Study On HBV Post - Transcriptional Regulating Function Of A Sequence And Its Applications In Nucleic Acid Vaccine

The hepatitis B virus post-transcriptional regulatory element is a regulatory region residing in the HBV genome. It regulates the expression of gene on the level of posttranscription. Some nuclear proteins bind to the element and help mRNA export from nuclus.Furthermore,some proteins induced by cytokines suppress the process through binding to dispersed sites of HPRE. The expression of HBV genome is controlled by this mechanism.Taenia solium cysticercus is the larva of T. solium. It causes Taenia solium cysticercosis when man were infected with cysticercus of Taenia solium .Several approaches are being used towards the Taenia solium cysticercosis vaccine,including vaccines using native and recombinant antigens from whole Taenia solium cysticercus,protein subunit vaccines,and DNA vaccines. DNA vaccine developing from nineties can induces all-round immunoreaction and have merits of no-toxin, deposition and transportation. But it's potential danger is the focus of attention. Some researches have proved that DNA vaccine of Taenia solium cysticercosis has a well protection.Our study used luciferase as a reporter gene and cloned the HPRE element and the element defaulting some subelement into the downstream of the reporter gene. And we conceived the following vectors which can expression in mammalian cells: pcDNA3.0-luc, pcDNA3.0-luc-HPRE, pcDNA3.0-luc-HPREβ₁β₂ pcDNA3.0-luc--HPREαβ₂及pcDNA3.0-luc-HPREαβ₁.Then these vectors were transfected into mammalian cells.We used IFN-αas a inducer which can abduct proteins suppressing the mechanism of HPRE. The expression of luciferase was detected by luciferase assay system before and after added IFN-α. The result demonstrated that the change of LUC(luciferase) expression was unconspicuous when default theβ₂.In other words,theβ₂ element plays a important part in the suppression function of HPRE.We cloned the HPRE element defaulting theβ₂ into the DNA Taenia solium cysticercosis vaccine pPCV.Mice were immunized by the new conceived vaccine pPCV-HP.We assayed antibody by ELISA,then assaulted mice with Taenia solium cysticercus two weeks later and anatomized mice and observed cysticercus three months later. It showed that the protective rate of vaccine pPCV-HP was 8% higher than vaccine pPCV.Environmental samples were picked up and we analyzed the tissue distribution,integration into host genome and environmental transfer of the vaccine. We observed that the plasmid was cleared in most tissues. No integration and environmental transfer were find. In a word,the new conceived vaccine have high protective rate and biosafety.