Interleukin 9 and its receptor: an overview of structure and function

Int Rev Immunol. 1998;16(3-4):345-64. doi: 10.3109/08830189809043001.


Interleukin-9 (IL-9) is a multifunctional cytokine produced by activated TH2 clones in vitro and during TH2-like T cell responses in vivo. Although IL-9 was initially described as a T cell growth factor, its role in T cell responses is still unclear. While freshly isolated normal T cells do not respond to IL-9, this cytokine induces the proliferation of murine T cell lymphomas in vitro, and in vivo overexpression of IL-9 results in the development of thymic lymphomas. In the human, the existence of an IL-9 mediated autocrine loop has been suggested for some malignancies such as Hodgkin's disease. Various observations indicate that IL-9 is actively involved in mast cells responses by inducing the proliferation and differentiation of these cells. Other potential biological targets for IL-9 include B lymphocytes, and hematopoietic progenitors, for which higher responses were observed with foetal or transformed cells as compared to normal adult progenitors. The IL-9 receptor is a member of the hemopoietin receptor superfamily and interacts with the gamma chain of the IL-2 receptor for signaling. Signal transduction studies have stressed the role of the Jak-STAT pathway in various IL-9 bioactivities, whereas the 4PS/IRS2 adaptor protein might also play a significant role in IL-9 signaling.

Publication types

  • Review

MeSH terms

  • Animals
  • Humans
  • Interleukin-9* / chemistry
  • Interleukin-9* / physiology
  • Mice
  • Molecular Structure
  • Receptors, Interleukin* / chemistry
  • Receptors, Interleukin* / physiology
  • Receptors, Interleukin-9


  • IL9R protein, human
  • Interleukin-9
  • Receptors, Interleukin
  • Receptors, Interleukin-9