[Effect of modified NDV F48E9 strain HN gene and in vitro expression of its DNA vaccine].

Improving expression of antigen is critical to the immunogenicity of DNA vaccines. To achieve this goal, we modified the NDV F48E9 strain HN gene by optimizing the condon usage and inserting the secretary leader sequence [A/Goose/Guangdong/1/96 (H5N1) HA gene, Accession No. AF144305]. The HN gene modified and knocked the signal peptide off were named SoptiHN and optiHN. The three sequence: SoptiHN, optiHN and the NDV F48E9 strain HN gene were inserted into the vector pVAX1 and vector pVAX1-CpG including CpG-ODN sequence respectively. Then we got six recombinant plasmids: pV-SoptiHN, pVC-SoptiHN, pV-optiHN, pVC-optiHN, pV-HN and pVC-HN. By optimizing condon usage in transiently transfected 293T cells, expression levels of HN gene were higher from the codon-optimized gene than the counterpart. Moreover, both optimization of condon usage and addition of signal peptide could improve expression of HN gene in vitro.