In Vitro Diagnostic Assay to Detect SARS-CoV-2-Neutralizing Antibody in Patient Sera Using Engineered ACE-2 Mini-Protein
Bruna Andersen Pereira de Jesus,
Anderson Albino Gomes,
Alex E. Clark,
Tayse Andrade Rodrigues,
Melissa Ledgerwood-Lee,
Westley Van Zant,
Howard Brickner,
Meiqiao Wang,
David L. Blum,
Maria B. Cassera,
Aaron F. Carlin,
Eliah S. Aronoff-Spencer,
Gustavo Felippe da Silva,
Maria de Lourdes Borba Magalhães,
Partha Ray
Affiliations
Bruna Andersen Pereira de Jesus
Biochemistry Laboratory, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages 88520-000, Brazil
Anderson Albino Gomes
Biochemistry Laboratory, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages 88520-000, Brazil
Alex E. Clark
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
Tayse Andrade Rodrigues
Research and Development Department, Bioclin<sup>®</sup>, Belo Horizonte 31565-130, Brazil
Melissa Ledgerwood-Lee
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
Westley Van Zant
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
Howard Brickner
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
Meiqiao Wang
Bioexpression and Fermentation Facility, University of Georgia, Athens, GA 30602, USA
David L. Blum
Bioexpression and Fermentation Facility, University of Georgia, Athens, GA 30602, USA
Maria B. Cassera
Department of Biochemistry and Molecular Biology and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, GA 30602, USA
Aaron F. Carlin
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
Eliah S. Aronoff-Spencer
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
Gustavo Felippe da Silva
Biochemistry Laboratory, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages 88520-000, Brazil
Maria de Lourdes Borba Magalhães
Biochemistry Laboratory, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages 88520-000, Brazil
Partha Ray
Department of Medicine, Division of Infectious Diseases and Global Public Health, University of California, San Diego, CA 92093, USA
The recent development and mass administration of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccines allowed for disease control, reducing hospitalizations and mortality. Most of these vaccines target the SARS-CoV-2 Spike (S) protein antigens, culminating with the production of neutralizing antibodies (NAbs) that disrupt the attachment of the virus to ACE2 receptors on the host cells. However, several studies demonstrated that the NAbs typically rise within a few weeks after vaccination but quickly reduce months later. Thus, multiple booster administration is recommended, leading to vaccination hesitancy in many populations. Detecting serum anti-SARS-CoV-2 NAbs can instruct patients and healthcare providers on correct booster strategies. Several in vitro diagnostics kits are available; however, their high cost impairs the mass NAbs diagnostic testing. Recently, we engineered an ACE2 mimetic that interacts with the Receptor Binding Domain (RBD) of the SARS-2 S protein. Here we present the use of this engineered mini-protein (p-deface2 mut) to develop a detection assay to measure NAbs in patient sera using a competitive ELISA assay. Serum samples from twenty-one patients were tested. Nine samples (42.8%) tested positive, and twelve (57.1%) tested negative for neutralizing sera. The data correlated with the result from the standard commercial assay that uses human ACE2 protein. This confirmed that p-deface2 mut could replace human ACE2 in ELISA assays. Using bacterially expressed p-deface2 mut protein is cost-effective and may allow mass SARS-CoV-2 NAbs detection, especially in low-income countries where economical diagnostic testing is crucial. Such information will help providers decide when a booster is required, reducing risks of reinfection and preventing the administration before it is medically necessary.
