Effect of Different Promoters on the Efficacy of DNA Vaccine Against Hepatitis C Virus

Hepatitis C is a global health problem which causes about 2.4 million deaths each year due to the absence of effective treatment or vaccine. DNA vaccine showed great results in small animals but its efficiency in human is reduced. Different strategies were used to improve the efficacy of DNA vaccine. In this study, the effect of different promoters on the efficacy of DNA vaccine was tested. We constructed DNA vaccines encoding NS3 and E1 proteins under the control different promoters; cytomegalovirus promoter, adenoviral promoters E1A and MLP. The effect of the different promoters on antigen expression and vaccine efficacy was measured. Our results showed that CMV has the highest transcription level of NS3 and E1 in HEK 293 cells. After mice immunization, we found that all constructs produced NS3 and E1 specific antibodies however plasmids with CMV promoter produced the highest antibody titer. We also examined the miRNA expression level in serum after immunization. We found a slight, not significant increase in mir-181, mir-21 and mir-296. These results showed that the promoter strength has great impact on the efficiency of the DNA vaccine. CMV promoter has been found to be stronger than adenoviral promoters.