Nucleoprotein-based ELISA for detection of SARS-COV-2 IgG antibodies: Could an old assay be suitable for serodiagnosis of the new coronavirus?

Tania Regina Tozetto-Mendoza; Kelly Aparecida Kanunfre; Lucy Santos Vilas-Boas; Evelyn Patricia Sanchez Espinoza; Heuder Gustavo Oliveira Paião; Mussya Cisotto Rocha; Anderson Vicente de Paula; Maura Salaroli de Oliveira; Daniella Bosco Zampelli; José Mauro Vieira Jr; Lewis Buss; Silvia Figueiredo Costa; Ester Cerdeira Sabino; Steven S Witkin; Thelma Suely Okay; Maria Cassia Mendes-Correa

doi:10.1016/j.jviromet.2021.114064

Nucleoprotein-based ELISA for detection of SARS-COV-2 IgG antibodies: Could an old assay be suitable for serodiagnosis of the new coronavirus?

J Virol Methods. 2021 Apr:290:114064. doi: 10.1016/j.jviromet.2021.114064. Epub 2021 Jan 13.

Authors

Tania Regina Tozetto-Mendoza¹, Kelly Aparecida Kanunfre², Lucy Santos Vilas-Boas³, Evelyn Patricia Sanchez Espinoza⁴, Heuder Gustavo Oliveira Paião⁵, Mussya Cisotto Rocha², Anderson Vicente de Paula³, Maura Salaroli de Oliveira⁶, Daniella Bosco Zampelli⁷, José Mauro Vieira Jr⁷, Lewis Buss⁸, Silvia Figueiredo Costa⁴, Ester Cerdeira Sabino⁹, Steven S Witkin¹⁰, Thelma Suely Okay¹¹, Maria Cassia Mendes-Correa⁵

Affiliations

¹ LIM-52, Institute of Tropical Medicine, School of Medicine, Clinical Hospital, University of São Paulo, Brazil. Electronic address: [email protected].
² LIM-48, Clinical Hospital, School of Medicine, University of São Paulo, Brazil; Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, School of Medicine, University of São Paulo, Brazil.
³ LIM-52, Institute of Tropical Medicine, School of Medicine, Clinical Hospital, University of São Paulo, Brazil.
⁴ LIM-49, Institute of Tropical Medicine, School of Medicine, University of São Paulo, Brazil; Department of Infection Diseases, Clinical Hospital, School of Medicine, University of São Paulo, Brazil.
⁵ LIM-52, Institute of Tropical Medicine, School of Medicine, Clinical Hospital, University of São Paulo, Brazil; Department of Infection Diseases, Clinical Hospital, School of Medicine, University of São Paulo, Brazil.
⁶ Department of Infection control- Clinical Hospital, School of Medicine, University of São Paulo, Brazil; Hospital Sírio Libanês, Brazil.
⁷ Hospital Sírio Libanês, Brazil.
⁸ Department of Infection Diseases, Clinical Hospital, School of Medicine, University of São Paulo, Brazil.
⁹ Department of Infection Diseases, Clinical Hospital, School of Medicine, University of São Paulo, Brazil; LIM-46, Institute of Tropical Medicine, School of Medicine, University of São Paulo, Brazil.
¹⁰ LIM-52, Institute of Tropical Medicine, School of Medicine, Clinical Hospital, University of São Paulo, Brazil; Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, New York, United States.
¹¹ Laboratory of Seroepidemiology and Immunobiology, Institute of Tropical Medicine, School of Medicine, University of São Paulo, Brazil; Department of Pediatrics, School of Medicine, University of São Paulo, Brazil.

Abstract

Objectives: We evaluated the performance of a nucleoprotein-based enzyme-linked immunosorbent assay (ELISA) for detection of IgG antibodies to SARS-CoV-2.

Methods: The ELISA was based on serum IgG reactivity to a 46-kDa protein derived from the recombinant SARS-CoV2 nucleoprotein. Assay sensitivity was assessed using serum samples from 134 COVID-19 confirmed cases obtained > 15 days after symptom onset. Specificity was determined by testing sera from 94 healthy controls. Cross-reactivity was evaluated with sera from 96 individuals with previous dengue or zika virus-confirmed infections, with 44 sera from individuals with confirmed infections to other respiratory viruses or with bacterial and fungal infections that cause pneumonia and with 40 sera negative for SARS-CoV-2 nucleoprotein by commercial ELISA kits.

Results: The majority of subjects were male and ≥ 60 years old. Assay sensitivity was 90.3 % (95 % confidence interval 84.1 %-94.2 %) and specificity was 97.9 % (92.6 %-99.4 %). There was no cross-reactivity with sera from individuals diagnosed with dengue, zika virus, influenza virus, rhinovirus, adenovirus, respiratory syncytial virus, seasonal coronavirus, Mycobacterium tuberculosis, Staphylococcus (S. aureus and coagulase-negative), Streptococcus pneumoniae, Klebsiella pneumoniae and the fungus Aspergillus fumigatus. The level of concordance of our test with results from commercial ELISA kits was 100 %.

Conclusion: The nucleoprotein-based ELISA was specific for detection of IgG anti-nucleoprotein antibodies to SARS-CoV-2. It utilizes a frequently employed low expense assay protocol and is easier to perform than other currently available commercial SARS-CoV2 antibody detection tests.

Keywords: COVID-19; ELISA; IgG antibody; Nucleoprotein antigen; SARS-CoV-2.

Publication types

Evaluation Study
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Antibodies, Viral / blood
Antibodies, Viral / immunology
COVID-19 / diagnosis*
COVID-19 Serological Testing*
Coronavirus Nucleocapsid Proteins / immunology*
Enzyme-Linked Immunosorbent Assay*
Female
Humans
Immunoglobulin G / blood*
Immunoglobulin G / immunology
Male
Middle Aged
Phosphoproteins / immunology
SARS-CoV-2 / immunology
SARS-CoV-2 / isolation & purification*
Sensitivity and Specificity

Substances

Antibodies, Viral
Coronavirus Nucleocapsid Proteins
Immunoglobulin G
Phosphoproteins
nucleocapsid phosphoprotein, SARS-CoV-2