Tumor necrosis factor-α causes release of cytosolic interleukin-18 from human neutrophils

Christopher C. Silliman, Marguerite R. Kelher, Fabia Gamboni-Robertson, Christine Hamiel, Kelly M. England, Charles A. Dinarello, Travis H. Wyman, Samina Y. Khan, N. J D McLaughlin, Rachel S. Bercovitz, Anirban Banerjee

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Neutrophils (PMNs) are a vital part of host defense and are the principal leukocyte in innate immunity. Interleukin (IL)-18 is a proinflammatory cytokine with roles in both innate and adaptive immunity. We hypothesize that PMNs contain preformed IL-18, which is released in response to specific inflammatory stimuli. Isolated PMNs were stimulated with a battery of chemoattractants (5 min to 24 h), and IL-18 release was measured. PMNs were also separated into subcellular fractions and immunoblotted with antibodies against IL-18 or were fixed and probed with antibodies to IL-18 as well as to the contents of granules, intracellular organelles, and filamentous actin (F-actin), incubated with fluorescent secondary antibodies, and examined by digital microscopy. Quiescent PMNs contained IL-18 in the cytoplasm, associated with F-actin, as determined by positive fluorescence resonance energy transfer (FRET+). In turn, TNF-α stimulation disrupted the association of IL-18 with F-actin, induced a FRET+ interaction of IL-18 with lipid rafts, and elicited IL-18 release. Manipulation of F-actin status confirmed the relationship between IL-18 and F-actin in resting PMNs. Consequently, incubation with monomeric IL-18 binding protein inhibited TNF-α-mediated priming of the PMN oxidase. We conclude that human PMNs contain IL-18 associated with F-actin in the cytoplasm and TNF-α stimulation causes dissociation of IL-18 from F-actin, association with lipid rafts, and extracellular release. Extracellular IL-18 participates in TNF-α priming of the PMN oxidase as demonstrated by inhibition with the IL-18 binding protein.

Original languageEnglish (US)
Pages (from-to)C714-C724
JournalAmerican Journal of Physiology - Cell Physiology
Issue number3
StatePublished - Mar 2010


  • F-actin
  • Fluorescent resonance energy transfer
  • Lipid rafts

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


Dive into the research topics of 'Tumor necrosis factor-α causes release of cytosolic interleukin-18 from human neutrophils'. Together they form a unique fingerprint.

Cite this