A NOVEL METHOD FOR EFFICIENT AMPLIFICATION OF WHOLE HEPATITIS-B VIRUSGENOMES PERMITS RAPID FUNCTIONAL-ANALYSIS AND REVEALS DELETION MUTANTS IN IMMUNOSUPPRESSED PATIENTS

Current knowledge of hepatitis B virus (HBV) sequence heterogeneity is based mainly on sequencing of amplified subgenomic HBV fragments, Her e, we describe a method which allows sensitive amplification and simpl ified functional analysis of full-length HBV genomes with or without p rior cloning. By this method, a large number of HBV genomes were clone d from sera of six immunosuppressed kidney transplant patients, Two si ze classes of HBV genomes, one 3.2 kb and another about 2.0 kb id size , were found in all patients. The genome population from one serum sam ple was studied in detail by size analysis of subgenomic PCR fragments and sequencing. Regions with deletions and insertions were mapped in the C gene and pre-S region, UP to 100% of HBV genomes in all other im munosuppressed patients also had deletions in the C gene, Our results demonstrate the potential Of the established method for the structural and functional characterization of heterogeneous populations of compl ete virion-encapsidated HBV DNAs and suggest that HBV genomes with C g ene deletions can have a selective advantage in immunosuppressed patie nts.