Diversification of T-helper-cell lineages: finding the family root of IL-17-producing cells

Nat Rev Immunol. 2006 Apr;6(4):329-33. doi: 10.1038/nri1807.


CD4+ T helper 1 (T(H)1) and T(H)2 cells have long been regarded as two sides of a coin in terms of adaptive immune responses. However, as I discuss here, this concept needs to be reconsidered. In particular, recent data indicate that interleukin-17 (IL-17) is produced by T(H) cells that are distinct from the traditional T(H)1- and T(H)2-cell subsets. Furthermore, the generation of these IL-17-producing CD4+ T cells from naive precursors during immune responses is not dependent on the cytokines and transcription factors that mediate T(H)1- and T(H)2-cell development. Given that IL-17 has crucial roles in regulating tissue inflammation and the development of disease in several animal models of autoimmunity, I propose that IL-17-producing CD4+ T cells represent a distinct inflammatory T(H)-cell lineage.

Publication types

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

MeSH terms

  • Animals
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • Cell Differentiation / immunology
  • Cell Differentiation / physiology
  • Cell Lineage / immunology*
  • Humans
  • Inflammation / immunology
  • Inflammation / metabolism
  • Interleukin-17 / biosynthesis
  • Interleukin-17 / physiology
  • Interleukin-23
  • Interleukin-23 Subunit p19
  • Interleukins / biosynthesis
  • Interleukins / physiology
  • Models, Immunological
  • T-Lymphocyte Subsets / cytology*
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocyte Subsets / metabolism
  • T-Lymphocytes, Helper-Inducer / cytology*
  • T-Lymphocytes, Helper-Inducer / immunology
  • T-Lymphocytes, Helper-Inducer / metabolism


  • IL23A protein, human
  • Interleukin-17
  • Interleukin-23
  • Interleukin-23 Subunit p19
  • Interleukins