Development of a competitive chemiluminescence immunoassay using a monoclonal antibody recognizing 3B of foot-and-mouth disease virus for the rapid detection of antibodies induced by FMDV infection

Wei Liu,Guanglei Zhang,Sicheng Yang,Huiyun Chang,Junhui Li,Huihui Yang,Sudan Ge,Zhan Gao,Junjun Shao

doi:10.1186/s12985-021-01663-4

Abstract

BackgroundFoot-and-mouth disease (FMD) is a devastating animal disease. Anti-non-structural protein (NSP) antibody detection is very important for confirming suspected cases, evaluating the prevalence of infection, certifying animals for trade and controlling the disease.MethodsIn this study, a competitive chemiluminescence immunoassay (3B-cCLIA) was developed for the rapid detection of antibodies against NSPs in different species of livestock animals using the monoclonal antibody (mAb) 9E2 as a competitive antibody that recognizes NSP 3B.ResultsThe cut-off value (50%), diagnostic sensitivity (Dsn) (97.20%, 95.71%, and 96.15%) and diagnostic specificity (Dsp) (99.51%, 99.43%, and 98.36) of the assay were estimated by testing a panel of known-background sera from swine, cattle and sheep, respectively. The accuracy rate of the 3B-cCLIA was further validated and subsequently compared with that of two commercial diagnostic kits. The early diagnostic results showed that antibodies recognizing NSPs developed later (approximately 1–2 days) than antibodies recognizing structural proteins. Furthermore, anti-NSP antibody presence in animals vaccinated multiple times (false positives), especially cattle and sheep, was confirmed, and the false-positive rate increased with the number of vaccinations.ConclusionsThese results indicate that the 3B-cCLIA is suitable for the rapid detection of antibodies against FMDV NSP 3B in a wide range of species.

Highlights

Foot-and-mouth disease (FMD) is a devastating animal disease
The detection of antibodies against non-structural protein (NSP) has become a widely preferred and applied diagnostic method for differentiation between FMDV-infected and vaccinated animals (DIVA) that is helpful in identifying subclinical infections, evaluating the prevalence of infection and controlling the disease [8] because a series of purifying techniques remove the majority of NSPs from the inactivated vaccine during production [3, 9]
Serum samples from infected animals: The collection of 107 serum samples from swine infected with FMD virus (FMDV) A/GDMM/2013 or O/Mya98 at 7–25 days post infection was carried out in the Animal Biological Safety Level 3 (ABSL-3) Laboratory at Lanzhou Veterinary Research Institute (Lanzhou, China); 70 serum samples were collected from cattle infected with FMDV (A/ GDMM/2013 or O/Mya98) at 8–20 dpi, and 52 serum samples were collected from sheep with clinical symptoms in the field, which tested as NSP positive using two commercial diagnostic kits (3ABC-bELISA and PrioCHECK FMDV NSP ELISA)

Summary

Introduction

Foot-and-mouth disease (FMD) is a devastating animal disease. Anti-non-structural protein (NSP) antibody detection is very important for confirming suspected cases, evaluating the prevalence of infection, certifying animals for trade and controlling the disease. Foot-and-mouth disease (FMD) is a highly contagious and economically damaging viral disease that affects cloven-hoofed animals. Vaccination with inactivated vaccines creates other issues, such as the differentiation between FMDV-infected and vaccinated animals (DIVA) and the creation of carrier animals that shed the virus [6, 7]. The detection of antibodies against NSPs has become a widely preferred and applied diagnostic method for DIVA that is helpful in identifying subclinical infections, evaluating the prevalence of infection and controlling the disease [8] because a series of purifying techniques remove the majority of NSPs from the inactivated vaccine during production [3, 9]

Methods

Results

Conclusion