Interleukin 4: signalling mechanisms and control of T cell differentiation

Ciba Found Symp. 1997:204:208-16; discussion 216-9. doi: 10.1002/9780470515280.ch14.

Abstract

Interleukin 4 (IL-4) is a pleiotropic type I cytokine that controls both growth and differentiation among haemopoietic and non-haemopoietic cells. Its receptor is a heterodimer. One chain, the IL-4R alpha chain, binds IL-4 with high affinity and determines the nature of the biochemical signals that are induced. The second chain, gamma c, is required for the induction of such signals. IL-4-mediated growth depends upon activation events that involve phosphorylation of Y497 of IL-4R alpha, leading to the binding and phosphorylation of 4PS/IRS-2 in haemopoietic cells and of IRS-1 in non-haemopoietic cells. By contrast, IL-4-mediated differentiation events depend upon more distal regions of the IL-4R alpha chain that include a series of STAT-6 binding sites. The distinctive roles of these receptor domains was verified by receptor-reconstruction experiments. The 'growth' and 'differentiation' domains of the IL-4R alpha chain, independently expressed as chimeric structures with a truncated version of the IL-2R beta chain, were shown to convey their functions to the hybrid receptor. The critical role of STAT-6 in IL-4-mediated gene activation and differentiation was made clear by the finding that lymphocytes from STAT-6 knockout mice are strikingly deficient in these functions but have retained the capacity to grow, at least partially, in response to IL-4. IL-4 plays a central role in determining the phenotype of naive CD4+ T cells. In the presence of IL-4, newly primed naive T cells develop into IL-4 producers while in its absence they preferentially become gamma-interferon (IFN-gamma) producers. Recently, a specialized subpopulation of T cells, CD4+/NK1.1+ cells, has been shown to produce large amounts of IL-4 upon stimulation. Two examples of mice with deficiencies in these cells are described--beta 2-microglobulin knockout mice and SJL mice. Both show defects in the development of IL-4-producing cells and in the increase in serum IgE in response to stimulation with the polyclonal stimulant anti-IgD. Both sets of mice have major diminutions in the number of CD4+/ NK1.1+ T cells, strongly indicating an important role of these cells in some but not all IgE responses to physiologic stimuli.

Publication types

  • Review

MeSH terms

  • Animals
  • Antigens, CD / physiology*
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / immunology
  • Cell Differentiation
  • Cell Division
  • Cytokines / physiology
  • Interleukin-4 / physiology*
  • Killer Cells, Natural / immunology
  • Lymphocyte Activation
  • Mice
  • Mice, Knockout
  • Mice, Mutant Strains
  • Receptors, Interleukin / physiology*
  • Receptors, Interleukin-2 / physiology
  • Receptors, Interleukin-4
  • STAT6 Transcription Factor
  • T-Lymphocytes / cytology*
  • T-Lymphocytes / immunology
  • Th2 Cells / immunology
  • Trans-Activators / physiology

Substances

  • Antigens, CD
  • Cytokines
  • Receptors, Interleukin
  • Receptors, Interleukin-2
  • Receptors, Interleukin-4
  • STAT6 Transcription Factor
  • Stat6 protein, mouse
  • Trans-Activators
  • Interleukin-4