Towards Quantitative and Standardized Serological and Neutralization Assays for COVID-19 |
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| Authors: | Linhua Tian Elzafir B Elsheikh Paul N Patrone Anthony J Kearsley Adolfas K Gaigalas Sarah Inwood Sheng Lin-Gibson Dominic Esposito Lili Wang |
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| Affiliation: | 1.Biosystems and Biomaterials Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA; (L.T.); (E.B.E.); (A.K.G.); (S.I.); (S.L.-G.);2.Applied and Computational Mathematics Division, NIST, Gaithersburg, MD 20899, USA; (P.N.P.); (A.J.K.);3.Frederick National Laboratory for Cancer Research (FNLCR), Frederick, MD 21702, USA; |
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| Abstract: | Quantitative and robust serology assays are critical measurements underpinning global COVID-19 response to diagnostic, surveillance, and vaccine development. Here, we report a proof-of-concept approach for the development of quantitative, multiplexed flow cytometry-based serological and neutralization assays. The serology assays test the IgG and IgM against both the full-length spike antigens and the receptor binding domain (RBD) of the spike antigen. Benchmarking against an RBD-specific SARS-CoV IgG reference standard, the anti-SARS-CoV-2 RBD antibody titer was quantified in the range of 37.6 µg/mL to 31.0 ng/mL. The quantitative assays are highly specific with no correlative cross-reactivity with the spike proteins of MERS, SARS1, OC43 and HKU1 viruses. We further demonstrated good correlation between anti-RBD antibody titers and neutralizing antibody titers. The suite of serology and neutralization assays help to improve measurement confidence and are complementary and foundational for clinical and epidemiologic studies. |
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| Keywords: | SARS-CoV-2 virus quantitative serology assays IgG IgM spike RBD monoclonal antibody reference standard neutralization assay cross reactivity sensitivity and specificity |
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