title: IL-21 limits peripheral lymphocyte numbers through T cell homeostatic mechanisms.
abstract: BACKGROUND
  IL-21, a member of the common gamma-chain utilizing family of cytokines, participates in immune and inflammatory processes. In addition, the cytokine has been linked to autoimmunity in humans and rodents.
  
  
  RESULTS
  To investigate the mechanism whereby IL-21 affects the immune system, we investigated its role in T cell homeostasis and autoimmunity in both non-autoimmune C57BL/6 and autoimmune NOD mice. Our data indicate that IL-21R knockout C57BL/6 and NOD mice show increased size of their lymphocyte population and decreased homeostatic proliferation. In addition, our experimental results demonstrate that IL-21 inhibits T cell survival. These data suggest that IL-21 acts to limit the size of the T cell pool. Furthermore, our data suggest IL-21 may contribute to the development of autoimmunity.
  
  
  CONCLUSIONS
  Taken together, our results suggest that IL-21 plays a global role in regulating T cell homeostasis, promoting the continuous adaptation of the T cell lymphoid space.
authors.affiliation: Department of Immunology, The Scripps Research Institute, La Jolla, California, United States of America.
authors.forename: Shrimati
authors.initials: S
authors.lastname: Datta
authors.forename: Nora E
authors.initials: NE
authors.lastname: Sarvetnick
mesh_terms: D000818:Animals; D000941:Antigens / Q000737:chemistry; D015551:Autoimmunity; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D006706:Homeostasis; D006801:Humans; D007378:Interleukins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D008954:Models, Biological; D053655:Receptors, Interleukin-21 / Q000235:genetics; D013601:T-Lymphocytes / Q000378:metabolism* / Q000502:physiology*; D000098546:Interleukin-21
chemical_list: D000941:Antigens; D007378:Interleukins; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21
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