990 American Association for the Study of Liver Diseases
Volume 11, Issue 2, pages 271–276, February 1990
How to Cite
Bhat, R. A., Ulrich, P. P. and Vyas, G. N. (1990), Molecular characterization of a new variant of hepatitis b virus in a persistently infected homosexual man. Hepatology, 11: 271–276. doi: 10.1002/hep.1840110218
- Issue published online: 6 DEC 2005
- Article first published online: 6 DEC 2005
- Manuscript Accepted: 28 AUG 1989
- Manuscript Received: 2 JUN 1989
- National Hurt, Lung and Blood Institute. Grant Number: PO1 HL-36589
Based on the diversity of nucleotide sequences of cloned hepatitis B virus DNA genomes, we have predicted possible replication of genetic variants of human hepatitis B virus. This prediction is exemplified by studies of a chronic carrier of HBsAg/adw2, who lacked anti-HBc but carried exceedingly high levels of hepatitis B virus DNA in serum. Molecular characterization of a number of clones revealed a restriction map that deviated significantly from the typical pattern of the adw2 subtype, especially around the EcoRI site commonly used as a reference point. Mutations appearing consistently in the precore and core regions included (a) mutation in the precore region resulting in a termination codon after the initiation codon, (b) mutation of the core initiation codon and (c) an inframe insert of 36 nucleotides in the precore region with a new initiation site for the core protein.
The 36-nucleotide insertion resulted in a new core protein with 12 extra amino acids at its amino-terminal end. A few scattered point mutations were clustered in the amino-terminal half of the core gene. Although the core protein of this hepatitis B virus variant carried immunologically detectable HBcAg, the absence of a humoral immune response to HBcAg could have been caused by previous infection with human immunodeficiency virus. This naturally occurring human hepatitis B virus variant replicated efficiently without expressing the precore region, confirming previous observations made of the artificial mutants of duck hepatitis B virus.