Application of a Receptor-Binding-Domain-Based Simple Immunoassay for Assessing Humoral Immunity against Emerging SARS-CoV-2 Virus Variants
Orsolya Mózner,
Judit Moldvay,
Kata Sára Szabó,
Dorottya Vaskó,
Júlia Domján,
Dorottya Ács,
Zoltán Ligeti,
Csaba Fehér,
Edit Hirsch,
László Puskás,
Cordula Stahl,
Manfred Frey,
Balázs Sarkadi
Affiliations
Orsolya Mózner
Research Centre for Natural Sciences, 1117 Budapest, Hungary
Judit Moldvay
CelluVir Biotechnology Ltd., 1094 Budapest, Hungary
Kata Sára Szabó
Research Centre for Natural Sciences, 1117 Budapest, Hungary
Dorottya Vaskó
Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1111 Budapest, Hungary
Júlia Domján
Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1111 Budapest, Hungary
Dorottya Ács
I. Department of Pulmonology, National Korányi Institute of Pulmonology, 1121 Budapest, Hungary
Zoltán Ligeti
Research Centre for Natural Sciences, 1117 Budapest, Hungary
Csaba Fehér
Biorefinery Research Group, Department of Applied Biotechnology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1111 Budapest, Hungary
Edit Hirsch
Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, 1111 Budapest, Hungary
László Puskás
Avidin Ltd., 6726 Szeged, Hungary
Cordula Stahl
Steinbeis-Innovationszentrum Zellkulturtechnik, c/o University of Applied Sciences Mannheim, Paul-Wittsack-Str. 10, D-68163 Mannheim, Germany
Manfred Frey
Steinbeis-Innovationszentrum Zellkulturtechnik, c/o University of Applied Sciences Mannheim, Paul-Wittsack-Str. 10, D-68163 Mannheim, Germany
Balázs Sarkadi
Research Centre for Natural Sciences, 1117 Budapest, Hungary
We have developed a simple, rapid, high-throughput RBD-based ELISA to assess the humoral immunity against emerging SARS-CoV-2 virus variants. The cDNAs of the His-tagged RBD proteins of the virus variants were stably engineered into HEK cells secreting the protein into the supernatant, and RBD purification was performed by Ni-chromatography and buffer exchange by membrane filtration. The simplified assay uses single dilutions of sera from finger-pricked native blood samples, purified RBD in 96-well plates, and a chromogenic dye for development. The results of this RBD-ELISA were confirmed to correlate with those of a commercial immunoassay measuring antibodies against the Wuhan strain, as well as direct virus neutralization assays assessing the cellular effects of the Wuhan and the Omicron (BA.5) variants. Here, we document the applicability of this ELISA to assess the variant-specific humoral immunity in vaccinated and convalescent patients, as well as to follow the time course of selective vaccination response. This simple and rapid assay, easily modified to detect humoral immunity against emerging SARS-CoV-2 virus variants, may help to assess the level of antiviral protection after vaccination or infection.
