Development of a recombinant protein-based dot-blot hybridization assay for the detection of antibody to chicken infectious bronchitis virus

Nucleocapsid (N) protein of infectious bronchitis virus (IBV), one of the viral structural proteins, induces strong antibody response in natural infection. In this study, a simple, recombinant N protein-based dot-blot test was developed to serologically examine chicken serum samples for the presence of IBV antibody. Initially, 72 serum samples were tested for the presence of IBV antibody using a commercial enzyme linked immunosorbent assay (ELISA) kit. Forty six IBV positive serum samples (group A) produced strong signals in the dot-blot assay. Seven negative serum samples (group B) produced weak but specific signals using the dot-blot assay in conjunction with Western blot analysis. The remaining 19 samples (group C) from IBV negative specific pathogen free (SPF) chickens did not produce visible signals using the dot-blot assay. In conclusion, the above results suggest that the dot-blot assay is a reliable, sensitive, and specific test for serological detection of IBV positive chickens.