Development of a Cell-Based SARS-CoV-2 Pseudovirus Neutralization Assay Using Imaging and Flow Cytometry Analysis

Area of Science:

• Virology
• Immunology
• Infectious Diseases

Background:

• The COVID-19 pandemic necessitates accurate measurement of neutralizing antibodies to SARS-CoV-2.
• Existing methods for assessing antibody neutralization can be slow or complex.
• Rapid and reliable assays are crucial for vaccine efficacy assessment and therapeutic development.

Purpose of the Study:

• To develop and validate a rapid, user-friendly neutralization assay for SARS-CoV-2.
• To quantify functional neutralizing antibodies in patient serum samples.
• To provide a tool for faster diagnosis and treatment evaluation during pandemics.

Main Methods:

• Development of a vesicular stomatitis virus (VSV)-based pseudovirus neutralization assay.
• Utilized two distinct readout methods: live-cell imaging and flow cytometry.
• Optimized assay parameters including pseudovirus type and multiplicity of infection (MOI).

Main Results:

• The VSV-based assay successfully quantified varying levels of SARS-CoV-2 neutralization in patient sera.
• Assay results demonstrated strong correlation with established serological and surrogate neutralization assays.
• Both imaging and flow cytometry readouts yielded comparable 50% neutralization titer (NT50) values.

Conclusions:

• The developed VSV-based assay offers a rapid and efficient method for evaluating SARS-CoV-2 neutralizing antibody responses.
• In situ and high-throughput capabilities enable swift assessment critical for pandemic mitigation.
• This assay serves as a valuable tool for monitoring vaccine effectiveness and guiding therapeutic strategies.