Active hepatitis B virus replication in the presence of anti-HBe is associated with viral variants containing an inactive pre-C region

Abstract

Although rise of anti-HBe immunity in the course of hepatitis B virus (HBV) infection is generally followed by clearance of the infectious virions, ongoing chronic liver disease with circulating virions has been repeatedly observed in a significant number of anti-HBe patients, especially in Mediterranean countries. To investigate the possible role of HBV variants, we cloned HBV DNA from the serum of three such anti-HBe cases. Comparative restriction mapping of HBV clones suggested circulation of different HBV genomes in the three cases. DNA sequencing revealed an inactive pre-C region in all 11 HBV clones derived from the three cases, either as one or two point mutations in the 3' terminus generating an in-frame TAG stop codon, or a 1 nucleotide insertion in the 5' terminus resulting in frameshift mutation. Furthermore, for one clone the complete 3182 nucleotide sequence was determined and no significant mutation was found in the remainder of the genome. We conclude that chronic hepatitis cases positive for anti-HBe are associated with HBV variants containing an inactive pre-C region and hence cannot synthesize pre-C region-derived HBeAg. This finding may provide a molecular explanation for the continued viral replication despite presence of anti-HBe immunity.