Expression of the spike protein and its S1 subunit of infectious bronchitis virus using three expression systems.

摘要

Infectious bronchitis is one of most economically important diseases in the poultry industry. Developing an accurate and rapid test to identify the serotype of field strains has been important for the industry to effectively control outbreaks of the disease. To achieve this goal, the S1 subunit of spike (S) protein gene and the whole S protein gene of Arkansas 99 strain (Ark99) (a member of the most common strain) of infectious bronchitis virus were constructed and expressed in adenovirus, yeast, and baculovirus expression systems. In the adenovirus expression system, four different constructs of recombinant adenoviruses that carried the S1 or the S gene were successfully engineered. However, the S1 or the S protein could not be detected from the extracted cytosol and membrane proteins from infected 293 (a human cell line) and LMH cells (a chicken cell line).{09}In the yeast expression system, four different constructs of intergrated yeast that carried the S1 gene were successfully engineered. However, the S1 protein was not detected from the cultured medium, cytosol and membrane of constructed yeast cells using Western blot analysis. In the baculovirus system, two different constructs of recombinant baculovirus that carried the S1 or S gene were successfully engineered. Transcripts of the S1 and the S genes were detected using the reverse transcription polymerase chain reaction. The S1 and S proteins were both detected as soluble and insoluble forms in insect cells infected with the baculovirus recombinants. Also, both modified and unmodified proteins were produced. Most importantly, our results revealed that the recombinant S protein was only partially specific to the Ark99 serotype of IBV, and the recombinant S1 protein was highly specific. The results suggested that the expressed S1 or S protein, especially S1 protein, could be used as an antigen in an ELISA test to detect the presence of Ark 99 serotype antibody in infected flocks. This study also shows that baculovirus is an excellent system to express the glycoprotein of viruses originated from chickens.