Construction and expression characteristics in vitro of human papillomavirus type 16 E7 suicidal DNA vaccine

Objective To construct the suicidal DNA vaccine of human papillomavirus type 16 E7 gene(HPV16),and explore the DNA vaccine expression characteristics in vitro and capacity of inducing the transfected cells into apoptosis.Methods HPV16 E7 gene cloned by PCR from pET32/E7 was inserted into the plasmid pSCA1 to construct the recombinant plasmid pSCA/E7,followed by identification with PCR,BamHⅠ and SmaⅠ digestion and sequencing.pSCA/E7 was then used to transfect BHK-21 cell line.The transient expression of HPV16 E7 gene was confirmed by immuno-fluorescent staining,and the apoptosis induced by pSCA/E7 was checked with TDTmediated dUTP nick end-labeling(TUNEL).Results The cloned E7 gene fragment was about 400 bp in length.PCR,restriction endonuclease digestion and sequence analysis revealed that the HPV16 E7 gene was cloned into the eukaryotic expression plasmid pSCA1 successfully.Immunofluorescent staining confirmed that the E7 gene could express in BHK-21 cell line.The BHK21 cells transfected with pSCA/E7 could be induced into apoptosis which was confirmed by TUNEL.Conclusion The results show that HPV16 E7 suicidal DNA vaccine can express in BHK-21 cell line,and induce the pSCA/E7 transfected cells into apoptosis.These findings may provide the foundation for exploring the therapeutic vaccine against HPV16-associated cervical cancer.