IL-7 production in murine lymphatic endothelial cells and induction in the setting of peripheral lymphopenia

Int Immunol. 2013 Aug;25(8):471-83. doi: 10.1093/intimm/dxt012. Epub 2013 May 8.


IL-7 is a required factor for T-cell homeostasis. Because of low expression levels and poor reagent availability, the cellular sources of IL-7 have proven challenging to characterize. In this study, we describe a reporter mouse in which enhanced GFP is expressed from the endogenous Il7 locus. We show that IL-7 is produced by lymphatic endothelial cells (LECs) distributed throughout the systemic lymphatic vasculature as well as by fibroblastic reticular cells, and that phosphorylation of STAT5 in lymphocytes is higher in lymphatics than in blood. Furthermore, in nodes depleted of lymphocytes, Il7 transcription is increased in stromal but not in myeloid subsets. These data support recent findings that lymphocyte homeostasis is influenced by access to secondary lymphoid organs and point to LECs as an important in vivo source of IL-7, bathing trafficking immune cells under both resting and lymphopenic conditions.

Keywords: HIV; endothelium; interleukin-7; lymph node; lymphatic; lymphopenia; myeloid; stromal.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Endothelial Cells / cytology
  • Endothelial Cells / immunology*
  • Endothelial Cells / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / immunology
  • Green Fluorescent Proteins / metabolism
  • Interleukin-7 / biosynthesis*
  • Interleukin-7 / immunology
  • Interleukin-7 / metabolism
  • Lymphatic System / cytology*
  • Lymphopenia / immunology*
  • Lymphopenia / metabolism
  • Mice
  • Mice, Transgenic
  • Phosphorylation
  • STAT5 Transcription Factor / metabolism


  • Interleukin-7
  • STAT5 Transcription Factor
  • Green Fluorescent Proteins