Abstract: The purpose of this study was to establish an indirect ELISA method for the detection of gC protein antibody of new pseudorabies virus FJ-2012 strain, and then the method was used to detect the level of gC antibody in different pig farms. The gC of FJ-2012 strain was connected to pCzn1 vector, then the recombinant vector was transfected into Arctic express (DE3) competent cells. The expression product induced by IPTG was verified by SDS-PAGE and Western blot. The indirect ELISA method for detecting PRV gC antibody was established by matrix test, determination of critical value, specificity test, repeatability, and sensitivity test. two hundred and eighty sera samples from different pig farms were detected for PRV gC antibody. The results showed that the pCzn1 gC recombinant protein of FJ-2012 strain was successfully expressed in Arctic express (DE3). The optimal antigen coating concentration of the indirect ELISA method was 10 μg·mL^-1, and the optimal serum dilution ratio of sample was 1∶50. The critical value of OD_{650 nm} for negative and positive judgment were 0.406 and 0.438, and the critical value between 0.406 - 0.438 were judged as suspicious. Clinical test results showed that, the positive rates of PRV gC antibody and PRV gB antibody in 120 blind pig serum were 91.67% and 95.00% respectively. The general coincidence rate of these two antibodies testing results were 95.83%. The positive rate of PRV gC antibody in blood samples from pig farms with unstable PR was 96.25% (77/80), however the positive rate of PRV gC antibody in blood samples from pig farms with purified PRV was 78.75% (63/80). Therefore, the indirect ELISA method established in this study not only provides a specific, sensitive and stable tool for the detection of porcine serum antibody, but also lays a foundation for the serological investigation of variant PRV.

Key words: pseudorabies virus, gC envelope protein, enzyme linked immune sorbent assay