title: SOCS-1 regulates IL-15-driven homeostatic proliferation of antigen-naive CD8 T cells, limiting their autoimmune potential.
abstract: Mice that are deficient in suppressor of cytokine signaling-1 (SOCS-1) succumb to neonatal mortality that is associated with extensive cellular infiltration of many tissues. T cells seem to be necessary for disease, which can be alleviated largely by neutralizing interferon-gamma. Examining T cell receptor (TCR) specificity shows that even monospecific T cells can mediate disease in SOCS-1-deficient mice, although disease onset is substantially faster with a polyclonal T cell repertoire. A major phenotype of SOCS-1-/- mice is the accumulation of CD44(high)CD8+ peripheral T cells. We show that SOCS-1-deficient CD8, but not CD4, T cells proliferate when transferred into normal (T cell-sufficient) mice, and that this is dependent on two signals: interleukin (IL)-15 and self-ligands that are usually only capable of stimulating homeostatic expansion in T cell-deficient mice. Our findings reveal that SOCS-1 normally down-regulates the capacity of IL-15 to drive activation and proliferation of naive CD8 T cells receiving TCR survival signals from self-ligands. We show that such dysregulated proliferation impairs the deletion of a highly autoreactive subset of CD8 T cells, and increases their potential for autoimmunity. Therefore, impaired deletion of highly autoreactive CD8 T cells, together with uncontrolled activation of naive CD8 T cells by homeostatic survival ligands, may provide a basis for the T cell-mediated disease of SOCS-1-/- mice.
authors.affiliation: The Walter and Eliza Hall Institute of Medical Research, Parkville, 3050 Victoria, Australia.
authors.forename: Gayle M
authors.initials: GM
authors.lastname: Davey
authors.forename: Robyn
authors.initials: R
authors.lastname: Starr
authors.forename: Ann L
authors.initials: AL
authors.lastname: Cornish
authors.forename: J Theodore
authors.initials: JT
authors.lastname: Burghardt
authors.forename: Warren S
authors.initials: WS
authors.lastname: Alexander
authors.forename: Francis R
authors.initials: FR
authors.lastname: Carbone
authors.forename: Charles D
authors.initials: CD
authors.lastname: Surh
authors.forename: William R
authors.initials: WR
authors.lastname: Heath
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015551:Autoimmunity / Q000276:immunology*; D016026:Bone Marrow Transplantation; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D049109:Cell Proliferation; D005434:Flow Cytometry; D007108:Immune Tolerance / Q000276:immunology; D019409:Interleukin-15 / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D012097:Repressor Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology*; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D018183:Transplantation Chimera
chemical_list: D002352:Carrier Proteins; D019409:Interleukin-15; D012097:Repressor Proteins; C491590:Socs1 protein, mouse; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins