Establishment of indirect ELISA based on gD protein of porcine pseudorabies virus and its application in immune evaluation
The aim of this study is to establish a simple and accurate method for vaccine immune e-valuation of porcine pseudorabies virus.In this research,PRV-gD recombinant protein was ex-pressed from mammalian cell HEK-293F as coating antigen,and then the reaction conditions of gD-iELISA were optimized according to checkerboard titration method.The gD-iELISA was used to detect the antibody levels of 211 clinical pig serum samples and the consistency with the neu-tralizing antibody levels wasanalyzed.The results showed that the antigen coating concentration was 0.90 mg/L;the serum to be detected was diluted 1∶100 and incubated at 37 ℃ for 30 min;goat anti-pig IgG-HRP antibody was diluted 1∶55 000 and incubated at 37 ℃ for 30 min;TMB sub-strate was developed at 37 ℃ for 20 min.The method could detect 1∶6 400 diluted PRV positive serum.The results of CSFV,PRRSV,PCV-2,PEDV and FMDV positive sera were all negative by gD-iELISA,and there was no cross-reaction between the method and the above positive sera.The coincidence rate of gD-iELISA and commercial kits was 95.26%,and the intra-and inter-batch co-efficients of variation were both less than 10%.Correlation analysis showed that the correlation coefficient(r)between gD antibody level and neutralizing antibody level was significantly greater than that of gB antibody level,and the gD antibody level had a good linear relationship with the neutralizing antibody level.The results indicated that gD-iELISA was more suitable for vaccine im-mune evaluation of PRV than gB-iELISA.Therefore,the method will have a good prospect of ap-plication in the immunization control of the PRV.