Enhanced in vivo gene expression mediated by listeriolysin O incorporated anionic LPDII: Its utility in cytotoxic T lymphocyte-inducing DNA vaccine

J Control Release. 2010 Dec 1;148(2):219-25. doi: 10.1016/j.jconrel.2010.06.017. Epub 2010 Jul 7.


Enhanced in vivo gene expression using non-viral vectors is a critical issue in gene therapy in general. Among the many potential utilities of non-viral vector-mediated gene delivery, its application in DNA-based vaccination is an attractive approach with several practical advantages over conventional vaccination. We have previously shown that the endosomolytic bacterial protein listeriolysin O (LLO) is capable of facilitating transfection in vitro using the LPDII (anionic liposome-polycation-DNA complexes) delivery system. In the present study we have extended and investigated the DNA delivery of LLO-containing LPDII to in vivo and evaluated its utility in DNA vaccination in mice. We further investigated the ability of this non-viral gene delivery system to elicit an immune response to a model antigen ovalbumin (OVA), particularly focusing on the OVA-specific CD8(+) cytotoxic T lymphocyte (CTL) response, after delivery of a plasmid containing the OVA cDNA. A DNA prime and protein boost protocol was employed to generate cytotoxic T cell responses. Our results show that increased in vitro and in vivo transfection efficiencies were observed when LLO was incorporated into LPDII. This LLO-LPDII formulation produced an enhanced functional antigen-specific CD8(+) T cell response in vivo compared to the heat-inactivated LLO-containing LPDII (HI-LLO-LPDII) formulation. Furthermore, a significantly higher CTL frequency was observed in the splenocytes isolated from the mice primed with LLO-LPDII by an enzyme-linked immunosorbent spot assay. Interferon-γ production upon specific stimulation by OVA-specific CD8(+) peptide was also significantly stronger with the inclusion of LLO into LPDII. These findings suggest that the LLO-containing LPDII system possesses noteworthy potential as a candidate carrier for DNA vaccine delivery.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Bacterial Toxins / metabolism*
  • Cell Line
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Gene Expression Regulation
  • Heat-Shock Proteins / metabolism*
  • Hemolysin Proteins / metabolism*
  • Immunization
  • Injections, Intravenous
  • Interferon-gamma / metabolism
  • Liposomes
  • Mice
  • Mice, Inbred C57BL
  • Ovalbumin / administration & dosage
  • Ovalbumin / genetics
  • Ovalbumin / immunology*
  • Ovalbumin / metabolism
  • Polyamines
  • Polyelectrolytes
  • Recombinant Proteins / metabolism
  • T-Lymphocytes, Cytotoxic / immunology*
  • Transfection / methods*
  • Vaccines, DNA / administration & dosage
  • Vaccines, DNA / genetics
  • Vaccines, DNA / immunology*
  • Vaccines, DNA / metabolism


  • Bacterial Toxins
  • Heat-Shock Proteins
  • Hemolysin Proteins
  • Liposomes
  • Polyamines
  • Polyelectrolytes
  • Recombinant Proteins
  • Vaccines, DNA
  • polycations
  • Interferon-gamma
  • Ovalbumin
  • hlyA protein, Listeria monocytogenes