Recombinant adenovirus with human indoleamine-2,3-dioxygenase and hepatitis B virus preS was constructed and expressed in HepG2 cells.

Background: Indoleamine-2,3-dioxygenase (IDO) is proven to suppress hepatitis B virus (HBV) specific immune response and depletion of IDO may be a useful approach for HBV therapy. To test this concept, we constructed recombinant adenovirus with human IDO and HBV preS, which would form the basis for future in vivo experiments.

Methods: The fragment of human IDO and HBV preS cDNA were subcloned into multiple cloning sites in an adenoviral vector system containing two cytomegalovirus (CMV) promoters. Recombination was conducted in the Escherichia coli BJ5183. The recombinant adenovirus containing hIDO gene and HBVpreS gene was packaged and amplified in 293 cells. Integration was confirmed by polymerase chain reaction as well as the quantification of viral titers. HepG2 cells were infected with the recombinant adenovirus and mRNA and protein specific for hIDO and HBVpreS was detected by RT-PCR and Western blotting respectively.

Results: The recombinant adenovirus was produced successfully. Its titer was 2.5 × 10(9) efu/ml. IDO and HBVpreS mRNA as well as the encoded proteins could be found in transfected HepG2 cells, but not in control HepG2 cells.

Conclusion: The transfer of hIDO-HBVpreS with double-promoter adenoviral vector was efficient. The recombinant adenovirus with hIDO and HBV preS would provide the experimental basis for future studies.