Construction, Expression and Evaluation of Recombinant VP2 Protein for serotype-independent Detection of FMDV Seropositive Animals in Egypt

Sci Rep. 2019 Jul 12;9(1):10135. doi: 10.1038/s41598-019-46596-9.

Abstract

Foot-and-mouth disease virus (FMDV) is one of the most devastating viral pathogens of cloven-hoofed animals. The detection of antibodies (Ab) against FMDV structural proteins (SP) using virus neutralization test (VNT) and liquid-phase blocking ELISA (LPBE) is the standard procedure in use for monitoring seroconversion in animals post vaccination, the prevalence of infection-surveillance, proving clinical cases and seronegative status of FMDV-free/naïve-animals prior transportation. However, due to variations within SP of FMDV serotypes, each serotype-specific Ab should be detected separately which is laborious and time-consuming. Accordingly, it is crucial to develop a sensitive, rapid, and accurate test capable of detecting FMDV-specific Ab, regardless its serotype. This study describes the heterologous expression of VP2 protein in E. coli, and its evaluation as a capture antigen in a simple indirect ELISA for serotype-independent detection of anti-FMDV Ab. Sequence analysis revealed that the VP2-coding sequence is considerably conserved among FMDV serotypes. The recombinant VP2 (rVP2), a 22 kDa polypeptide, was purified to near homogeneity by affinity chromatography under native conditions. Immunoreactivity of the rVP2 was confirmed by using a panel of positive sera including sera from animals vaccinated with the local trivalent vaccine and guinea pig FMDV antiserum, which is routinely used as tracing/detecting Ab in LPBE testing. The results obtained from the VP2-based ELISA were comparable to those determined by VNT and LPBE standard diagnostic assays. Specificity and sensitivity of rVP2 in capturing anti-FMDV Ab were 98.3% and 100%, respectively. The developed VP2-ELISA is proved reliable and time-efficient assay for detection of FMDV seropositive animals, regardless the FMDV serotype that can be implemented in a combination with VNT and/or LPBE for rapid diagnosis of an ongoing FMDV infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Viral / genetics
  • Capsid Proteins / genetics
  • Capsid Proteins / immunology*
  • Capsid Proteins / metabolism
  • Cattle
  • Ägypten
  • Enzyme-Linked Immunosorbent Assay / methods
  • Enzyme-Linked Immunosorbent Assay / standards
  • Female
  • Foot-and-Mouth Disease / diagnosis
  • Foot-and-Mouth Disease / virology*
  • Foot-and-Mouth Disease Virus / genetics
  • Foot-and-Mouth Disease Virus / immunology*
  • Immune Sera
  • Mice, Inbred BALB C
  • Protein Engineering / methods
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology*
  • Recombinant Proteins / metabolism
  • Serogroup
  • Viral Vaccines / immunology

Substances

  • Antigens, Viral
  • Capsid Proteins
  • Immune Sera
  • Recombinant Proteins
  • VP2 protein, Foot-and-mouth disease virus
  • Viral Vaccines