An indirect ELISA of classical swine fever virus based on quadruple antigenic epitope peptide expressed in E.coli.

In this study, a synthesized quadruple antigenic epitope gene region of the classical swine fever virus (CSFV) E2 glycoprotein was expressed in E. coli to a obtain target protein. This target protein was used as a coating antigen to establish an indirect ELISA for specifically detecting anti-CSFV antibodies in serum samples from pigs. The P/N cut-off value of this assay was 1.92 by receiver operating characteristic curve (ROC) analysis based on 30 negative sera and 80 positive samples. The test gave 97.5% sensitivity and 96.7% specificity compared with the indirect hemagglutination (IHA) test. The inter-assay and intra-assay coefficients of variation (CVs) for 16 sera were both ≤6.8%. No cross-reactivity between the coating antigen and anti-bovine viral diarrhoea virus (BVDV) antibodies was observed.