title: Cloning and expression of surface antigens from occult chronic hepatitis B virus infections and their recognition by commercial detection assays.
abstract: Occult hepatitis B virus (HBV) infections show little or no serological markers of viral infection, including the absence of hepatitis B surface antigen (HBsAg) which is the main marker of ongoing HBV infection. Such infections can be important in the context of blood and/or organ donations. To study whether mutations contribute to HBsAg seronegativity, S gene sequences from such patients were amplified and cloned. Sequencing revealed 12 clones from seven different patients which contained potentially important mutations. The sequences were subcloned into an expression vector and mutant HBsAgs were expressed in cell culture. The capacity of three HBsAg detection assays to recognise the mutant HBsAgs was studied. Three categories were found: mutant HBsAgs that are not recognised by the assays, those that are recognised as well as wild-type (WT) antigen and an intermediate category where detection of the mutant HBsAgs is reduced with respect to WT. Most of the isolates fall into the second category. Mutations can therefore contribute to HBsAg seronegativity in occult HBV infections, but in most cases the explanation is probably the low level of viral replication.
authors.affiliation: U271 INSERM, Lyon, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Jeantet
authors.forename: Isabelle
authors.initials: I
authors.lastname: Chemin
authors.forename: Bernard
authors.initials: B
authors.lastname: Mandrand
authors.forename: Albert
authors.initials: A
authors.lastname: Tran
authors.forename: Fabien
authors.initials: F
authors.lastname: Zoulim
authors.forename: Philippe
authors.initials: P
authors.lastname: Merle
authors.forename: Christian
authors.initials: C
authors.lastname: Trepo
authors.forename: Alan
authors.initials: A
authors.lastname: Kay
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000097:blood; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000821:virology*; D022781:Hepatocytes / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation; D011933:Reagent Kits, Diagnostic; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D011933:Reagent Kits, Diagnostic