IL-2 family of cytokines in T regulatory cell development and homeostasis.
BACKGROUND
Interleukin 2 (IL-2) induces an essential signal for T regulatory (Treg) cells. Without a functional IL-2R, only immature CD4(+) Foxp3(low) CD25(neg) T cells develop, and these cells fail to suppress autoreactive T cells in the periphery.


CONCLUSIONS
IL-2 functions during Treg cell development by upregulating Foxp3 and CD25 and by increasing the number of thymic Treg cells. Upon exiting the thymus during neonatal life, IL-2 is responsible for rapid amplification of the number of Treg cells in peripheral lymph nodes to insure suppression of autoreactive T cells that escape negative selection, thereby maintaining tolerance. The homeostasis of Treg cells in mature immunocompetent mice also depends on IL-2. However, there is an alternative mechanism for Treg cells homeostasis that may represent a minor IL-2-independent pathway or the consequence of weak and very transient IL-2R signaling.


CONCLUSIONS
Thus, IL-2 provides importance signals for Treg cell development and for their homeostasis in peripheral immune tissues.
Malek
Thomas R
TR
Department of Microbiology and Immunology, University of Miami, RMSB 3119, Miami, FL, USA. tmalek@med.miami.edu
Yu
Aixin
A
Zhu
Linjian
L
Matsutani
Takaji
T
Adeegbe
Dennis
D
Bayer
Allison L
AL
D000818:Animals; D015551:Autoimmunity; D002454:Cell Differentiation / Q000276:immunology; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000378:metabolism*; D006706:Homeostasis / Q000276:immunology; D007108:Immune Tolerance / Q000276:immunology; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000254:growth & development* / Q000276:immunology
D016207:Cytokines; D051858:Forkhead Transcription Factors; D007376:Interleukin-2