Characterization of neutralizing monoclonal antibodies recognizing a 15-residues epitope on the spike protein HR2 region of severe acute respiratory syndrome coronavirus (SARS-CoV)

• Published in: Journal of biomedical science Vol. 12; no. 5; pp. 711 - 727
• Main Authors: Lai, Szu-Chia, Chong, Pele Choi-Sing, Yeh, Chia-Tsui, Liu, Levent Shih-Jen, Jan, Jia-Tsrong, Chi, Hsiang-Yun, Liu, Hwan-Wun, Chen, Ann, Wang, Yeau-Ching
• Format: Journal Article
• Language: English
• Published: England Springer Netherlands 01.10.2005
• Subjects: Amino Acid Sequence; Animals; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - immunology; Base Sequence; Blotting, Western; DNA Primers; Electrophoretic Mobility Shift Assay; Enzyme-Linked Immunosorbent Assay; Epitopes - chemistry; Epitopes - immunology; Escherichia coli; Fluorescent Antibody Technique, Indirect; Membrane Glycoproteins - chemistry; Membrane Glycoproteins - immunology; Mice; Mice, Inbred BALB C; Molecular Sequence Data; Neutralization Tests; SARS coronavirus; SARS Virus - immunology; Spike Glycoprotein, Coronavirus; Viral Envelope Proteins - chemistry; Viral Envelope Proteins - immunology
• ISSN: 1021-7770; 1423-0127
• DOI: 10.1007/s11373-005-9004-3

The spike (S) glycoprotein is thought to play a complex and central role in the biology and pathogenesis of SARS coronavirus infection. In this study, a recombinant protein (rS268, corresponding to residues 268-1255 of SARS-CoV S protein) was expressed in Escherichia coli and was purified to near homogeneity. After immunization with rS268, S protein-specific BALB/c antisera and mAbs were induced and confirmed using ELISA, Western blot and IFA. Several BALB/c mAbs were found to be effectively to neutralize the infection of Vero E6 cells by SARS-CoV in a dose-dependent manner. Systematic epitope mapping showed that all these neutralizing mAbs recognized a 15-residues peptide (CB-119) corresponding to residues 1143-1157 (SPDVDLGDISGINAS) that was located to the second heptad repeat (HR2) region of the SARS-CoV spike protein. The peptide CB-119 could specifically inhibit the interaction of neutralizing mAbs and spike protein in a dose-dependent manner. Further, neutralizing mAbs, but not control mAbs, could specifically interact with CB-119 in a dose-dependent manner. Results implicated that the second heptad repeat region of spike protein could be a good target for vaccine development against SARS-CoV.