The regulation of foreign gene expression in Insect-Baculovirus Expression System is very complex. In this report, the effect of 5′-UTR in the expression of hGH gene in cultured Sf9 cells was examined. A 18 bp length...The regulation of foreign gene expression in Insect-Baculovirus Expression System is very complex. In this report, the effect of 5′-UTR in the expression of hGH gene in cultured Sf9 cells was examined. A 18 bp length in the end of 5′-UTR of hGH (human Growth Hormone, hGH) cDNA including a stem-loop structure was deleted by PCR. The truncated hGH cDNA, Δ1hGH was cloned in pFastBac1, named pFast-Bac-Δ1hGH. After transforming into E.coli. DH10Bac, which have a shuttle vetor-Bacmid, the Δ1hGH was integrated into Bacmid by site-specific transposition, and an expression vector, rBacmid-Δ1hGH DNA was acquired. By transfecting the cultured Sf9 cells with the recombinant expression vector DNA, pure recombinant virus, rAcV-Bac-Δ1hGH was obtained, and hGH gene was expressed. Immuno-blot and Chemiluminescent assay revealed that the expressed hGH had normal immunological activity, the ammount of hGH expression level in Sf9 cell supernatant infected with rAcV-Bac-Δ1hGH containing the truncated 5′UTR was four to five times higher than that infected with rAcV-Bac-hGH.展开更多
Recent improvement in the technologies for efficient delivery of DNA vaccines has renewed interest in the DNA-based vaccines. Several DNA-based vaccines against human enterovirus 71 (EV71), the causative agent for han...Recent improvement in the technologies for efficient delivery of DNA vaccines has renewed interest in the DNA-based vaccines. Several DNA-based vaccines against human enterovirus 71 (EV71), the causative agent for hand, foot and mouth disease (HFMD) have been developed. Here we examined the potential of improving the vaccines by inserting the EV71 5’ untranslated region (5’ UTR) containing the full length internal ribosome entry site (IRES) sequence to the EV71 VP1-based DNA vaccine constructs. Four vaccine constructs designated as 5’ UTR-VP1/EGFP, VP1/EGFP, 5’ UTR-VP1/pVAX and VP1/pVAX, were designed using the pEGFP-N1 and pVAX-1 expression vectors, respectively. Transfection of Vero cells with the vaccine constructs with the 5’-UTR (5’-UTR-VP1/EGFP and 5’ UTR-VP1/pVAX) resulted in higher percentages of cells expressing the recombinant protein in comparison to cells transfected with vectors without the 5’-UTR (67% and 57%, respectively). Higher IgG responses (29%) were obtained from mice immunized with the DNA vaccine construct with the full length 5’ UTR. The same group of mice when challenged with life EV71 produced significantly higher neutralizing antibody (NAb) titers (>5-fold). These results suggest that insertion of the EV71 5’ UTR sequence consisting of the full length IRES to the EV71 DNA vaccine constructs improved the efficacy of the constructs with enhanced elicitation of the neutralizing antibody responses.展开更多
文摘The regulation of foreign gene expression in Insect-Baculovirus Expression System is very complex. In this report, the effect of 5′-UTR in the expression of hGH gene in cultured Sf9 cells was examined. A 18 bp length in the end of 5′-UTR of hGH (human Growth Hormone, hGH) cDNA including a stem-loop structure was deleted by PCR. The truncated hGH cDNA, Δ1hGH was cloned in pFastBac1, named pFast-Bac-Δ1hGH. After transforming into E.coli. DH10Bac, which have a shuttle vetor-Bacmid, the Δ1hGH was integrated into Bacmid by site-specific transposition, and an expression vector, rBacmid-Δ1hGH DNA was acquired. By transfecting the cultured Sf9 cells with the recombinant expression vector DNA, pure recombinant virus, rAcV-Bac-Δ1hGH was obtained, and hGH gene was expressed. Immuno-blot and Chemiluminescent assay revealed that the expressed hGH had normal immunological activity, the ammount of hGH expression level in Sf9 cell supernatant infected with rAcV-Bac-Δ1hGH containing the truncated 5′UTR was four to five times higher than that infected with rAcV-Bac-hGH.
文摘Recent improvement in the technologies for efficient delivery of DNA vaccines has renewed interest in the DNA-based vaccines. Several DNA-based vaccines against human enterovirus 71 (EV71), the causative agent for hand, foot and mouth disease (HFMD) have been developed. Here we examined the potential of improving the vaccines by inserting the EV71 5’ untranslated region (5’ UTR) containing the full length internal ribosome entry site (IRES) sequence to the EV71 VP1-based DNA vaccine constructs. Four vaccine constructs designated as 5’ UTR-VP1/EGFP, VP1/EGFP, 5’ UTR-VP1/pVAX and VP1/pVAX, were designed using the pEGFP-N1 and pVAX-1 expression vectors, respectively. Transfection of Vero cells with the vaccine constructs with the 5’-UTR (5’-UTR-VP1/EGFP and 5’ UTR-VP1/pVAX) resulted in higher percentages of cells expressing the recombinant protein in comparison to cells transfected with vectors without the 5’-UTR (67% and 57%, respectively). Higher IgG responses (29%) were obtained from mice immunized with the DNA vaccine construct with the full length 5’ UTR. The same group of mice when challenged with life EV71 produced significantly higher neutralizing antibody (NAb) titers (>5-fold). These results suggest that insertion of the EV71 5’ UTR sequence consisting of the full length IRES to the EV71 DNA vaccine constructs improved the efficacy of the constructs with enhanced elicitation of the neutralizing antibody responses.
