Development of a sensitive and specific xMAP assay for detection of antibodies against infectious laryngotracheitis and bronchitis viruses

BACKGROUND: A serological method to simultaneously detect antibodies against infectious laryngotracheitis virus (ILTV) and infectious bronchitis virus (IBV) is imperative for the differential diagnosis and evaluation of antibodies titers after vaccination. METHOD: The microspheres coated with purified recombinant glycoprotein D (gD) of ILTV or nucleocapsid (N) protein of IBV were incubated with serum samples. The simultaneous quantification of ILTV and IBV antibodies were achieved through the interrogation of microspheres by Luminex 200 detection system. . RESULTS: This xMAP detection demonstrated no nonspecific reactions with avian influenza virus (AIV), avian leukosis virus (ALV), newcastle disease virus (NDV), and Marek's disease virus (MDV). The results also demonstrated that the xMAP assay was four times more sensitive than the enzyme-linked immunosorbent assay (ELISA) for ILTV detection and two times more sensitive for IBV detection. A total of 90 chicken serum samples from a chicken farm were tested by xMAP and ELISA assays. The results showed that the coincidence rates were 84.44 and 100% for ILTV and IBV detection, respectively. CONCLUSION: This study exhibited an opportunity for the differential diagnosis through simultaneous detection of multiplex antibodies in serum and can be used for the multiplex antibodies evaluation after vaccination.