Screening and Identification of Linear B-Cell Epitopes and Entry-Blocking Peptide of Severe Acute Respiratory Syndrome (SARS)-Associated Coronavirus Using Synthetic Overlapping Peptide Library

Abstract

A 10-mer overlapping peptide library has been synthesized for screening and identification of linear B-cell epitopes of severe acute respiratory syndrome associated coronavirus (SARS-CoV), which spanned the major structural proteins of SARS-CoV. One hundred and eleven candidate peptides were positive according to the result of PEPscan, which were assembled into 22 longer peptides. Five of these peptides showed high cross-immunoreactivities (approximately 66.7 to 90.5%) to SARS convalescent patients' sera from the severest epidemic regions of the China mainland. Most interestingly, S(471-503), a peptide located at the receptor binding domain (RBD) of SARS-CoV, could specifically block the binding between the RBD and angiotensin-converting enzyme 2, resulting in the inhibition of SARS-CoV entrance into host cells in vitro. The study demonstrated that S(471-503) peptide was a potential immunoantigen for the development of peptide-based vaccine or a candidate for further drug evaluation against the SARS-CoV virus-cell fusion.

Priming with SARS CoV S DNA and boosting with SARS CoV S epitopes specific for CD4+ and CD8+ T cells promote cellular immune responses

“…It has been reported that SARS CoV S DNA vaccine could induce neutralizing antibodies, which played important roles in protective immune responses to virus infection. Furthermore, several B cell epitopes, such as S471-503, S803-828, S1061-1093, S335-352 and S442-458, in SARS CoV S protein were identified [39][40][41]. However, T cell epitopes N50 and N60 could not generate antibodies in our study, indicating that N50 and N60 could not be B cell epitopes.…”

Identification of a B-cell antigenic epitope at the N-terminus of SARS-CoV M protein and characterization of monoclonal antibody against the protein

“…They demonstrated that five of assembled 22 longer peptides showed high crossimmunoreactivities to 42 SARS convalescent patients' sera from the severest epidemic regions of the China mainland. Among them, S471-503, a peptide located at the receptor binding domain (RBD) of SARS-CoV, could specifically block the binding between the RBD and angiotensin-converting enzyme 2, resulting in the inhibition of SARS-CoV entrance into host cells in vitro [35]. In current study, we demonstrated a linear B-cell antigenic epitope located in the M protein between 1 and 15 aa, which was consistent with the previous reports [7,8].…”

“…Lane 1: total cellular extracts from IPTGinduced BL21 transformed with recombinant pSARS-M construct (control); Lane 2: total cellular extracts from IPTGinduced BL21 transformed with recombinant pSARS-Ml construct; Lane 3: total cellular extracts from IPTG-induced BL21 transformed with recombinant pSARS-M2 construct antigenic epitope(s) may still locate in this region. While Hu et al has identified the B-cell antigenic epitope on S2 protein, they also found that two synthesized overlapping peptides, both of which were located within amino acids 29-48 of M protein, could react to mixture of 42 SARS convalescent patients' sera, indicating that other potential B-cell antigenic epitope(s) may still locate in this region [35]. Meanwhile, our experiment showed that the recognizing region of the MAb against M fragment was in the M protein between amino acids 16 and 28.…”

Learning from the Past: Possible Urgent Prevention and Treatment Options for Severe Acute Respiratory Infections Caused by 2019‐nCoV

“…[8,13,14] Similar ideas could be applied in de-veloping2 019-nCoV vaccines. [22] Onep eptide comprising two ACE2 motifs (aa 22-44a nd 351-357) linked by glycine exhibited potent anti-SARS activity with an IC 50 value of 0.1 mm. [15] Although there are published resultsa bout therapeutic antibodiesa nd peptides developed to neutralize the SARS-CoV spike protein, they are expectedt oh ave little use in neutralizing 2019-nCoV.A sd iscussed above, the two engaging regions in the spike RBD for bindingA CE2 are very different between SARS-CoV and 2019-nCoV.A ntibodies and peptides targeting two regions in the SARS-CoV RBD are expected to interact weaklyw itht he 2019-nCoV RBD.…”