TCR-dependent and -independent activation underlie liver-specific regulation of NKT cells

J Immunol. 2011 Jan 15;186(2):838-47. doi: 10.4049/jimmunol.1001735. Epub 2010 Dec 10.

Abstract

The fate of invariant NKT (iNKT) cells following activation remains controversial and unclear. We systemically examined how iNKT cells are regulated following TCR-dependent and -independent activation with α-galactosylceramide (αGC) or IL-18 plus IL-12, respectively. Our studies reveal activation by αGC or IL-18 plus IL-12 induced transient depletion of iNKT cells exclusively in the liver that was independent of caspase 3-mediated apoptosis. The loss of iNKT cells was followed by repopulation and expansion of phenotypically distinct cells via different mechanisms. Liver iNKT cell expansion following αGC, but not IL-18 plus IL-12, treatment required an intact spleen and IFN-γ. Additionally, IL-18 plus IL-12 induced a more prolonged expansion of liver iNKT cells compared with αGC. iNKT cells that repopulate the liver following αGC had higher levels of suppressive receptors PD-1 and Lag3, whereas those that repopulate the liver following IL-18 plus IL-12 had increased levels of TCR and ICOS. In contrast to acute treatment that caused a transient loss of iNKT cells, chronic αGC or IL-18 plus IL-12 treatment caused long-term systemic loss requiring an intact thymus for repopulation of the liver. This report reveals a previously undefined role for the liver in the depletion of activated iNKT cells. Additionally, TCR-dependent and -independent activation differentially regulate iNKT cell distribution and phenotype. These results provide new insights for understanding how iNKT cells are systemically regulated following activation.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Caspase 3 / metabolism
  • Cell Differentiation / immunology*
  • Galactosylceramides / physiology
  • Immunophenotyping
  • Interleukin-12 / physiology
  • Interleukin-18 / physiology
  • Liver / cytology
  • Liver / immunology*
  • Liver / metabolism*
  • Lymphocyte Activation / immunology*
  • Lymphocyte Depletion* / methods
  • Lymphoid Tissue / cytology
  • Lymphoid Tissue / immunology
  • Lymphoid Tissue / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Natural Killer T-Cells / cytology*
  • Natural Killer T-Cells / immunology*
  • Natural Killer T-Cells / metabolism
  • Receptors, Antigen, T-Cell / metabolism
  • Receptors, Antigen, T-Cell / physiology*
  • Signal Transduction / immunology
  • Spleen / cytology
  • Spleen / immunology
  • Spleen / metabolism

Substances

  • Galactosylceramides
  • Interleukin-18
  • Receptors, Antigen, T-Cell
  • alpha-galactosylceramide
  • Interleukin-12
  • Casp3 protein, mouse
  • Caspase 3