title: Interleukin 7 signaling in dendritic cells regulates the homeostatic proliferation and niche size of CD4+ T cells.
abstract: Interleukin 7 (IL-7) and T cell antigen receptor signals have been proposed to be the main drivers of homeostatic T cell proliferation. However, it is not known why CD4(+) T cells undergo less-efficient homeostatic proliferation than CD8(+) T cells do. Here we show that systemic IL-7 concentrations increased during lymphopenia because of diminished use of IL-7 but that IL-7 signaling on IL-7 receptor-alpha-positive (IL-7Ralpha(+)) dendritic cells (DCs) in lymphopenic settings paradoxically diminished the homeostatic proliferation of CD4(+) T cells. This effect was mediated at least in part by IL-7-mediated downregulation of the expression of major histocompatibility complex class II on IL-7Ralpha(+) DCs. Our results indicate that IL-7Ralpha(+) DCs are regulators of the peripheral CD4(+) T cell niche and that IL-7 signals in DCs prevent uncontrolled CD4(+) T cell population expansion in vivo.
authors.affiliation: Pediatric Oncology Branch, National Cancer Institute, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Guimond
authors.forename: Rachelle G
authors.initials: RG
authors.lastname: Veenstra
authors.forename: David J
authors.initials: DJ
authors.lastname: Grindler
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Yongzhi
authors.initials: Y
authors.lastname: Cui
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Murphy
authors.forename: Su Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Risu
authors.initials: R
authors.lastname: Na
authors.forename: Lothar
authors.initials: L
authors.lastname: Hennighausen
authors.forename: Sema
authors.initials: S
authors.lastname: Kurtulus
authors.forename: Batu
authors.initials: B
authors.lastname: Erman
authors.forename: Polly
authors.initials: P
authors.lastname: Matzinger
authors.forename: Melinda S
authors.initials: MS
authors.lastname: Merchant
authors.forename: Crystal L
authors.initials: CL
authors.lastname: Mackall
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D049109:Cell Proliferation; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D025461:Feedback, Physiological; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism; D006706:Homeostasis / Q000276:immunology*; D015851:Interleukin-7 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology; D008231:Lymphopenia / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D020395:Receptors, Interleukin-7 / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D017154:Stromal Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D000949:Histocompatibility Antigens Class II; D015851:Interleukin-7; D020395:Receptors, Interleukin-7