Overlaid Lateral Flow Immunoassay for the Simultaneous Detection of Two Variant-Specific SARS-CoV-2 Neutralizing...

Area of Science:

• Immunology
• Biotechnology
• Infectious Diseases

Background:

• COVID-19 vaccines aim to induce neutralizing antibodies (NAbs-COVID-19) for protection against SARS-CoV-2.
• Monitoring NAbs-COVID-19 levels is crucial but often complex, requiring hospital visits.
• NAbs-COVID-19 efficacy can vary against different COVID-19 strains (e.g., Delta, Omicron) based on vaccine type.

Purpose of the Study:

• To develop a simultaneous detection method for NAbs-COVID-19 against distinct SARS-CoV-2 variants.
• To create an accessible and efficient immunoassay for monitoring vaccine-induced immunity.

Main Methods:

• Development of an overlaid lateral flow immunoassay (O-LFIA) for simultaneous detection.
• Utilized a competitive inhibition assay with two test lines (T-lines) on a single device.
• Immobilized Angiotensin-converting enzyme 2 (ACE2) on T-lines to capture remaining antigens.

Main Results:

• The O-LFIA achieved 50% inhibition concentrations (IC50) of 45.1 ng/mL for Delta and 53.6 ng/mL for Omicron variants.
• Demonstrated simultaneous detection of NAbs-COVID-19 against both Delta and Omicron strains.
• Validated the assay with animal and human serum samples, showing good agreement with standard methods.

Conclusions:

• The developed O-LFIA is a viable alternative for detecting NAbs-COVID-19 against multiple SARS-CoV-2 strains.
• This platform shows potential for commercialization and future advancements in COVID-19 immunity monitoring.