A function for IL-7R for CD4+CD25+Foxp3+ T regulatory cells.
The IL-2/IL-2R interaction is important for development and peripheral homeostasis of T regulatory (Treg) cells. IL-2- and IL-2R-deficient mice are not completely devoid of Foxp3+ cells, but rather lack population of mature CD4+CD25+Foxp3high Treg cells and contain few immature CD4+CD25-Foxp3low T cells. Interestingly, common gamma chain (gammac) knockout mice have been shown to have a near complete absence of Foxp3+ Treg cells, including the immature CD25-Foxp3low subset. Therefore, other gammac-cytokine(s) must be critically important during thymic development of CD4+CD25+Foxp3+ Treg cells apart from the IL-2. The present study was undertaken to determine whether the gammac-cytokines IL-7 or IL-15 normally contribute to expression of Foxp3 and Treg cell production. These studies revealed that mice double deficient in IL-2Rbeta and IL-7Ralpha contained a striking lack in the CD4+Foxp3+ population and the Treg cell defect recapitulated the gammac knockout mice. In the absence of IL-7R signaling, IL-15/IL-15R interaction is dispensable for the production of CD4+CD25+Foxp3+ Treg cells, indicating that normal thymic Treg cell production likely depends on signaling through both IL-2 and IL-7 receptors. Selective thymic reconstitution of IL-2Rbeta in mice double deficient in IL-2Rbeta and IL-7Ralpha established that IL-2Rbeta is dominant and sufficient to restore production of Treg cells. Furthermore, the survival of peripheral CD4+Foxp3low cells in IL-2Rbeta-/- mice appears to depend upon IL-7R signaling. Collectively, these data indicate that IL-7R signaling contributes to Treg cell development and peripheral homeostasis.
Department of Microbiology and Immunology, Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA. abayer@med.miami.edu
Allison L
AL
Bayer
Joon Youb
JY
Lee
Anabel
A
de la Barrera
Charles D
CD
Surh
Thomas R
TR
Malek
D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005786:Gene Expression Regulation; D006706:Homeostasis / Q000276:immunology; D007376:Interleukin-2 / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D015851:Interleukin-7 / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D015375:Receptors, Interleukin-2 / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D020395:Receptors, Interleukin-7 / Q000172:deficiency / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D013950:Thymus Gland / Q000378:metabolism
D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D015851:Interleukin-7; D015375:Receptors, Interleukin-2; D020395:Receptors, Interleukin-7