Contribution of CD8+ T cells to innate immunity: IFN-gamma secretion induced by IL-12 and IL-18

Eur J Immunol. 2002 Oct;32(10):2807-16. doi: 10.1002/1521-4141(2002010)32:10<2807::AID-IMMU2807>3.0.CO;2-0.


The role of CD8+ T cells in adaptive immunity is well documented and involves numerous effector mechanisms including direct cytolysis of targets and secretion of cytokines. The role of CD8+ T cells in innate immunity has not been previously appreciated. Using J774 macrophages infected in vitro with the intracellular bacterium, Listeria monocytogenes (LM), we show that CD8+ T cells isolated from naïve C57BL/6 (B6) mice respond rapidly by secreting IFN-gamma. CD8+ T cells secreting IFN-gamma can also be found in naïve B6 mice 16 h after infection with LM. This rapid IFN-gamma response is TCR-independent and mediated through the actions of IL-12 and IL-18. Cell surface staining and cell sorting experiments indicate that these novel CD8+ T cells express memory markers. In vitro CFSE-labeling experiments show that IFN-gamma-secreting CD8+ T cells proliferate rapidly after 2 days in culture and after 4 days constitute the majority of the CD8+ T cell population. Together, these data suggest an important role for IFN-gamma-secreting CD8+ T cells in the innate response to bacterial pathogens.

Publication types

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

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Line
  • Immunity, Innate*
  • Immunophenotyping
  • Interferon-gamma / biosynthesis*
  • Interleukin-12 / physiology*
  • Interleukin-18 / physiology*
  • Listeria monocytogenes / immunology
  • Mice


  • Interleukin-18
  • Interleukin-12
  • Interferon-gamma