Development of recombinant subunit vaccine and monoclonal antibody based diagnostic test for infectious bursal disease in chickens

Abstract

Infectious bursal disease (IBD) also known as Gumboro disease after the geographical location of the first outbreak in 1962 is an acute, highly contagious disease of young chickens caused by Infectious bursal disease virus (IBDV), characterized by immunosuppression and mortality generally at 3-6 weeks of age. The aim of this work was to develop a simple and reliable detection method and to explore the potential of vaccination as an intervention strategy against IBDV. The major structural protein VP2 of IBD virus was selected as host-protective antigen of immunoprophylactic studies. It contains different independent epitopes responsible for the induction of neutralizing antibody. In this study, we report the efficacy of an immunodominant fragment of VP2 which induces both humoral and cellular immunity against infectious bursal disease. In order to facilitate the quantification of antibodies and to screen a large number of serum samples, an ELISA based on this recombinant VP252- 417 protein was developed. The anti IBDV IgY antibodies present in field sera were assessed and analyzed. The IgY-ELISA based on recombinant VP252-417 protein recommended the possible use of this protein in the serodiagnosis of IBD. I n o rder to prolong the protective effect induced by protein immunization, the prospet of utilizing DNA vaccines for long-term in vivo antigen expression was explored. P resently, problems in the immuno-diagnosis are the specificity to detect IBDV antigen, stability of diagnostic lines, cost of assays, time and manpower associated with use of ELISA kit and PCR etc. Two monoclonal antibodies namely 3A11A2 and 1C7F12 with better sensitivity were selected for validating capture ELISA. The efficiency of sandwich ELISA was analyzed with IBDV infected bursal samples and used uninfected bursal sample as control. The evaluated results of sandwich assay showed 100% sensitivity in the data obtained from experimental test groups. newline newline newline