Successful immunogene therapy using colon cancer cells (colon 26) transfected with plasmid vector containing mature interleukin-18 cDNA and the Igkappa leader sequence

Cancer Gene Ther. 2001 Jan;8(1):9-16. doi: 10.1038/sj.cgt.7700277.


IL-18 is a novel cytokine that induces interferon (IFN)-gamma secretion and plays an important role in antitumor immunity. In the present study, we constructed plasmid vectors encoding the murine mature IL-18 cDNA linked with the Igkappa leader sequence and the pro-IL-18 cDNA to estimate the efficacy of the mature IL- 18 vector and to evaluate IL-18--producing tumor cells as a tumor vaccine. Colon 26 cells were transfected with the abovementioned vectors or with vector alone (mock). Reverse transcription-polymerase chain reaction analysis showed increased expression of murine IL-18 cDNA in both mature IL-18 and pro-IL-18 transfectants in comparison to that in mock transfected cells. The ability of the culture supernatants of mature IL-18 transfectants to induce IFN-gamma secretion was extremely high (40-140 pg/10(6) cells) in comparison to that of pro-IL-18 transfectants (4-18 pg/10(6) cells). When injected into syngeneic BALB/c mice, the growth of mature IL-18 transfectants, but not pro-IL-18 transfectants, was significantly less than that in mock transfected cells ( P< .01, by ANOVA and analysis of covariance). In addition, injection of colon 26 or Meth-A cells into mice immunized with a mature IL-18 transfectant revealed acquired immunity. Depletion of natural killer cells did not affect the growth of transfectants. However, the growth inhibitory effects were partially abrogated following treatment with anti-CD4+ and anti-CD8+ antibodies. These data suggest that the rejection of mature IL-18/colon 26 cells was mediated through T-cell activation. Gene therapy using mature IL-18 transfectants containing a plasmid vector and the Igkappa leader sequence may be a useful tumor vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Antigens, CD / metabolism
  • B7-1 Antigen / metabolism
  • B7-2 Antigen
  • CD4 Antigens / metabolism
  • CD8 Antigens / metabolism
  • Colonic Neoplasms / therapy*
  • DNA Primers / chemistry
  • Fibrosarcoma / chemically induced
  • Fibrosarcoma / therapy*
  • Gene Expression
  • Genes, MHC Class I / physiology
  • Genes, MHC Class II / physiology
  • Genetic Therapy / methods*
  • Genetic Vectors* / administration & dosage
  • Genetic Vectors* / genetics
  • Immunoenzyme Techniques
  • Immunoglobulin G / immunology
  • Immunoglobulins / genetics*
  • Immunoglobulins / metabolism
  • Interferon-gamma / metabolism
  • Interleukin-18 / genetics*
  • Interleukin-18 / metabolism
  • Killer Cells, Natural / metabolism
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Neoplasm Transplantation
  • Recombinant Fusion Proteins / administration & dosage
  • Recombinant Fusion Proteins / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transfection / methods
  • Tumor Cells, Cultured


  • Antigens, CD
  • B7-1 Antigen
  • B7-2 Antigen
  • CD4 Antigens
  • CD8 Antigens
  • Cd86 protein, mouse
  • DNA Primers
  • IgK
  • Immunoglobulin G
  • Immunoglobulins
  • Interleukin-18
  • Membrane Glycoproteins
  • Recombinant Fusion Proteins
  • Interferon-gamma