A simple and safe antibody neutralization assay based on polio pseudoviruses

Area of Science:

• Virology
• Immunology
• Vaccinology

Background:

• Evaluating inactivated poliovirus vaccine (IPV) immunogenicity traditionally requires live wild poliovirus strains.
• Handling live poliovirus necessitates high-level biocontainment facilities (BSL-3), posing safety and logistical challenges.

Purpose of the Study:

• To develop a safe, alternative assay for assessing IPV immunogenicity without using live viruses.
• To establish and validate a pseudovirus-based neutralization test (pNT) for polio vaccine evaluation.

Main Methods:

• Constructed pseudovirions (Mahoney, MEF-1, Saukett) with luciferase reporter genes.
• Developed and validated a pseudovirus-based neutralization test (pNT).
• Compared pNT results with conventional neutralization tests (cNT) using serum samples from an sIPV vaccine clinical trial.

Main Results:

• pNT demonstrated high specificity and reproducibility.
• A strong correlation (r > 0.82, p < 0.0001) was observed between pNT and cNT for all IPV types.
• pNT showed approximately four-fold higher Geometric Mean Titer (GMT) values, indicating enhanced sensitivity compared to cNT.

Conclusions:

• The pseudovirus-based neutralization test (pNT) is a safe, rapid, and sensitive quantitative assay.
• pNT holds significant potential as an alternative method for evaluating polio vaccine potency.
• This assay circumvents the need for live virus handling, improving safety and accessibility in vaccine immunogenicity testing.