Ectopic lymphoid-organ development occurs through interleukin 7-mediated enhanced survival of lymphoid-tissue-inducer cells

Immunity. 2007 May;26(5):643-54. doi: 10.1016/j.immuni.2007.04.009.


Development of Peyer's patches and lymph nodes requires the interaction between CD4+ CD3- IL-7Ralpha+ lymphoid-tissue inducer (LTi) and VCAM-1+ organizer cells. Here we showed that by promoting their survival, enhanced expression of interleukin-7 (IL-7) in transgenic mice resulted in accumulation of LTi cells. With increased IL-7 availability, de novo formation of VCAM-1+ Peyer's patch anlagen occurred along the entire fetal gut resulting in a 5-fold increase in Peyer's patch numbers. IL-7 overexpression also led to formation of multiple organized ectopic lymph nodes and cecal patches. After immunization, ectopic lymph nodes developed normal T cell-dependent B cell responses and germinal centers. Mice overexpressing IL-7 but lacking either RORgamma, a factor required for LTi cell generation, or lymphotoxin alpha1beta2 had neither Peyer's patches nor ectopic lymph nodes. Therefore, by controlling LTi cell numbers, IL-7 can regulate the formation of both normal and ectopic lymphoid organs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / immunology*
  • Cell Survival
  • Cells, Cultured
  • Fetus / metabolism
  • Gene Expression Regulation
  • Interleukin-7 / genetics
  • Interleukin-7 / metabolism*
  • Lymphoid Tissue / cytology*
  • Lymphoid Tissue / immunology
  • Lymphoid Tissue / metabolism*
  • Mice
  • Mice, Transgenic
  • Stem Cells / cytology
  • Stem Cells / metabolism
  • T-Lymphocytes, Helper-Inducer / cytology*
  • T-Lymphocytes, Helper-Inducer / immunology
  • T-Lymphocytes, Helper-Inducer / metabolism*
  • Vascular Cell Adhesion Molecule-1 / metabolism


  • Interleukin-7
  • Vascular Cell Adhesion Molecule-1