Immunological Characterization of the Spike Protein of the Severe Acute Respiratory Syndrome Coronavirus

Abstract

Severe acute respiratory syndrome (SARS) is a novel infectious disease caused by the SARS-associated coronavirus (SARS-CoV). There are four major structural proteins in the SARS-CoV, including the nucleocapsid, spike, membrane, and small envelope proteins. In this study, two sets of truncated fragments of spike protein were generated, the first were approximately 210-bp nonoverlapping fragments and the second were overlapping segments of 750 to 900 bp. From these 23 fragments, we identified a fragment of 259 amino acids (amino acids 441 to 700) that is a major immunodominant epitope. This fragment was highly expressed, and the purified fragment C could detect all 33 SARS patient serum samples tested, collected from 7 to 60 days after the onset of fever, but had no reactivity with all 66 healthy human serum samples tested. Thus, fragment C of spike protein was identified as an immunodominant antigen and could be used for serological detection of SARS-CoV infection.

Identification of Immunodominant Sites on the Spike Protein of Severe Acute Respiratory Syndrome (SARS) Coronavirus: Implication for Developing SARS Diagnostics and Vaccines

“…This is consistent with the reports by Lu et al (28) and Wang et al (29), in which they demonstrated that the fragments of aa 441-700 and 599 -620, which overlap with sequence of site IV, also reacted with most SARS sera tested. We further showed that several peptides derived from site IV were strongly reactive with the antisera from mice and rabbits immunized with inactivated SARS-CoV (Figs.…”

Newcastle disease virus, a host range-restricted virus, as a vaccine vector for intranasal immunization against emerging pathogens

“…Because insertion of foreign genes into genomes of nonsegmented negative strand viruses such as NDV can confer attenuation that increases with insert size (34), we also made a separate NDV-BC-vectored vaccine construct expressing the N-terminal 762-aa S1 domain (NDV-BC/S1). The S1 domain has been reported to contain the receptor-binding site of S as well as major neutralizing epitopes (35). The various vaccine viruses were readily recovered and amplified, achieving peak titers of Ϸ10 7.5 to 10 8.0 pfu/ml in DF-1 cells and 10 8.5 to 10 9.0 in embryonated chicken eggs (data not shown).…”

The Immunobiology of SARS

“…Among the structural proteins, including M, E, and N, only the S protein elicits neutralizing antibody (138). The major immunodominant epitope in S protein lies between amino acids 441 and 700 (139).…”