Identification of two antigenic epitopes on SARS-CoV spike protein

Abstract

The spike (S) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a major virion structural protein. It plays an important role in interaction with receptor and inducing neutralizing antibodies. In the study, six tentative antigenic epitopes (S1 S2 S3 S4 S5 S6) of the spike protein of SARS-CoV were predicted by bio-informatics analysis, and a multi-epitope chimeric gene of S1-S2-S3-S4-S5-S6 was synthesized and fused to downstream GST gene in pGEX-6p-1. The Western blotting demonstrated that SARS patient convalescent serum could recognize the recombinant fusion protein. A number of monoclonal antibodies were developed against the fusion protein. In further, the six predicted epitope genes were individually fused to GST of pGEX-6p-1 and expressed in Escherichia coli BL21, respectively. Among six fusion peptides, S5 reacted with monoclonal antibody D3C5 and S2 reacted with monoclonal antibody D3D1 against spike protein of SARS-CoV. The epitopes recognized by monoclonal antibodies D3C5 and D3D1 are linear, and correspond to 447-458 and 789-799 amino acids of spike protein of SARS-CoV, respectively. Identification of antigenic epitope of spike protein of SARS-CoV could provide the basis for the development of immunity-based prophylactic, therapeutic, and diagnostic techniques for the control of severe acute respiratory syndrome.

Benchmarking B cell epitope prediction: Underperformance of existing methods

“…Though anecdotal evidence suggests that profiles can accurately predict linear epitopes in some instances (Castelletti et al 2004; Hua et al 2004), our results support the null hypothesis: Amino acid propensity profiles cannot be used effectively to predict linear epitopes. It is possible, although unlikely, that as‐yet‐undiscovered scales may perform adequately.…”

“…Although most epitopes are thought to be discontinuous (Barlow et al 1986), experimental epitope detection has focused on linear epitopes. The accurate in silico prediction of linear epitopes from protein sequences is highly desirable and is thought to be achievable by using amino acid scales to create sequence profiles (Castelletti et al 2004; Hua et al 2004). Though the predictive accuracy of such methods has been examined previously (Hopp 1986; Van Regenmortel and Daney de Marcillac 1988; Pellequer et al 1994), the extensive and objective analysis we present here is the most comprehensive to date.…”

SARS-CoV Genome Polymorphism: A Bioinformatics Study

“…Several epitope sites, defined by polyclonal or monoclonal antibodies, have been identified on the S protein, depending on experimental conditions, all lying within wide or narrow regions between a.a. 12-1,192 20., 21., 22., 23., 24., 25., 26., 27., 28., 29., 30., 31.. Defining conserved immunodominant epitope regions of the S protein is of crucial importance for future anti-SARS vaccine development.…”

Identification and Antigenic Epitope Mapping of Immunodominant Region Amino Residues 510 to 672 on the Spike Protein of the Severe Acute Respiratory Syndrome Coronavirus

“…Linear neutralization epitopes have been identified in other coronaviruses (Daniel et al, 1993). Recently, some linear epitopes were identified in the SARS-CoV spike protein (Choy et al, 2004;Hua et al, 2004;Zhang et al, 2004;Zhou et al, 2004). In this study, with a prokaryotic expression system, we identified four linear antigenic epitopes.…”