Antigenic and structural relationships of the surface antigens of hepatitis B virus, ground squirrel hepatitis virus, and woodchuck hepatitis virus

Abstract

The surface antigens of human hepatitis B (HBsAg), ground squirrel hepatitis (GSHsAg), and woodchuck hepatitis (WHsAg) viruses were compared serologically, and their major polypeptides were analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis and tryptic peptide mapping. Results showed that both GSHsAg and WHsAg are antigenically cross-reactive, that their major pairs of polypeptides have identical mobilities on sodium dodecyl sulfate gels, and that the major polypeptides of GSHsAg and WHsAg migrate faster in sodium dodecyl sulfate-polyacrylamide gel electrophoresis than do the corresponding bands of HBsAg. The peptide maps of the major (P-22) surface antigen polypeptides of GSHsAg and WHsAg showed that they shared over half of their spots. Peptide mapping of HBsAg subtypes indicated a close relationship between the major polypeptides (P-24) of adw and adr and a more distal relationship to ayw. Only about 25% of the spots shared by the combined HBsAg subtypes were also found in the peptide maps of GSHsAg and WHsAg, indicating at least some structural homology among the major polypeptides of the human and animal virus surface antigen particles. This is also reflected in the serological crossreactivity among HBsAg, GSHsAg, and WHsAg. Further, the detection of ground squirrel and woodchuck antigens by Ausria II radioimmunoassay, combined with peptide mapping data indicating the common origin of these viruses, suggests that the common a determinant is shared by each and is restricted to approximately 25% of the sequences in their major polypeptides.

Core antigen and antibody in woodchucks after infection with woodchuck hepatitis virus

“…Liver biopsies were not available for observation, and the lack of detectable surface antigenemia and of increased serum enzymes suggested that the animal experienced a subclinical infection. Although cross-reactivities between the major antigen-antibody systems of WHV and HBV have been reported (7,8,11,13,33), we did not detect cross-reactive antibodies in this chimpanzee when we used the commercial HBV RIA systems. The antibody responses of the chimpanzee, detected by the present woodchuckspecific RIAs (25,34; Ponzetto et al, submitted for publication), indicated that the responses were specific for WHV infection.…”

“…The eastern woodchuck and the woodchuck hepatitis virus (WHV) are currently under investigation as a naturally occurring model system for hepatitis B virus (HBV) infection in humans. Both WHV and HBV are characterized by similar structural and genomic compositions (9,11,12,28,29), and infection with either virus can lead to analogous pathology in their respective hosts (22,26,27,29,30,31). An important marker for the study of HBV infection in humans has been the detection of viral core antigen in liver biopsies (1,5,35).…”

Molecular characterization and functional analysis of occult hepatitis B virus infection in Chinese patients infected with genotype C

“…Substitutions within the major hydrophilic region of HBsAg (aa 104-172) were found in most patients (one or two amino acids per patient), except patients S4 and S8 (Table II). The immunodominant a determinant (aa 124-147) [Feitelson et al, 1981] of HBsAg had no variation in any of the isolates, except variants S2.2 (A128V), S 2.3 (I126T), and S4.4 (I126T), all the substitutions were within the first hydrophilic loop of the a determinant (Table II). The stop codon mutations in variant S1.1, S7.4, and S8.1 were observed in the coding sequence of HBsAg.…”

Products of the “x” gene in hepatitis B and related viruses

“…Hepatitis B virus (HBV), ground squirrel hepatitis virus (GSHV), woodchuck hepatitis virus (WHV) and duck hepatitis B virus (DHBV) comprise a group of infectious agents which share many biochemical characteristics (1)(2)(3)(4)(5)(6). The virions of each are surrounded by an envelope of surface antigen reactive determinants which are immunologically distinct and which reside on a family of virus-encoded polypeptides whose number and sizes vary (2)(3)(4)(6)(7)(8)(9). Virus nucleocapsids, or core particles, have been isolated by treatment of serumderived virions with nonionic detergent or directly from viruses is circular, heat linearization demonstrates that even after the DNAp reaction, a nick exists in each of the DNA strands (6,19).…”