A DNA vaccine encoding a codon-optimized human papillomavirus type 16 E6 gene enhances CTL response and anti-tumor activity

Cheng Tao Lin, Ya Chea Tsai, Liangmei He, Roanne Calizo, Hung Hsueh Chou, Ting Chang Chang, Yung Kuei Soong, Chien Fu Hung, Chyong Huey Lai

Research output: Contribution to journalArticlepeer-review


The HPV oncoproteins E6 and E7 are consistently expressed in HPV-associated cancer cells and are responsible for their malignant transformation. Therefore, HPV E6 and E7 are ideal target antigens for developing vaccines and immunotherapeutic strategies against HPV-associated neoplasms. Recently, it has been demonstrated that codon optimization of the HPV-16 E7 gene resulted in highly efficient translation of E7 and increased the immunogenicity of E7-specific DNA vaccines. Since vaccines targeting E6 also represent an important strategy for controlling HPV-associated lesions, we developed a codon-optimized HPV-16 E6 DNA vaccine (pNGVL4a-E6/opt) and characterized the E6-specific CD8+ T cell immune responses as well as the protective and therapeutic anti-tumor effects in vaccinated C57BL/6 mice. Our data indicated that transfection of human embryonic kidney cells (293 cells) with pNGVL4a-E6/opt resulted in highly efficient translation of E6. In addition, vaccination with pNGVL4a-E6/opt significantly enhanced E6-specific CD8 + T cell immune responses in C57BL/6 mice. Mice vaccinated with pNGVL4a-E6/opt are able to generate potent protective and therapeutic antitumor effects against challenge with E6-expressing tumor cell line, TC-1. Thus, DNA vaccines encoding a codon-optimized HPV-16 E6 may be a promising strategy for improving the potency of prophylactic and therapeutic HPV vaccines with potential clinical implications.

Original languageEnglish (US)
Pages (from-to)481-488
Number of pages8
JournalJournal of biomedical science
Issue number4
StatePublished - Jul 2006


  • DNA vaccines
  • E6
  • E7
  • Human Papillomavirus (HPV)

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology
  • Biochemistry, medical
  • Pharmacology (medical)


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