IFN-γ-independent synergistic effects of IL-12 and IL-15 induce anti-tumor immune responses in syngeneic mice

Alberto Comes, Emma Di Carlo, Piero Musiani, Ombretta Rosso, Raffaella Meazza, Claudia Chiodoni, Mario P. Colombo, Silvano Ferrini

Research output: Contribution to journalArticlepeer-review

Abstract

IL-15 and IL-12 display anti-tumor activity in different models and IFN-γ has been reported as a secondary mediator of both IL-12 and IL-15 effects. TS/A murine adenocarcinoma cells were engineered to secrete IL-12, IL-15 or both cytokines. TS/A cells secreting IL-15 (TS/A-IL-15) displayed a reduced tumorigenicity (50%) when implanted subcutaneously in syngeneic mice, while both TS/A-IL-12 and TS/A-IL-12/IL-15 were rejected by 100% of animals. In contrast, TS/A-IL-15 and TS/A-IL-12 were tumorigenic in syngeneic IFN-γ knockout mice (100% and >90% of take rate, respectively), but TS/A-IL-12/IL-15 were completely rejected by 90% of these mice. All IFN-γ-deficient mice rejecting TS/A-IL-12/IL-15 developed protective immunity against wild-type TS/A, as indicated by re-challenge experiments. Immunohistochemical analysis of the TS/A-IL-12/IL-15 tumor rejection area in IFN-γ-deficient mice showed a marked reactive cell infiltration constituted of CD8+ cells, granulocytes, NK cells, macrophages and dendritic cells associated with the expression of IL-1β, TNF-α, GM-CSF, MCP-1 and MIP-2. In vivo depletion experiments showed that rejection of TS/A-IL-12/IL-15 cells required CD8+ T lymphocytes and also involved granulocytes, while CD4+ and NK cells played a minor role. These data show IFN-γ-independent synergistic anti-tumor effects of IL-12 and IL-15, involving CD8+ cells and secondary chemokines and cytokines, such as TNF-α.

Original languageEnglish
Pages (from-to)1914-1923
Number of pages10
JournalEuropean Journal of Immunology
Volume32
Issue number7
DOIs
Publication statusPublished - 2002

Keywords

  • Gene transfer
  • IFN-γ knockout
  • IL-12
  • IL-15
  • Tumor immunity

ASJC Scopus subject areas

  • Immunology

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