tetano
Editor, Senior Moderator
Virol J
. 2022 Mar 19;19(1):50.
doi: 10.1186/s12985-022-01768-4.
Sensitive and specific serological ELISA for the detection of SARS-CoV-2 infections
Ji Luo[SUP] 1 2 3 [/SUP], Alexandra Brakel[SUP] 1 2 [/SUP], Andor Krizsan[SUP] 1 2 [/SUP], Tobias Ludwig[SUP] 1 2 [/SUP], Marina Mötzing[SUP] 1 2 [/SUP], Daniela Volke[SUP] 1 2 [/SUP], Nicole Lakowa[SUP] 4 [/SUP], Thomas Grünewald[SUP] 4 [/SUP], Claudia Lehmann[SUP] 5 [/SUP], Johannes Wolf[SUP] 6 7 [/SUP], Stephan Borte[SUP] 6 7 [/SUP], Sanja Milkovska-Stamenova[SUP] 1 2 3 [/SUP], Jörg Gabert[SUP] 3 [/SUP], Felix Fingas[SUP] 3 [/SUP], Markus Scholz[SUP] 8 9 [/SUP], Ralf Hoffmann[SUP] 10 11 [/SUP]
Affiliations
Abstract
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered the worldwide coronavirus disease 2019 (COVID-19) pandemic. Serological assays for the detection of SARS-CoV-2 infections are important to understand the immune response in patients and to obtain epidemiological data about the number of infected people, especially to identify asymptomatic persons not aware of a past infection.
Methods: We recombinantly produced SARS-CoV-2 nucleocapsid (N)-protein in Escherichia coli. We used the purified protein to develop an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of SARS-CoV-2 specific antibodies. This ELISA method was optimized and validated with serum samples collected from 113 patients with RT-PCR-confirmed SARS-CoV-2 infections including hospitalized COVID-19 patients and 1500 control sera mostly collected before 2015 with different clinical background.
Results: The optimized N-protein-ELISA provided a sensitivity of 89.7% (n = 68) for samples collected from patients with confirmed SARS-CoV-2 infections and mild to severe symptoms more than 14 days after symptom onset or a positive PCR test. The antibody levels remained low for serum samples collected in the first six days (n = 23) and increased in the second week (n = 22) post symptom onset or PCR confirmation. At this early phase, the ELISA provided a sensitivity of 39.1% and 86.4%, respectively, reflecting the time of an IgG immune response against pathogens. The assay specificity was 99.3% (n = 1500; 95% CI 0.995-0.999). Serum samples from persons with confirmed antibody titers against human immunodeficiency viruses 1/2, parvovirus B19, hepatitis A/B virus, cytomegalovirus, Epstein Barr virus, and herpes simplex virus were tested negative.
Conclusions: We conclude that the N-protein-based ELISA developed here is well suited for the sensitive and specific serological detection of SARS-CoV-2 specific IgG antibodies in human serum for symptomatic infections. It may also prove useful to identify previous SARS-CoV-2 infections in vaccinated people, as all currently approved vaccines rely on the SARS-CoV-2 spike (S-) protein.
Keywords: Coronavirus disease 2019 (COVID-19); Enzyme-linked immunosorbent assay (ELISA); Nucleocapsid protein (N-protein); Serological test; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
. 2022 Mar 19;19(1):50.
doi: 10.1186/s12985-022-01768-4.
Sensitive and specific serological ELISA for the detection of SARS-CoV-2 infections
Ji Luo[SUP] 1 2 3 [/SUP], Alexandra Brakel[SUP] 1 2 [/SUP], Andor Krizsan[SUP] 1 2 [/SUP], Tobias Ludwig[SUP] 1 2 [/SUP], Marina Mötzing[SUP] 1 2 [/SUP], Daniela Volke[SUP] 1 2 [/SUP], Nicole Lakowa[SUP] 4 [/SUP], Thomas Grünewald[SUP] 4 [/SUP], Claudia Lehmann[SUP] 5 [/SUP], Johannes Wolf[SUP] 6 7 [/SUP], Stephan Borte[SUP] 6 7 [/SUP], Sanja Milkovska-Stamenova[SUP] 1 2 3 [/SUP], Jörg Gabert[SUP] 3 [/SUP], Felix Fingas[SUP] 3 [/SUP], Markus Scholz[SUP] 8 9 [/SUP], Ralf Hoffmann[SUP] 10 11 [/SUP]
Affiliations
- PMID: 35305688
- DOI: 10.1186/s12985-022-01768-4
Abstract
Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has triggered the worldwide coronavirus disease 2019 (COVID-19) pandemic. Serological assays for the detection of SARS-CoV-2 infections are important to understand the immune response in patients and to obtain epidemiological data about the number of infected people, especially to identify asymptomatic persons not aware of a past infection.
Methods: We recombinantly produced SARS-CoV-2 nucleocapsid (N)-protein in Escherichia coli. We used the purified protein to develop an indirect enzyme-linked immunosorbent assay (ELISA) for the detection of SARS-CoV-2 specific antibodies. This ELISA method was optimized and validated with serum samples collected from 113 patients with RT-PCR-confirmed SARS-CoV-2 infections including hospitalized COVID-19 patients and 1500 control sera mostly collected before 2015 with different clinical background.
Results: The optimized N-protein-ELISA provided a sensitivity of 89.7% (n = 68) for samples collected from patients with confirmed SARS-CoV-2 infections and mild to severe symptoms more than 14 days after symptom onset or a positive PCR test. The antibody levels remained low for serum samples collected in the first six days (n = 23) and increased in the second week (n = 22) post symptom onset or PCR confirmation. At this early phase, the ELISA provided a sensitivity of 39.1% and 86.4%, respectively, reflecting the time of an IgG immune response against pathogens. The assay specificity was 99.3% (n = 1500; 95% CI 0.995-0.999). Serum samples from persons with confirmed antibody titers against human immunodeficiency viruses 1/2, parvovirus B19, hepatitis A/B virus, cytomegalovirus, Epstein Barr virus, and herpes simplex virus were tested negative.
Conclusions: We conclude that the N-protein-based ELISA developed here is well suited for the sensitive and specific serological detection of SARS-CoV-2 specific IgG antibodies in human serum for symptomatic infections. It may also prove useful to identify previous SARS-CoV-2 infections in vaccinated people, as all currently approved vaccines rely on the SARS-CoV-2 spike (S-) protein.
Keywords: Coronavirus disease 2019 (COVID-19); Enzyme-linked immunosorbent assay (ELISA); Nucleocapsid protein (N-protein); Serological test; Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).