title: Monoclonal antibodies targeting the HR2 domain and the region immediately upstream of the HR2 of the S protein neutralize in vitro infection of severe acute respiratory syndrome coronavirus.
abstract: We have previously shown that an Escherichia coli-expressed, denatured spike (S) protein fragment of the severe acute respiratory coronavirus, containing residues 1029 to 1192 which include the heptad repeat 2 (HR2) domain, was able to induce neutralizing polyclonal antibodies (C. T. Keng, A. Zhang, S. Shen, K. M. Lip, B. C. Fielding, T. H. Tan, C. F. Chou, C. B. Loh, S. Wang, J. Fu, X. Yang, S. G. Lim, W. Hong, and Y. J. Tan, J. Virol. 79:3289-3296, 2005). In this study, monoclonal antibodies (MAbs) were raised against this fragment to identify the linear neutralizing epitopes in the functional domain and to investigate the mechanisms involved in neutralization. Eighteen hybridomas secreting the S protein-specific MAbs were obtained. Binding sites of these MAbs were mapped to four linear epitopes. Two of them were located within the HR2 region and two immediately upstream of the HR2 domain. MAbs targeting these epitopes showed in vitro neutralizing activities and were able to inhibit cell-cell membrane fusion. These results provide evidence of novel neutralizing epitopes that are located in the HR2 domain and the spacer region immediately upstream of the HR2 of the S protein.
authors.affiliation: Institute of Molecular and Cell Biology, Proteos, 61 Biopolis Drive, Singapore 138673.
authors.forename: Kuo-Ming
authors.initials: KM
authors.lastname: Lip
authors.forename: Shuo
authors.initials: S
authors.lastname: Shen
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Yang
authors.forename: Choong-Tat
authors.initials: CT
authors.lastname: Keng
authors.forename: Aihua
authors.initials: A
authors.lastname: Zhang
authors.forename: Hsueh-Ling Janice
authors.initials: HL
authors.lastname: Oh
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Li
authors.forename: Le-Ann
authors.initials: LA
authors.lastname: Hwang
authors.forename: Chih-Fong
authors.initials: CF
authors.lastname: Chou
authors.forename: Burtram C
authors.initials: BC
authors.lastname: Fielding
authors.forename: Timothy H P
authors.initials: TH
authors.lastname: Tan
authors.forename: Josef
authors.initials: J
authors.lastname: Mayrhofer
authors.forename: Falko G
authors.initials: FG
authors.lastname: Falkner
authors.forename: Jianlin
authors.initials: J
authors.lastname: Fu
authors.forename: Seng Gee
authors.initials: SG
authors.lastname: Lim
authors.forename: Wanjin
authors.initials: W
authors.lastname: Hong
authors.forename: Yee-Joo
authors.initials: YJ
authors.lastname: Tan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology*; D002460:Cell Line; D000939:Epitopes / Q000276:immunology; D006801:Humans; D008561:Membrane Fusion / Q000276:immunology; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D017434:Protein Structure, Tertiary; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology* / Q000378:metabolism; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology / Q000821:virology*; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000939:Epitopes; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus