Commensal microflora and interferon-gamma promote steady-state interleukin-7 production in vivo


  • S. Shalapour
  • K. Deiser
  • O. Sercan
  • J. Tuckermann
  • K. Minnich
  • G. Willimsky
  • T. Blankenstein
  • G.J. Haemmerling
  • B. Arnold
  • T. Schueler


  • European Journal of Immunology


  • Eur J Immunol 40 (9): 2391-2400


  • IL-7 is a major regulator of lymphocyte homeostasis; however, little is known about the mechanisms that regulate IL-7 production. To study Il7 gene regulation in vivo, we generated a novel IL-7-reporter mouse, which allows the non-invasive quantification of Il7 gene activity in live mice and, additionally, the simultaneous activation/inactivation of target genes in IL-7-producing cells. With these IL-7-reporter mice, we identify thymus, skin and intestine as major sources of IL-7 in vivo. Importantly, we show that IFN-gamma and the commensal microflora promote steady-state IL-7 production in the intestine. Furthermore, we demonstrate that the blockade of IFN-gamma signaling in intestinal epithelial cells strongly reduces their IFN-gamma-driven IL-7 production. In summary, our data suggest a feedback loop in which commensal bacteria drive IFN-gamma production by lymphocytes, which in turn promotes epithelial cell IL-7 production and the survival of IL-7-dependent lymphocytes.