Immunologic Research

, Volume 34, Issue 3, pp 229–242

IL-17A-producing neutrophil-regulatory Tn lymphocytes



The proinflammatory cytokine IL-17A, mainly produced by specialized T cells, plays an important homeostatic role in regulating neutrophil production and blood neutrophil counts. This review will assemble and discuss the evidence for this function of IL-17A-producing cells, which are collectively called neutrophil-regulatory T cells or Tn cells. IL-17A-producing lymphocytes are most abundant in the mesenteric lymph node, where they account for 0.15% of all lymphocytes. About 60% of the Tn cells are γδ T cells, about 25% NKT-like cells, and less than 15% are CD4 T cells. These latter cells are also known as T-17 or ThIL-17 cells, a subset of Tn cells that also plays an important role in autoimmune diseases. IL-17A produced by Tn cells regulates the production of G-CSF, which in turn promotes the proliferation of promyelocytes and maturation of neutrophils. This homeostatic mechanism plays an important role in normal physiology and in host defense against bacterial infections. This review is aimed at highlighting the important role of IL-17A-producing T cells at the interface between the adaptive and innate immune system.

Key Words

IL-17 Neutrophil IL-23 Homeostasis Tn cells G-CSF 


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Copyright information

© Humana Press Inc 2006

Authors and Affiliations

  1. 1.Department of Biomedical EngineeringUniversity of VirginiaCharlottesvilleUSA
  2. 2.Department of Molecular Physiology and Biological PhysicsUniversity of VirginiaCharlottesvilleUSA
  3. 3.Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesville

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