title: Localization of immunodominant epitopes within the "a" determinant of hepatitis B surface antigen using monoclonal antibodies.
abstract: The common "a" determinant is the major immunodominant region of hepatitis B surface antigen (HBsAg) shared by all serotypes and genotypes of hepatitis B virus (HBV). Antibodies against this region are thought to confer protection against HBV and are essential for viral clearance. Mutations within the "a" determinant may lead to conformational changes in this region, which can affect the binding of neutralizing antibodies. There is an increasing concern about identification and control of mutant viruses which is possible by comprehensive structural investigation of the epitopes located within this region. Anti-HBs monoclonal antibodies (mAbs) against different epitopes of HBsAg are a promising tool to meet this goal. In the present study, 19 anti-HBs mAbs were employed to map epitopes localized within the "a" determinant, using a panel of recombinant mutant HBsAgs. The topology of the epitopes was analyzed by competitive enzyme-linked immunosorbent assay (ELISA). Our results indicate that all of the mAbs seem to recognize epitopes within or in the vicinity of the "a" determinant of HBsAg. Different patterns of binding with mutant forms were observed with different mAbs. Amino acid substitutions at positions 123, 126, 129, 144, and 145 dramatically reduced the reactivity of antibodies with HBsAg. The T123N mutation had the largest impact on antibody binding to HBsAg. The reactivity pattern of our panel of mAbs with mutant forms of HBsAg could have important clinical implications for immunoscreening, diagnosis of HBV infection, design of a new generation of recombinant HB vaccines, and immunoprophylaxis of HBV infection as an alternative to therapy with hepatitis B immune globulin (HBIG).
authors.affiliation: Department of Immunology, School of Public Health, Tehran University of Medical Sciences, PO Box 6446-14155, Tehran, Iran.
authors.forename: Forough
authors.initials: F
authors.lastname: Golsaz-Shirazi
authors.affiliation: Department of Immunology, School of Public Health, Tehran University of Medical Sciences, PO Box 6446-14155, Tehran, Iran.
authors.forename: Hamed
authors.initials: H
authors.lastname: Mohammadi
authors.affiliation: Department of Immunology, School of Public Health, Tehran University of Medical Sciences, PO Box 6446-14155, Tehran, Iran.|Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Shahid Beheshti University, Evin, PO Box 19835-1177, Tehran, Iran.
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Amiri
authors.affiliation: Department of Immunology, School of Public Health, Tehran University of Medical Sciences, PO Box 6446-14155, Tehran, Iran.
authors.forename: Jalal
authors.initials: J
authors.lastname: Khoshnoodi
authors.affiliation: Immunology, Asthma and Allergy Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Gholam Ali
authors.initials: GA
authors.lastname: Kardar
authors.affiliation: Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Shahid Beheshti University, Evin, PO Box 19835-1177, Tehran, Iran.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Jeddi-Tehrani
authors.affiliation: Department of Immunology, School of Public Health, Tehran University of Medical Sciences, PO Box 6446-14155, Tehran, Iran. fshokri@tums.ac.ir.|Monoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Shahid Beheshti University, Evin, PO Box 19835-1177, Tehran, Iran. fshokri@tums.ac.ir.
authors.forename: Fazel
authors.initials: F
authors.lastname: Shokri
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000302:isolation & purification; D000914:Antibodies, Viral / Q000276:immunology* / Q000302:isolation & purification; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D016056:Immunodominant Epitopes / Q000276:immunology*; D008807:Mice, Inbred BALB C
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D006514:Hepatitis B Surface Antigens; D016056:Immunodominant Epitopes