Direct detection of HBV preC mutants in heterogeneous viral populations by a modified DNA sequencing method

A modified method for the direct sequencing of double-stranded DNA products of PCR amplification is described and has been applied to the analysis of hepatitis B virus (HBV) preC/C region in samples from persistently infected patients with chronic hepatitis. Data was obtained from both hepatitis B e antigen (HBeAg)-positive and -negative chronic carriers. A high prevalence of mixed viral populations (wild-type genomes and mutated sequences with a TAG stop codon in the distal preC region at position 1895-1897) was shown in the HBeAg-positive group; a homogeneous (either mutated or wild-type) viral population was detected in all but one of the long-term HBeAg-negative, untreated chronic carriers, thus suggesting that pre-core mutants can be rapidly generated and selected during the natural course of HBV infection.