RECOMBINANT ANTIGEN BASED RAPID SERO-DIAGNOSIS OF INFECTIOUS BURSAL DISEASE (IBD)

摘要

A yeast expressed recombinant VP2 antigen based latex agglutination test (LAI) was developed to measure the specific antibody in sera of chickens against Infectious bursal disease virus. Infectious bursal disease virus (IBDV), belonging to the family Birnaviridae, exhibits an immunosuppressive disease of young chicken characterized by severe depletion of B-lymphocytes in the bursa of Fabricius. The major immunogenic capsid gene VP2 was cloned and expressed from the yeast Saccharomyces cerevisiae. Serological diagnosis is commonly performed with Agar gel immunoprecipitation test (AGPT), virus neutralization (VN) or Enzyme linked immunosorbent assay (ELISA). The recombinant VP2 antigen based kit when tested against a panel of chicken serum samples proved to be more sensitive and specific than AGPT. The recombinant VP2 protein could be simpler and safer to produce in bulk from yeast system and have higher sensitivity and specificity as the target antigen is immunodominant and devoid of any non specific moieties as present in whole cell preparations. The test is extremely simple and novel and not labour intensive like VN and does not require a virology laboratory. The test also does not require the usage of sophisticated equipments like ELISA reader and the results are proved to be sensitive, specific and accurate as compared to ELISA. Moreover the test can be performed in the field conditions and the sensitized latex coated beads could be stored at 4°C for more than 4 months and at ambient temperature for a month without the loss of activity for both weakly and strongly positive samples. Key words: Infectious bursal disease virus- recombinant VP2 antigen-yeast expression -Latex agglutination test- diagnosis