title: Identification of a B-cell antigenic epitope at the N-terminus of SARS-CoV M protein and characterization of monoclonal antibody against the protein.
abstract: To identify the potential B-cell antigenic epitopes within the N-terminus of SARS-CoV (SARS-associated coronavirus, SARS-CoV) M protein and characterize monoclonal antibody (MAb) against the protein as well as its recognizing region, we expressed and purified a portion of SARS-CoV M protein (amino acid 1-43) in Escherichia coli (E. coli). By using Western blot and enzyme-linked immunosorbent assay (ELISA), we showed that the purified recombinant M protein could be recognized by four SARS-CoV-positive human sera even when those sera were 12,800-fold diluted. Furthermore, we characterized one representative IgG2 MAb, 3H9, which exhibited a strong immunoreaction to both recombinant M protein and native viral protein of SARS-CoV. We found a B-cell antigenic epitope located between amino acid 1-15 and defined the MAb recognizing region within amino acid 16-28 of M. These findings not only suggest that both recombinant M protein and its specific MAbs may be used as the diagnostic reagents for SARS, but also provide a potential target site for the design of an epitope-based vaccine against SARS.
authors.affiliation: The Laboratory of Molecular Virology, Department of Microbiology and Immunology, Jiangsu Province Laboratory of Pathogen Biology, Nanjing Medical University, Nanjing , 210029, PR China.
authors.forename: Chao
authors.initials: C
authors.lastname: Qian
authors.forename: Di
authors.initials: D
authors.lastname: Qin
authors.forename: Qiao
authors.initials: Q
authors.lastname: Tang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zeng
authors.forename: Guixia
authors.initials: G
authors.lastname: Tang
authors.forename: Chun
authors.initials: C
authors.lastname: Lu
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology; D015153:Blotting, Western; D000086862:Coronavirus M Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000302:isolation & purification; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis / Q000276:immunology / Q000821:virology*; D014763:Viral Matrix Proteins / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D000086862:Coronavirus M Proteins; D018985:Epitopes, B-Lymphocyte; C000706237:M protein, SARS-CoV; D011993:Recombinant Fusion Proteins; D014763:Viral Matrix Proteins