Human γδ thymocytes are functionally immature and differentiate into cytotoxic type 1 effector T cells upon IL-2/IL-15 signaling

J Immunol. 2014 Mar 1;192(5):2237-43. doi: 10.4049/jimmunol.1303119. Epub 2014 Jan 31.

Abstract

Cytotoxicity and IFN-γ production by human γδ T cells underlie their potent antitumor functions. However, it remains unclear where and how human γδ T cells acquire these key effector properties. Given the recent disclosure of a major contribution of the thymus to murine γδ T cell functional differentiation, in this study we have analyzed a series of human pediatric thymuses. We found that ex vivo-isolated γδ thymocytes produced negligible IFN-γ and lacked cytolytic activity against leukemia cells. However, these properties were selectively acquired upon stimulation with IL-2 or IL-15, but not IL-4 or IL-7. Unexpectedly, TCR activation was dispensable for these stages of functional differentiation. The effects of IL-2/IL-15 depended on MAPK/ERK signaling and induced de novo expression of the transcription factors T-bet and eomesodermin, as well as the cytolytic enzyme perforin, required for the cytotoxic type 1 program. These findings have implications for the manipulation of γδ T cells in cancer immunotherapy.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Differentiation / physiology*
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Immunotherapy
  • Infant
  • Infant, Newborn
  • Interleukin-15 / genetics
  • Interleukin-15 / immunology*
  • Interleukin-15 / metabolism
  • Interleukin-2 / genetics
  • Interleukin-2 / immunology*
  • Interleukin-2 / metabolism
  • MAP Kinase Signaling System / physiology*
  • Male
  • Neoplasms / genetics
  • Neoplasms / immunology
  • Neoplasms / metabolism
  • Neoplasms / therapy
  • Receptors, Antigen, T-Cell, gamma-delta / genetics
  • Receptors, Antigen, T-Cell, gamma-delta / immunology*
  • Receptors, Antigen, T-Cell, gamma-delta / metabolism
  • T-Box Domain Proteins / genetics
  • T-Box Domain Proteins / immunology
  • T-Box Domain Proteins / metabolism
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism

Substances

  • Eomes protein, mouse
  • IL15 protein, human
  • IL2 protein, human
  • Interleukin-15
  • Interleukin-2
  • Receptors, Antigen, T-Cell, gamma-delta
  • T-Box Domain Proteins
  • T-box transcription factor TBX21