Optimal induction of HPV DNA vaccine-induced CD8+ T cell responses and therapeutic antitumor effect by antigen engineering and electroporation.
Since human papillomavirus (HPV) E6 and E7 are promising tumor antigens, we engineered E6 and E7 antigens to generate an optimal HPV DNA vaccine by codon optimization (Co), fusion of E6 and E7, addition of a tissue plasminogen activator (tpa) signal sequence, addition of CD40 ligand (CD40L) or Fms-like tyrosine kinase-3 ligand (Flt3L). The resulting constructs were investigated in terms of their antitumor activity as well as induction of HPV-specific CD8(+) T cell responses. When E6(Co) and E7(Co) were fused (E67(Co)), CD8(+) T cell responses specific for E6 or E7 antigen decreased, but the preventive antitumor effect rather improved, demonstrating the importance of broad immunity. Interestingly, Flt3L-fused HPV DNA vaccine exhibited stronger E6- and E7-specific CD8(+) T cell responses as well as therapeutic antitumor effect than that of CD40L linked HPV DNA vaccine. Finally, the optimal construct, tFE67(Co), was generated by including tpa signal sequence, Flt3L, fusion of E6 and E7, and codon optimization, which induces 23 and 25 times stronger E6- and E7-specific CD8(+) T cell responses than those of initial E67 fusion construct. In particular, inclusion of electroporation in intramuscular immunization of tFE67(Co) further enhances HPV-specific CD8(+) T cell responses, leading to complete tumor regression in a therapeutic setting. Thus, our results provide valuable insight on effective HPV DNA vaccine design and suggest that tFE67(Co) delivered with electroporation may be a promising therapeutic HPV DNA vaccine against cervical cancer.
Seo
Sang Hwan
SH
Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, Republic of Korea.
Jin
Hyun Tak
HT
Park
Sang Hoon
SH
Youn
Je In
JI
Sung
Young-Chul
YC
D000818:Animals; D023201:CD40 Ligand / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology*; D002460:Cell Line; D018274:Electroporation; D005260:Female; D052162:Human papillomavirus 16 / Q000235:genetics / Q000276:immunology; D007111:Immunity, Cellular; D008565:Membrane Proteins / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology; D050725:Papillomavirus E7 Proteins; D030361:Papillomavirus Infections / Q000276:immunology / Q000517:prevention & control*; D053918:Papillomavirus Vaccines / Q000235:genetics / Q000276:immunology*; D015202:Protein Engineering; D012097:Repressor Proteins / Q000235:genetics / Q000276:immunology; D002583:Uterine Cervical Neoplasms / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology
D019496:Cancer Vaccines; C068651:E6 protein, Human papillomavirus type 16; D008565:Membrane Proteins; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D053918:Papillomavirus Vaccines; D012097:Repressor Proteins; D019444:Vaccines, DNA; C084881:flt3 ligand protein; C059731:oncogene protein E7, Human papillomavirus type 16; D023201:CD40 Ligand