Helios: still behind the clouds

Immunology. 2019 Nov;158(3):161-170. doi: 10.1111/imm.13115. Epub 2019 Oct 13.

Abstract

Regulatory T (Treg) cells are a subset of CD4+ T cells that are critical for the maintenance of self-tolerance. The forkhead box transcription factor Foxp3 is a master regulator for the Treg phenotype and function and its expression is essential in Treg cells, as the loss of Foxp3 results in lethal autoimmunity. Two major subsets of Treg cells have been described in vivo; thymus-derived Treg (tTreg) cells that develop in the thymus and peripherally induced Treg (pTreg) cells that are derived from conventional CD4+ Foxp3- T cells and are converted in peripheral tissues to cells that express Foxp3 and acquire suppressive ability. The transcription factor Helios, a member of the Ikaros transcription factor family, is expressed in 60-70% of Treg cells in both mouse and man, and is believed to be a marker of tTreg cells. In this review, we discuss the role and function of Helios in Treg cells, the controversy surrounding the use of Helios as a marker of tTreg cells, and how Helios controls specific aspects of the Treg cell program.

Keywords: autoimmunity; regulation/suppression; regulatory T cells; transcription factors.

Publication types

  • Research Support, N.I.H., Intramural
  • Review

MeSH terms

  • Animals
  • Antigens, Differentiation / immunology*
  • DNA-Binding Proteins / immunology*
  • Forkhead Transcription Factors / immunology*
  • Humans
  • Ikaros Transcription Factor / immunology*
  • Mice
  • T-Lymphocytes, Regulatory / immunology*
  • Transcription Factors / immunology*

Substances

  • Antigens, Differentiation
  • DNA-Binding Proteins
  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • Foxp3 protein, mouse
  • IKZF2 protein, human
  • Transcription Factors
  • Zfpn1a2 protein, mouse
  • Ikaros Transcription Factor