Quantification of antibody avidities and accurate detection of SARS-CoV-2 antibodies in serum and saliva on plasmonic substrates
Tiancheng Liu, Jessica Hsiung, Su Zhao, Jessica Kost, Deepika Sreedhar, Carl V. Hanson, Kjerstie Olson, Douglas Keare, Shin Ting Chang, Kevin P. Bliden, Paul A. Gurbel, Udaya S. Tantry, John Roche, Cynthia Press, John Boggs, Jorge P. Rodriguez-Soto, Jose G. Montoya, Meijie Tang & Hongjie Dai
Nature Biomedical Engineering (2020)
Abstract
Accurate assays for the detection of antibodies to SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) are essential for the control of the COVID-19 (coronavirus disease 2019) pandemic. Here, we report antibody and antibody-avidity assays, relying on near-infrared-fluorescence amplification by nanostructured plasmonic gold substrates, for the simultaneous detection of antibodies to the S1 subunit of the spike protein and to the receptor binding domain of SARS-CoV-2 in human serum and saliva, and for quantifying immunoglobulin avidities against coronavirus antigens from SARS-CoV-2, SARS-CoV-1 and the common-cold viruses OC43, HKU1, NL63 and 229E. The antibody assay detected immunoglobulin M in 87% (52 of 60) COVID-19-positive serum samples collected 6 or more days after symptom onset (and the immunoglobulins M and G in all 33 samples collected at least 15 days after symptom onset), and correctly classified 456 out of the 457 COVID-19-negative serum samples tested (424 of them collected before the pandemic, including 73 that were positive for other viruses). We used the antibody-avidity assay to study antibody-maturation patterns, anamnestic responses, and cross-immunity to the common-cold coronaviruses.
