Abstract: The purified S1 gene fragment of the prevailing Avian infectious bronchitis virus (IBV), from LC2 strain isolated from Shandong Province, was inserted into the eukaryotic expression plasmid pPIC9K. The recombination yeast pPIC9K-S1-GS115 was constructed, and was identified by MD/MM plates,G418 and PCR. The expression induced by pPIC9K-S1-GS115 with 0.5% methanol was identified by SDS-PAGE and Western blot, which was specific with the reference IBV serum. Further more, SPF chickens could be detected positive after being immunized by the expression and recombination yeast. The results suggested that recombinant expression vector was successfully constructed, and the protein was successfully expressed against IBV, which would play an important role in IBV diagnose and vaccine．

Key words: IBV, S1 gene, Pichia pastoris, expression, immunogenicity