title: Interleukin-21: a critical regulator of the balance between effector and regulatory T-cell responses.
abstract: Naïve T cells can commit to effector [T helper 1 (Th1), Th2 and Th17] or regulatory lineages. Skewing of responses toward inflammatory Th1, Th2 or Th17 pathways and away from regulatory T-cell pathways might be responsible for the initiation and progress of immune-mediated diseases. Based on recent data, we propose that interleukin-21 (IL-21), a cytokine produced by activated CD4+ T cells, induces the development of Th17 cells, blocks the differentiation of transforming growth factor-beta1-induced regulatory T cells and renders CD4+ T cells resistant to the suppressive effects of regulatory T cells, thereby playing a major role in pathogenic T-cell responses.
authors.affiliation: Dipartimento di Medicina Interna e Centro di Eccellenza per lo Studio Delle Malattie Complesse e Multifattoriali, Università Tor Vergata, Rome 00133, Italy. Gi.Monteleone@Med.uniroma2.it <Gi.Monteleone@Med.uniroma2.it>
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monteleone
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallone
authors.forename: Thomas T
authors.initials: TT
authors.lastname: MacDonald
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D007154:Immune System Diseases / Q000628:therapy; D007249:Inflammation; D007378:Interleukins / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000037:antagonists & inhibitors*; D000098546:Interleukin-21
chemical_list: D007378:Interleukins; D053773:Transforming Growth Factor beta1; D000098546:Interleukin-21