Quantification of SARS-CoV-2 neutralizing antibody by a pseudotyped virus-based assay

Area of Science:

• Virology
• Immunology
• Infectious Diseases

Background:

• Pseudotyped viruses offer a safe and versatile alternative to native viruses for research.
• Developing robust neutralization assays is critical for evaluating countermeasures against emerging viral threats like SARS-CoV-2.

Purpose of the Study:

• To establish a pseudotyped virus-based neutralization assay for SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) suitable for biosafety level 2 facilities.
• To demonstrate the assay's capability in discriminating protective agents from non-protective antibodies.

Main Methods:

• Production and titration of SARS-CoV-2 S pseudotyped virus using a vesicular stomatitis virus (VSV) system.
• Implementation of a neutralization assay to evaluate the potency of various inhibitors targeting viral attachment and entry.
• Utilizing serum samples, monoclonal antibodies, and fusion inhibitors for assay validation.

Main Results:

• The developed assay effectively distinguishes between protective and non-protective antibodies, unlike standard binding antibody tests.
• The protocol allows for the evaluation of diverse sample types, including human and animal sera, monoclonal antibodies, and small molecules.
• Potency data for candidate samples can be obtained within 2 days if pseudotyped virus stocks are pre-prepared.

Conclusions:

• A safe and efficient pseudotyped virus neutralization assay for SARS-CoV-2 has been successfully developed.
• This assay is a valuable tool for assessing the efficacy of potential therapeutics and understanding immune responses against SARS-CoV-2.
• The protocol's versatility supports the evaluation of a wide range of neutralizing agents in a BSL-2 setting.