Rapid and quantitative detection of SARS-CoV-2 specific IgG for convalescent serum evaluation

• Published in: Biosensors & bioelectronics 2020-12, Vol.169, p.112572-112572, Article 112572
• Main Authors: Tan, Xiaotian, Krel, Mila, Dolgov, Enriko, Park, Steven, Li, Xuzhou, Wu, Weishu, Sun, Yun-Lu, Zhang, Jie, Khaing Oo, Maung Kyaw, Perlin, David S., Fan, Xudong
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Antibodies, Viral - blood; Antibodies, Viral - immunology; Antibody detection; Antigens, Viral - blood; Antigens, Viral - immunology; Betacoronavirus - immunology; Biosensing Techniques - economics; Biosensing Techniques - instrumentation; Coronavirus Infections - therapy; Coronavirus Infections - virology; COVID-19; COVID-19 Serotherapy; Enzyme-Linked Immunosorbent Assay - economics; Enzyme-Linked Immunosorbent Assay - instrumentation; Equipment Design; Humans; Immunization, Passive; Immunoassay; Immunoglobulin G - blood; Immunoglobulin G - immunology; Limit of Detection; Luminescent Measurements - economics; Luminescent Measurements - instrumentation; Microfluidic Analytical Techniques - economics; Microfluidic Analytical Techniques - instrumentation; Microfluidics; Middle Aged; Pandemics; Pneumonia, Viral - therapy; Pneumonia, Viral - virology; SARS-CoV-2; Time Factors; Young Adult
• ISSN: 0956-5663; 1873-4235; 1873-4235
• DOI: 10.1016/j.bios.2020.112572

Convalescent serum with a high abundance of neutralization IgG is a promising therapeutic agent for rescuing COVID-19 patients in the critical stage. Knowing the concentration of SARS-CoV-2 S1-specific IgG is crucial in selecting appropriate convalescent serum donors. Here, we present a portable microfluidic ELISA technology for rapid (15 min), quantitative, and sensitive detection of anti-SARS-CoV-2 S1 IgG in human serum with only 8 μL sample volume. We first identified a humanized monoclonal IgG that has a high binding affinity and a relatively high specificity towards SARS-CoV-2 S1 protein, which can subsequently serve as the calibration standard of anti-SARS-CoV-2 S1 IgG in serological analyses. We then measured the abundance of anti-SARS-CoV-2 S1 IgG in 16 convalescent COVID-19 patients. Due to the availability of the calibration standard and the large dynamic range of our assay, we were able to identify “qualified donors” for convalescent serum therapy with only one fixed dilution factor (200 ×). Finally, we demonstrated that our technology can sensitively detect SARS-CoV-2 antigens (S1 and N proteins) with pg/mL level sensitivities in 40 min. Overall, our technology can greatly facilitate rapid, sensitive, and quantitative analysis of COVID-19 related markers for therapeutic, diagnostic, epidemiologic, and prognostic purposes. •Identified a calibrator antibody for anti-SARS-CoV-2 S1 IgG quantification.•Rapid (15 min) and sensitive detection of anti-SARS-CoV-2S1 IgG in serum.•Quantitative evaluation of COVID-19 convalescent serum with a single dilution factor (200X).•Sensitive detection of SARS-CoV-2 N- and S-protein in serum down to ~10 pg/mL with 3-4 orders of magnitude dynamic range.•8 μL sample/reagent volume.