IL-33 markedly activates murine eosinophils by an NF-κB-dependent mechanism differentially dependent upon an IL-4-driven autoinflammatory loop

J Immunol. 2013 Oct 15;191(8):4317-25. doi: 10.4049/jimmunol.1301465. Epub 2013 Sep 16.


Eosinophils are major effector cells in type 2 inflammatory responses and become activated in response to IL-4 and IL-33, yet the molecular mechanisms and cooperative interaction between these cytokines remain unclear. Our objective was to investigate the molecular mechanism and cooperation of IL-4 and IL-33 in eosinophil activation. Eosinophils derived from bone marrow or isolated from Il5-transgenic mice were activated in the presence of IL-4 or IL-33 for 1 or 4 h, and the transcriptome was analyzed by RNA sequencing. The candidate genes were validated by quantitative PCR and ELISA. We demonstrated that murine-cultured eosinophils respond to IL-4 and IL-33 by phosphorylation of STAT-6 and NF-κB, respectively. RNA sequence analysis of murine-cultured eosinophils indicated that IL-33 induced 519 genes, whereas IL-4 induced only 28 genes, including 19 IL-33-regulated genes. Interestingly, IL-33 induced eosinophil activation via two distinct mechanisms, IL-4 independent and IL-4 secretion/autostimulation dependent. Anti-IL-4 or anti-IL-4Rα Ab-treated cultured and mature eosinophils, as well as Il4- or Stat6-deficient cultured eosinophils, had attenuated protein secretion of a subset of IL-33-induced genes, including Retnla and Ccl17. Additionally, IL-33 induced the rapid release of preformed IL-4 protein from eosinophils by a NF-κB-dependent mechanism. However, the induction of most IL-33-regulated transcripts (e.g., Il6 and Il13) was IL-4 independent and blocked by NF-κB inhibition. In conclusion, we have identified a novel activation pathway in murine eosinophils that is induced by IL-33 and differentially dependent upon an IL-4 auto-amplification loop.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / immunology
  • Base Sequence
  • Bone Marrow Cells / immunology*
  • Cells, Cultured
  • Eosinophils / immunology*
  • Inflammation / immunology
  • Interleukin-33
  • Interleukin-4 / genetics
  • Interleukin-4 / immunology*
  • Interleukin-4 / metabolism
  • Interleukins / immunology*
  • Interleukins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Mice, Knockout
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism
  • Phosphorylation
  • Receptors, Interleukin-4 / immunology
  • STAT6 Transcription Factor / genetics
  • STAT6 Transcription Factor / metabolism
  • Sequence Analysis, RNA
  • Signal Transduction / immunology


  • Antibodies
  • Il33 protein, mouse
  • Interleukin-33
  • Interleukins
  • NF-kappa B
  • Receptors, Interleukin-4
  • STAT6 Transcription Factor
  • Stat6 protein, mouse
  • Interleukin-4