Comparison of Four SARS-CoV-2 Neutralization Assays

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Neutralizing antibodies are crucial for protection against SARS-CoV-2.
• Standardized and validated assays are needed to compare vaccine-induced immune responses.

Purpose of the Study:

• To compare the performance and reproducibility of four different in vitro SARS-CoV-2 neutralization assays.
• To assess the correlation between different assay formats and S-protein binding antibody levels.

Main Methods:

• Comparison of four SARS-CoV-2 neutralization assays: focus forming assay, TCID50 assay (using replication-competent virus), and two pseudotyped virus assays (lentiviral and VSV-based).
• Utilized a consistent set of patient samples across all assays.
• Measured neutralization titers and SARS-CoV-2 S-protein binding antibody titers via ELISA.

Main Results:

• All four evaluated SARS-CoV-2 neutralization assays demonstrated robustness and high reproducibility.
• Significant correlations were observed between neutralization titers obtained from the different assays.
• Neutralizing antibody titers correlated well with SARS-CoV-2 S-protein specific antibody titers measured by ELISA.

Conclusions:

• Commonly employed SARS-CoV-2 neutralization assays are reliable for measuring antibody responses.
• Results from different SARS-CoV-2 neutralization assay platforms are comparable, facilitating inter-study comparisons and vaccine efficacy assessments.