Identification of immunodominant epitopes on nucleocapsid and spike proteins of the SARS-CoV-2 in Iranian COVID-19 patients

Maghsood, Faezeh; Shokri, Fazel; Jeddi‐Tehrani, Mahmood; Rahvar, Monireh Torabi; Ghaderi, Abbas; Salimi, Vahid; Kardar, Gholam Ali; Zarnani, Amir‐Hassan; Amiri, Mohammad Mehdi

doi:10.1093/femspd/ftac001

Cited by 9 publications

(14 citation statements)

References 34 publications

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“…Our results showed that the antibody response in BALB/c mice is largely directed against linear epitopes. These findings are different from our previous results obtained from COVID-19 convalescent sera which showed that the antibody response is mainly directed against conformational epitopes of RBD in human ( 42 ).…”

Section: Discussioncontrasting

confidence: 99%

Epitope mapping of severe acute respiratory syndrome coronavirus 2 neutralizing receptor binding domain-specific monoclonal antibodies

et al. 2022

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the outbreak led to the coronavirus disease 2019 (COVID-19) pandemic. Receptor binding domain (RBD) of spike (S) protein of SARS-CoV-2 is considered as a major target for immunotherapy and vaccine design. Here, we generated and characterized a panel of anti-RBD monoclonal antibodies (MAbs) isolated from eukaryotic recombinant RBD-immunized mice by hybridoma technology. Epitope mapping was performed using a panel of 20-mer overlapping peptides spanning the entire sequence of the RBD protein from wild-type (WT) Wuhan strain by enzyme-linked immunosorbent assay (ELISA). Several hybridomas showed reactivity toward restricted RBD peptide pools by Pepscan analysis, with more focus on peptides encompassing aa 76–110 and 136–155. However, our MAbs with potent neutralizing activity which block SARS-CoV-2 spike pseudovirus as well as the WT virus entry into angiotensin-converting enzyme-2 (ACE2) expressing HEK293T cells showed no reactivity against these peptides. These findings, largely supported by the Western blotting results suggest that the neutralizing MAbs recognize mainly conformational epitopes. Moreover, our neutralizing MAbs recognized the variants of concern (VOC) currently in circulation, including alpha, beta, gamma, and delta by ELISA, and neutralized alpha and omicron variants at different levels by conventional virus neutralization test (CVNT). While the neutralization of MAbs to the alpha variant showed no substantial difference as compared with the WT virus, their neutralizing activity was lower on omicron variant, suggesting the refractory effect of mutations in emerging variants against this group of neutralizing MAbs. Also, the binding reactivity of our MAbs to delta variant showed a modest decline by ELISA, implying that our MAbs are insensitive to the substitutions in the RBD of delta variant. Our data provide important information for understanding the immunogenicity of RBD, and the potential application of the novel neutralizing MAbs for passive immunotherapy of SARS-CoV-2 infection.

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Section: Discussioncontrasting

confidence: 99%

Epitope mapping of severe acute respiratory syndrome coronavirus 2 neutralizing receptor binding domain-specific monoclonal antibodies

et al. 2022

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“…It may be due to the higher viral load during early infection in the severe patients that leads to higher antibody levels 116 . In consistence with this finding, we displayed strong reactivity of COVID‐19 patient's sera with a single peptide spanning aa 151–170 located on RNA‐binding terminal domain of N protein, and confirmed this finding by peptide depletion experiments using both ELISA and Western blotting 117 . In contrast, immunisation of Balb/C mice with recombinant N protein showed immunodominance of a peptide spanning aa 391–419 (unpublished data).…”

Section: Epitope Mapping Of B Cell Responses Against N Proteinsupporting

confidence: 75%

“…116 In consistence with this finding, we displayed strong reactivity of COVID-19 patient's sera with a single peptide spanning aa 151-170 located on RNA-binding terminal domain of N protein, and confirmed this finding by peptide depletion experiments using both ELISA and Western blotting. 117 In contrast, immunisation of Balb/C mice with recombinant N protein showed immunodominance of a peptide spanning aa 391-419 (unpublished data). Profiling of another panel of anti-N MAbs (4G3, 5B3, 12B6, 18C7-A2, 21H10-A3, 21H10-E9) by peptide-ELISA and dot-blot assay demonstrated that aa 401-408 constitutes the main linear epitope which is highly conserved among VOIs and VOCs.…”

Section: Epitope Mapping Of B Cell Responses Against N Proteinmentioning

confidence: 98%

SARS‐CoV‐2 nucleocapsid: Biological functions and implication for disease diagnosis and vaccine design

Maghsood

Ghorbani

Yadegari

et al. 2023

Reviews in Medical Virology

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The coronavirus disease 2019 (COVID‐19) pandemic is transmitted by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and has affected millions of people all around the world, leading to more than 6.5 million deaths. The nucleocapsid (N) phosphoprotein plays important roles in modulating viral replication and transcription, virus‐infected cell cycle progression, apoptosis, and regulation of host innate immunity. As an immunodominant protein, N protein induces strong humoral and cellular immune responses in COVID‐19 patients, making it a key marker for studying N‐specific B cell and T cell responses and the development of diagnostic serological assays and efficient vaccines. In this review, we focus on the structural and functional features and the kinetic and epitope mapping of B cell and T cell responses against SARS‐CoV‐2 N protein to extend our understanding on the development of sensitive and specific diagnostic immunological tests and effective vaccines.

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“…In a recent study, we performed epitope mapping of RBD in COVID‐19 patients' sera using a panel of linear epitopes spanning RBD. Our results demonstrated involvement of mostly conformational disulfide bond‐dependent epitopes in RBD‐specific IgG antibody 43 . Review of literature for neutralising anti‐SARS‐CoV‐2 MAbs indicates that all reported nAbs recognise epitopes within only the S protein and most of them are directed against the RBD (Figure 3, Table 1).…”

Section: Epitope Mapping Of Neutralising Anti‐sars‐cov‐2 Mabsmentioning

confidence: 57%

“…Identification of the target epitope of an antibody molecule is instrumental in development of effective prophylactic therapeutics and epitope-based vaccines as well as molecular elucidation of MAb neutralising activities. 41,42 In a recent study, we performed epitope mapping of RBD in COVID-19 patients' sera using a panel of linear 43 . Review of literature for neutralising anti-SARS-CoV-2 MAbs indicates that all reported nAbs recognise epitopes within only the S protein and most of them are directed against the RBD (Figure 3, Table 1).…”

Section: Epitope Mapping Of Neutralising Anti-sars-cov-2 Mabsmentioning

confidence: 99%

Epitope mapping of neutralising anti‐SARS‐CoV‐2 monoclonal antibodies: Implications for immunotherapy and vaccine design

Ghotloo

Maghsood

Golsaz‐Shirazi

et al. 2022

Reviews in Medical Virology

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Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is the causative agent of the coronavirus disease 2019 (COVID‐19) pandemic. This disease has currently affected more than 346 million people and resulted in more than 5.5 million deaths in many countries. Neutralising monoclonal antibodies (MAbs) against the SARS‐CoV‐2 virus could serve as prophylactic/therapeutic agents in COVID‐19 infection by providing passive protection against the virus in individuals. Until now, no Food and Drug Administration/European Medicines Agency‐approved neutralising MAb against SARS‐CoV‐2 virus exists in the market, though a number of MAbs have been authorised for emergency use. Therefore, there is an urgent need for development of efficient anti‐SARS‐CoV‐2 neutralising MAbs for use in the clinic. Moreover, neutralising anti‐SARS‐CoV‐2 MAbs could be used as beneficial tools for designing epitope‐based vaccines against the virus. Given that the target epitope of a MAb is a crucial feature influencing its neutralising potency, target epitopes of neutralising anti‐SARS‐CoV‐2 MAbs already reported in the literature and reactivity of these MAbs with SARS‐CoV‐2 variants are reviewed herein.

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Identification of immunodominant epitopes on nucleocapsid and spike proteins of the SARS-CoV-2 in Iranian COVID-19 patients

Cited by 9 publications

References 34 publications

Epitope mapping of severe acute respiratory syndrome coronavirus 2 neutralizing receptor binding domain-specific monoclonal antibodies

Epitope mapping of severe acute respiratory syndrome coronavirus 2 neutralizing receptor binding domain-specific monoclonal antibodies

SARS‐CoV‐2 nucleocapsid: Biological functions and implication for disease diagnosis and vaccine design

Epitope mapping of neutralising anti‐SARS‐CoV‐2 monoclonal antibodies: Implications for immunotherapy and vaccine design

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