title: Generation and characterization of a novel tetravalent bispecific antibody that binds to hepatitis B virus surface antigens.
abstract: Hepatitis B virus (HBV) infection is a worldwide public health problem affecting about 350 million people. HBV envelope contains three surface antigens, called pre-S1, pre-S2 and S. For the prophylaxis of HBV infection, only an anti-S monoclonal antibody was tested for the protective efficacy against HBV infection, but it was shown to be incomplete. In addition, some immune escape mutants carrying mutations on the S antigen were reported. Therefore, a multivalent bispecific antibody rather than a single monoclonal antibody would be more beneficial for the prophylaxis of HBV infection. We have generated a novel tetravalent bispecific antibody with two binding sites for each of the S and pre-S2 antigens. Each of the antigen-binding sites was composed of a single-chain Fv (ScFv). The tetravalent antibody was generated by constructing a single gene encoding a single-chain protein. This protein consisted of an anti-S ScFv whose carboxyl end was tethered, through a 45 amino acid linker, to the amino terminus of anti-preS2 ScFv that in turn was joined to the hinge region of human gamma1 constant region. The single-chain protein was expressed in Chinese hamster ovary cells and secreted in culture supernatant as a homodimeric molecule. The tetravalent bispecific antibody showed both anti-S and anti-pre-S2 binding activities. In addition, the binding affinity of the bispecific antiboy for HBV particles was greater than that of either parental antibody. The tetravalent bispecific antibody is a potentially useful reagent for the prevention and treatment of HBV infection.
authors.affiliation: The Antibody Engineering Research Laboratory, Korea Research Institute of Bioscience and Biotechnology, PO Box 115, Yuseong, Taejon 305-600, South Korea.
authors.forename: S S
authors.initials: SS
authors.lastname: Park
authors.forename: C J
authors.initials: CJ
authors.lastname: Ryu
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kang
authors.forename: S V
authors.initials: SV
authors.lastname: Kashmiri
authors.forename: H J
authors.initials: HJ
authors.lastname: Hong
mesh_terms: D018033:Antibodies, Bispecific / Q000235:genetics* / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology; D000915:Antibody Affinity; D006510:Hepatitis B Antibodies / Q000235:genetics / Q000276:immunology*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D007141:Immunoglobulin Fc Fragments / Q000235:genetics / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology; D008958:Models, Molecular; D011233:Precipitin Tests
chemical_list: D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D007141:Immunoglobulin Fc Fragments; D007135:Immunoglobulin Variable Region