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Exploring the Immunodominant Epitopes of SARS-CoV-2 Nucleocapsid Protein as Exposure Biomarker
Background The nucleocapsid protein (N protein) of SARS-CoV-2 is undeniably a potent target for the development of diagnostic tools due to its abundant expression and lower immune evasion pressure compared to spike (S) protein. Methods Blood samples of active COVID-19 infections (n=71) and post-COVI...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Cureus
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10008226/ https://www.ncbi.nlm.nih.gov/pubmed/36919074 http://dx.doi.org/10.7759/cureus.34827 |
Sumario: | Background The nucleocapsid protein (N protein) of SARS-CoV-2 is undeniably a potent target for the development of diagnostic tools due to its abundant expression and lower immune evasion pressure compared to spike (S) protein. Methods Blood samples of active COVID-19 infections (n=71) and post-COVID-19 (n=11) were collected from a tertiary care hospital in India; pre-COVID-19 (n=12) sera samples served as controls. Real-time reverse transcriptase-PCR (rRT-PCR) confirmed pooled sera samples (n=5) were used with PEPperCHIP® SARS-CoV-2 Proteome Microarray (PEPperPRINT GmbH, Germany) to screen immunodominant epitopes of SARS-CoV-2. Highly immunodominant epitopes were then commercially synthesized and further validated for their immunoreactivity by dot-blot and ELISA. Results The lowest detectable concentration (LDC) of the N1 peptide in the dot-blot assay was 12.5 µg demonstrating it to be fairly immunoreactive compared to control sera. IgG titers against the contiguous peptide (N2: 156AIVLQLPQGTTLPKGFYAEGS176) was found to be significantly higher (p=0.018) in post-COVID-19 compared to pre-COVID-19 control sera. These results suggested that N2-specific IgG titers buildup over time as expected in post-COVID-19 sera samples, while a non-significant immunoreactivity of the N2 peptide was also observed in active-COVID-19 sera samples. However, there were no significant differences in the total IgG titers between active COVID-19 infections, post-COVID-19 and pre-COVID-19 controls. Conclusion The N2-specific IgG titers in post-COVID-19 samples demonstrated the potential of N protein as an exposure biomarker, particularly in sero-surveillance studies. |
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