Recombinant UL16 antigen-based indirect ELISA for serodiagnosis of duck viral enteritis.

In this study, a recombinant fusion antigen of duck enteritis virus (DEV) UL16 protein was expressed in Escherichia coli Rossetta (DE3). This target protein was used as a coating antigen to establish an indirect ELISA for detecting anti-DEV antibodies in serum samples from ducks. In the optimal method for the UL16-ELISA, the fusion protein was coated at 1.25μg/ml and duck serum samples were diluted at 1:160. The endpoint cut-off value of this assay was 0.598. The inter-assay and intra-assay coefficients of variation (CVs) were both lower than 10%. There was no cross-reaction with duck positive sera of either DHBV, DHV, RA, E. coli, Salmonella anatum, H5N1 or DSHDV. The assay was applied successfully to examine the suspected duck serum samples and showed 95.5% (73/76) identity with the serum neutralization test (SNT). The results showed that recombinant DEV UL16 protein could be used as a coating antigen and the developed UL16-ELISA approach was rapid, specific, sensitive and repetitive.