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

Abstract

The severe acute respiratory syndrome (SARS) is a newly emerging human infectious disease caused by the severe acute respiratory syndrome coronavirus (SARS-CoV). The spike (S) protein of SARS-CoV is a major virion structural protein. It plays an important role in the interaction with receptors and neutralizing antibodies. In this study, the S1 domain of the spike protein and three truncated fragments were expressed by fusion with GST in a pGEX-6p-1 vector. Western blot results demonstrated that the 510-672 fragment of the S1 domain is a linear epitope dominant region. To map the antigenic epitope of this linear epitope dominant region, a set of 16 partially overlapping fragments spanning the fragment were fused with GST and expressed. Four antigenic epitopes S1C3 (539-559), S1C4 (548-567), S1C7/8 (583-606), and S1C10/11 (607-630) were identified. Immunization of mice with each of the four antigenic epitope-fused proteins revealed that all four proteins could elicit spike protein specific antisera. All of them were able to bind to the surface domain of the whole spike protein expressed by recombinant baculovirus in insect cells. Identification of antigenic epitopes of the spike protein of SARS-CoV may provide the basis for the development of immunity-based prophylactic, therapeutic, and diagnostic clinical techniques for the severe acute respiratory syndrome.

A dominant antigenic epitope on SARS-CoV spike protein identified by an avian single-chain variable fragment (scFv)-expressing phage

“…Because the SARS-CoV S protein can induce neutralizing antibodies, it is a suitable candidate for developing vaccine and diagnostic applications. Our mapping results showed that fragments Se-e (aa 456-650), Sf-f (aa 600-800) and Sg-g (aa 750-1000), reacting with 70, 70 and 100% of patients' sera, respectively (Table 1), covered most potential epitopic regions reported elsewhere Greenough et al, 2005;He et al, 2004;Hua et al, 2005;Ren et al, 2003;Wang et al, 2005;Zhi et al, 2005). We also identified, for the first time, an additional, highly antigenic fragment Sb-b (aa 150-400), which was recognized by 70% of patients' sera.…”

A chimeric multi-epitope DNA vaccine elicited specific antibody response against severe acute respiratory syndrome-associated coronavirus which attenuated the virulence of SARS-CoV in vitro

“…Hence, identification of neutralization epitopes within S and M sequence may enable the design of epitope-based SARS vaccines [9]. A couple of immunodominant epitopes from S and M protein of SARS-CoV have been identified through online epitope predication software or epitope mapping technologies and used for potential vaccine targets and therapeutic reagents [10][11][12].…”

A study on antigenicity and receptor-binding ability of fragment 450–650 of the spike protein of SARS coronavirus

“…As the receptor binding site of SARS-CoV, S-RBD is the most likely target for neutralizing Abs against the virus. Several groups have mapped a number of B cell epitopes in, or around, the S-RBD region (Hu et al, 2005;Hua et al, 2004Hua et al, , 2005Lu et al, 2005;Wang et al, 2003), although the exact location and conformational structure of such epitopes remain to be clarified. Our previous results demonstrated that SARS patients mounted early and strong humoral responses against fragment 450-650 of the S protein (S450-650) (Zhao et al, 2005a(Zhao et al, , 2005b, which contains the β6, but not β5, strand of the S-RBM.…”