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Introduction: Bronchitis virus (IB) is an acute, highly contagious and infectious poultry virus worldwide, causing significant economic losses to the poultry industry. The aim of this study was to produce recombinant S1 protein IBV 793/B and evaluate its immunogenicity in chickens.
Materials and Methods: To evaluate the recombinant S1 protein of infectious bronchitis. First,the gene encoding S1 glycoprotein IBV 793 /B was cloned into the pTZ 57 vector and then cloned into the non-secretory expression vector pPICZB and expressed in yeast cells Pichia pastoris and recombinant protein was examined by SDS -PAGE, western blot, Atomic-force and TEM microscopes. Then Immunogenicity was evaluated in SPF chickens.
Results: The results showed that the recombinant S1 protein was about 62KDa, which was confirmed by Western blotting and ELISA. Microscopic examination of the virus-like structure identified as the primary and important requirement for vaccine candidates. Three times immunization with recombinant protein, with Montanide adjuvant and live vaccine were determined eliciting immune response. The groups that was receiving primer H120 vaccine had higher titers than the other groups. After challenge with an acute virus, immunization did not completely prevent virus replication in the tissues, causing damage to the trachea, loss of cilia, destruction of the epithelial cell, interstitial hemorrhage in the lung, non-infectious thrombus, and renal hyperemia and degeneration Epithelial cells. However, no mortality was observed in all groups tested after the challenge.
Conclusion: Although immunogenicity did not completely prevent virus replication and proliferation in the respiratory, gastrointestinal, and renal tissues and was associated with injury, but it prevented the chickens from death and made them resistant to the virus.
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