Targeting human papillomavirus type 16 E7 to the endosomal/lysosomal compartment enhances the antitumor immunity of DNA vaccines against murine human papillomavirus type 16 E7-expressing tumors

Hum Gene Ther. 1999 Nov 20;10(17):2727-40. doi: 10.1089/10430349950016474.


DNA vaccination is an attractive approach for tumor immunotherapy because of its stability and simplicity of delivery. Advances demonstrate that helper T cell responses play a critical role in initiating immune responses. The aim of the current study is to test whether targeting HPV-16 E7 to the endosomal/lysosomal compartment can enhance the potency of DNA vaccines. We linked the lysosome-associated membrane protein 1 (LAMP-1) to HPV-E7 to construct a chimeric DNA, Sig/E7/LAMP-1 DNA. For in vivo tumor prevention experiments, mice were vaccinated with E7 DNA or Sig/E7/LAMP-1 DNA via gene gun, followed by tumor challenge. For in vivo tumor regression experiments, mice were first challenged with tumor cells and then vaccinated with E7-DNA or Sig/E7/LAMP-1 DNA. Intracellular cytokine staining with flow cytometry analysis, cytotoxic T lymphocyte (CTL) assays, enzyme-linked immunoabsorbent assay (ELISA), and enzyme-linked immunospot (ELISPOT) assays were used for in vitro E7-specific immunological studies. In both tumor prevention and tumor regression assays, Sig/E7/LAMP-1 DNA generated greater antitumor immunity than did wild-type E7 DNA. In addition, mice vaccinated with Sig/E7/LAMP-1 DNA had greater numbers of E7-specific CD4+ helper T cells, higher E7-specific CTL activity, and greater numbers of CD8+ T cell precursors than did mice vaccinated with Sig/E7 or wild-type E7 DNA. Sig/E7 generated a stronger E7-specific antibody response than did Sig/E7/LAMP-1 or wild-type E7 DNA. Our results indicate that linkage of the antigen gene to an endosomal/lysosomal targeting signal may greatly enhance the potency of DNA vaccines.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Dendritic Cells / immunology
  • Endosomes / immunology
  • Histocompatibility Antigens Class I / immunology
  • Lysosome-Associated Membrane Glycoproteins
  • Lysosomes / immunology
  • Membrane Glycoproteins / genetics
  • Mice
  • Mice, Inbred C57BL
  • Neoplasms, Experimental / genetics
  • Neoplasms, Experimental / immunology
  • Neoplasms, Experimental / therapy*
  • Neoplasms, Experimental / virology
  • Oncogene Proteins, Viral / genetics*
  • Oncogene Proteins, Viral / immunology
  • Papillomavirus E7 Proteins
  • Protein Sorting Signals / genetics
  • Vaccines, DNA / genetics
  • Vaccines, DNA / immunology
  • Vaccines, DNA / therapeutic use*


  • Antigens, CD
  • Histocompatibility Antigens Class I
  • Lysosome-Associated Membrane Glycoproteins
  • Membrane Glycoproteins
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • Protein Sorting Signals
  • Vaccines, DNA
  • oncogene protein E7, Human papillomavirus type 16