Development of an enzyme-linked immunosorbent assay for detection of antibodies against infectious bursal disease virus based on a version of the recombinant viral protein 2

Infectious bursal disease virus (IBDV) is the etiological agent of a highly contagious and immunosuppressive disease in chickens. In poultry farms, the level of anti-IBDV antibodies of numerous serum samples must be monitored using fast and simple methodologies. Therefore, the aim of this study was to develop an enzyme-linked immunosorbent assay (ELISA), in an indirect format, using a version of mature viral protein 2 (VP2) of IBDV as coating agent. This recombinant fusion protein (His-VP2) was expressed at high levels in Escherichia coli. Bacterial inclusion bodies containing His-VP2 were successfully recovered using a simple, inexpensive and efficient method, a further purification of recombinant protein by affinity chromatography using immobilized metal chelates being unnecessary. After the VP2-ELISA was optimized, its performance was evaluated using preanalyzed sera from uninfected specific pathogen-free chickens and broilers vaccinated against IBDV in poultry farms, using a commercial ELISA kit. Based on these results, the developed assay proved to be sensitive, specific and in high agreement with the kit available on the market. In addition, the in-house ELISA demonstrated to be reproducible by intra-assay and inter-assay variability studies. In conclusion, VP2-ELISA could be an efficient and low-cost alternative diagnostic method to detect antibodies to IBDV in the poultry industry.