title: A DNA vaccine constructed with human papillomavirus type 16 (HPV16) E7 and E6 genes induced specific immune responses.
abstract: OBJECTIVE
  Cervical cancer is found highly associated with human papillomaviruses type 16 (HPV16). HPV16 E6 and E7 oncogenes are important transforming genes which have become the main focus of anti-cervical cancer therapy. In this study, a recombinant DNA vaccine candidate, termed HPV16-DNA-E6E7, constructed with HPV16 E7 and E6 genes was generated and used to against HPV16-induced tumors.
  
  
  METHODS
  We inserted an E7 DNA fragment into E6 gene to produce a recombinant gene (E6E7-DNA). The E6E7-DNA gene was inserted into a mammalian expression vector, pcDNA 3.1+, to construct the DNA vaccine candidate. Animals (C57BL/6 mice) were immunized with the vaccine candidate with various concentrations (50 microg, 100 microg or 200 microg, respectively), and cytotoxicity measurement and tumor protection assay were carried out to examine the immunological effects of the vaccine candidate.
  
  
  RESULTS
  Immunization of with HPV16-E6E7-DNA induced HPV16-specific immune response and also conveyed protection against TC-1 induced tumor in vivo. A survival rate (90%) after 45 days of tumor challenge was observed. The animals injected with a higher dosage of the vaccine (200 microg) exhibited prolonged survival duration of more than 55 days. No transforming activity of the vaccine candidate was detected, as determined by focus formation and degradation of endogenous p53.
  
  
  CONCLUSIONS
  Our results demonstrated that the HPV16-E6E7-DNA compound might become a candidate for HPV16 precautionary and immunotherapy.
authors.affiliation: Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, PR China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Yan
authors.forename: Ying-Kit
authors.initials: YK
authors.lastname: Cheung
authors.forename: Samuel Chak-Sum
authors.initials: SC
authors.lastname: Cheng
authors.forename: Xian-Hua
authors.initials: XH
authors.lastname: Wang
authors.forename: Meng
authors.initials: M
authors.lastname: Shi
authors.forename: Mei-Haob
authors.initials: MH
authors.lastname: Hu
authors.forename: Xie
authors.initials: X
authors.lastname: Yong
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000276:immunology; D041702:BALB 3T3 Cells; D019556:COS Cells; D002472:Cell Transformation, Viral / Q000235:genetics; D002522:Chlorocebus aethiops; D004279:DNA, Viral / Q000235:genetics / Q000276:immunology; D005260:Female; D006801:Humans; D008546:Melanoma, Experimental / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000276:immunology*; D050725:Papillomavirus E7 Proteins; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology
chemical_list: D000914:Antibodies, Viral; D004279:DNA, Viral; C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D012097:Repressor Proteins; D019444:Vaccines, DNA; C059731:oncogene protein E7, Human papillomavirus type 16