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https://www.arca.fiocruz.br/handle/icict/52882
A MAGNETIC BEAD IMMUNOASSAY TO DETECT HIGH AFFINITY HUMAN IGG REACTIVE TO SARS‑COV‑2 SPIKE S1 RBD PRODUCED IN ESCHERICHIA COLI
Author
Affilliation
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Universidade Federal do Paraná. Programa de Pós-Graduação em Ciências Farmacêuticas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Hospital Erasto Gaertner. Curitiba, PR, Brasil.
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Universidade Federal do Paraná. Programa de Pós-Graduação em Ciências Farmacêuticas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Hospital Erasto Gaertner. Curitiba, PR, Brasil.
Universidade Federal do Paraná. Setor Litoral. Matinhos, PR, Brasil.
Abstract
Immunological assays to detect SARS-CoV-2 Spike Receptor Binding Domain (RBD) antigen seroconversion in humans are important tools to monitor the levels of protecting antibodies in the population in response to infection and/or immunization. Here we describe a simple, low cost, and high throughput Ni2+ magnetic bead immunoassay to detect human IgG reactive to Spike S1 RBD Receptor Binding Domain produced in Escherichia coli. A 6xHis-tagged Spike S1 RBD was expressed in E. coli and purifed by afnity chromatography. The protein was mobilized on the surface of Ni2+ magnetic beads and used to investigate the presence of reactive IgG in the serum obtained from pre-pandemic and COVID-19 confrmed cases. The method was validated with a cohort of 290 samples and an area under the receiver operating characteristic curve of 0.94 was obtained. The method was operated with>82% sensitivity at 98% specifcity and was also able to track human IgG raised in response to vaccination with Comirnaty at>85% sensitivity. The IgG signal obtained with the described method was well-correlated with the signal obtained when pre fusion Spike produced in HEK cell lines was used as antigen. This novel low-cost and high throughput immunoassay may act as an important tool to investigate protecting IgG antibodies against SARS-CoV-2 in the human population.
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