Abstract
Serological testing is important method for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Nucleocapsid (N) protein is the most abundant virus derived protein and strong immunogen. We aimed to find its efficient, low-cost production. SARS-CoV-2 recombinant fragment of nucleocapsid protein (rfNP; 58-419 aa) was expressed in E. coli in soluble form, purified and characterized biochemically and immunologically. Purified rfNP has secondary structure of full-length recombinant N protein, with high percentage of disordered structure (34.2%) and of β-sheet (40.7%). rfNP was tested in immunoblot using sera of COVID-19 convalescent patients. ELISA was optimized with sera of RT-PCR confirmed positive symptomatic patients and healthy individuals. IgG detection sensitivity was 96% (47/50) and specificity 97% (67/68), while IgM detection was slightly lower (94% and 96.5%, respectively). Cost-effective approach for soluble recombinant N protein fragment production was developed, with reliable IgG and IgM antibodies detection of SARS-CoV-2 infection.
Keywords: COVID-19; Prokaryotic expression; Recombinant nucleocapsid protein; SARS-CoV-2; serological assay.
【저자키워드】 COVID-19, SARS-CoV-2, Recombinant nucleocapsid protein, Serological assay, Prokaryotic expression, 【초록키워드】 IgG, IgM, coronavirus, antibody, SARS-COV-2 infection, Infection, Diagnosis, severe acute respiratory syndrome Coronavirus, RT-PCR, virus, ELISA, nucleocapsid protein, Protein, specificity, Recombinant nucleocapsid protein, Serological assay, Serological testing, IgM antibodies, nucleocapsid, sera, N protein, respiratory, Detection sensitivity, recombinant, secondary structure, IgG and IgM, fragment of, acute respiratory syndrome, E. coli, derived protein, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, healthy individuals, positive, full-length, immunoblot, approach, COVID-19 convalescent patients, β-sheet, characterized, expressed, biochemically, purified, immunologically, symptomatic patient, was tested, 【제목키워드】 purification, immunological,