BMC Veterinary Research (Jan 2020)

A neutralizing monoclonal antibody-based competitive ELISA for classical swine fever C-strain post–vaccination monitoring

  • Lihua Wang,
  • Shijiang Mi,
  • Rachel Madera,
  • Llilianne Ganges,
  • Manuel V. Borca,
  • Jingqiang Ren,
  • Chase Cunningham,
  • Ada G. Cino-Ozuna,
  • Hongwei Li,
  • Changchun Tu,
  • Wenjie Gong,
  • Jishu Shi

DOI
https://doi.org/10.1186/s12917-020-2237-6
Journal volume & issue
Vol. 16, no. 1
pp. 1 – 8

Abstract

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Abstract Background Virus neutralization test (VNT) is widely used for serological survey of classical swine fever (CSF) and efficacy evaluation of CSF vaccines. However, VNT is a time consuming procedure that requires cell culture and live virus manipulation. C-strain CSF vaccine is the most frequently used vaccine for CSF control and prevention. In this study, we presented a neutralizing monoclonal antibody (mAb) based competitive enzyme-linked immunosorbent assay (cELISA) with the emphasis on the replacement of VNT for C-strain post–vaccination monitoring. Results One monoclonal antibody (6B211) which has potent neutralizing activity against C-strain was generated. A novel cELISA was established and optimized based on the strategy that 6B211 can compete with C-strain induced neutralizing antibodies in pig serum to bind capture antigen C-strain E2. By testing C-strain VNT negative pig sera (n = 445) and C-strain VNT positive pig sera (n = 70), the 6B211 based cELISA showed 100% sensitivity (95% confidence interval: 94.87 to 100%) and 100% specificity (95% confidence interval: 100 to 100%). The C-strain antibody can be tested in pigs as early as 7 days post vaccination with the cELISA. By testing pig sera (n = 139) in parallel, the cELISA showed excellent agreement (Kappa = 0.957) with VNT. The inhibition rate of serum samples in the cELISA is highly correlated with their titers in VNT (r 2 = 0.903, p < 0.001). In addition, intra- and inter-assays of the cELISA exhibited acceptable repeatability with low coefficient of variations (CVs). Conclusions This novel cELISA demonstrated excellent agreement and high level correlation with VNT. It is a reliable tool for sero-monitoring of C-strain vaccination campaign because it is a rapid, simple, safe and cost effective assay that can be used to monitor vaccination-induced immune response at the population level.

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