Potential of a Bead-Based Multiplex Assay for SARS-CoV-2 Antibody Detection

Area of Science:

• Immunology
• Virology
• Diagnostic Assay Development

Background:

• Serological assays are crucial for understanding SARS-CoV-2 infection, epidemiology, and immune responses.
• Screening convalescent sera is vital for therapeutic and prophylactic applications.

Purpose of the Study:

• To evaluate the performance of a novel bead-based multiplex assay for SARS-CoV-2 antibody detection.
• To compare this assay against commercial ELISA tests and assess its reproducibility.
• To correlate serological findings with neutralizing antibody assays.

Main Methods:

• Simultaneous testing of IgG antibodies against SARS-CoV-2 antigens (spike, S1, S2, RBD, nucleocapsid) and other coronaviruses using a bead-based multiplex assay.
• Comparison with commercial ELISA tests using sera from 27 SARS-CoV-2 PCR-positive individuals.
• Assessment of assay reproducibility through repeated testing and correlation with neutralizing assays.

Main Results:

• Qualitative result concordance ranged from 78% to 96% compared to ELISA, varying by antigen.
• Repeated freeze-thaw cycles reduced assay signal intensity, but storage duration did not impact results.
• Up to 36% of sera showed positive neutralizing antibodies, aligning with multiplex and IgG ELISA findings.

Conclusions:

• The bead-based multiplex assay demonstrates good performance and concordance with established methods for SARS-CoV-2 antibody detection.
• The assay is reproducible and suitable for investigating immune responses and epidemiological patterns.
• Findings support the utility of this multiplex assay in clinical and research settings for SARS-CoV-2.