Original Article 35 Cloning and Expression of Gumboro VP2 Antigen in Aspergillus niger

Background: Infectious Bursal Disease Virus (IBDV) causes a highly immuno-suppressive disease in chickens and is a pathogen of major economic im-portance to the poultry industry worldwide. The VP2 protein is the major host-protective immunogen of IBDV and has been considered as a potential subunit vaccine against the disease. VP2 coding sequence was cloned in an inducible fungal vector and the protein was expressed in Aspergillus niger (A. niger). Methods: Aiming at a high level of expression, a multicopy AMA1-pyrG-based episomal construct driven by a strong inducible promoter, glaA, was prepared and used in transformation of A. niger pyrG- protoplasts. SDS-PAGE and western blot analysis was carried out to confirm the expression of the protein. Results: A number of pyrG+ positive transformants were isolated and the pres-ence of expression cassette was confirmed. Western blot analysis of one of the-se recombinant strains using monospecific anti-VP2 antibodies demonstrated the successful expression of the protein. The recombinant protein was also de-tected by serum obtained from immunized chicken. Conclusion: In the present study, we have generated a recombinant A. niger strain expressing VP2 protein intracellulary. This recombinant strain of A. niger may have potential applications in oral vaccination against IBDV in poultry industry