Virus-like particle-based liquid phase blocking ELISA for evaluating the efficacy of O-type foot-and-mouth disease vaccines
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Updated: Jan 12, 2026
Detection of Neutralization-sensitive Epitopes in Antigens Displayed on Virus-Like Particle VLP-Based Vaccines Using a Capture Assay
Published on: February 10, 2022
Yun Zhang1,2, Tian Wei1,2, Mei Ren1,2
1State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730000, China.
Abstract:
Virus-like particles (VLPs), which closely mimic the structural and antigenic properties of native foot-and-mouth disease (FMD) virions while lacking infectious genetic material, provide a more economical solution by replacing inactivated viruses in liquid-phase blocking ELISA (LPBE) testing for FMD serodiagnosis and vaccine evaluation. In this study, a novel LPBE was developed by replacing inactivated antigens with serotype O foot-and-mouth disease virus (FMDV) VLPs expressed in Escherichia coli. Based on evaluation of sensitivity and specificity, its correlation with virus neutralization test (VNT) results in immunized animal sera, as well as the feasibility and broad applicability for clinical serum sample detection, was further analyzed. Validation showed that VLPs-LPBE achieved high specificity (98.75%) and sensitivity (97.02%). Notably, in quantifying VLP-induced antibodies, the correlation with VNT results (R2 = 0.6809, P < 0.0001) was significantly stronger than that of commercial-LPBE. Blind evaluation of 853 clinical serum samples from vaccinated subjects demonstrated excellent agreement between VLPs-LPBE and conventional LPBE, with a kappa coefficient (κ) of 0.896, an intraclass correlation coefficient (ICC) of 0.904, and the concordance rate of 95.8%. These results confirm the clinical reliability and applicability for serological monitoring. In conclusion, VLPs-LPBE provides a safe, economical, and reliable alternative method for the evaluation of FMD vaccines. It eliminates the biosafety risks associated with the handling of inactivated viruses while maintaining compatibility with existing monitoring workflows. KEY POINTS: • VLPs-based ELISA safely replaces inactivated virus, reducing costs while maintaining diagnostic accuracy. • Stronger correlation with neutralization tests enhances VLPs-vaccine evaluation reliability vs. commercial kits. • High clinical concordance validates workflow compatibility for large-scale serological monitoring.
Insights
Virus-like particles (VLPs) offer a safer and more cost-effective method for foot-and-mouth disease (FMD) diagnosis and vaccine evaluation, replacing inactivated viruses in liquid-phase blocking ELISA (LPBE) tests. This VLP-based LPBE demonstrates high accuracy and strong correlation with neutralization tests, ensuring reliable serological monitoring.
Area of Science:
- Veterinary Immunology
- Virology
- Biotechnology
Background:
- Traditional foot-and-mouth disease (FMD) serodiagnosis and vaccine evaluation rely on inactivated viruses in liquid-phase blocking ELISA (LPBE).
- Handling inactivated viruses poses biosafety risks and increases costs.
- Virus-like particles (VLPs) mimic native virions without infectious genetic material, offering a potential alternative.
Purpose of the Study:
- To develop and validate a novel LPBE using serotype O FMDV VLPs expressed in Escherichia coli.
- To assess the sensitivity, specificity, and correlation with virus neutralization tests (VNT) of the VLP-based LPBE (VLPs-LPBE).
- To evaluate the clinical applicability and reliability of VLPs-LPBE for large-scale serological monitoring.
Main Methods:
- Recombinant serotype O FMDV VLPs were produced in E. coli and used as antigens in LPBE.
- VLPs-LPBE performance was evaluated using sera from immunized animals and compared with VNT and commercial LPBE.
- Clinical serum samples (n=853) from vaccinated subjects were analyzed for agreement between VLPs-LPBE and conventional LPBE.
Main Results:
- VLPs-LPBE demonstrated high specificity (98.75%) and sensitivity (97.02%).
- A strong correlation was observed between VLPs-LPBE and VNT for quantifying VLP-induced antibodies (R² = 0.6809, P < 0.0001), outperforming commercial LPBE.
- Blind evaluation of clinical samples showed excellent agreement with conventional LPBE (kappa = 0.896, ICC = 0.904, concordance = 95.8%).
Conclusions:
- VLPs-LPBE is a safe, economical, and reliable alternative for FMD serodiagnosis and vaccine evaluation.
- This method eliminates biosafety concerns associated with inactivated viruses.
- VLPs-LPBE is suitable for clinical use and compatible with existing monitoring workflows, facilitating large-scale serological surveillance.
