title: Expression and function of TNF and IL-1 receptors on human regulatory T cells.
abstract: Regulatory T cells (Tregs) suppress immune activation and are critical in preventing autoimmune diseases. While the ability of Tregs to inhibit proliferation of other T cells is well established, it is not yet clear whether Tregs also modulate inflammatory cytokines during an immune response. Here, we show that the expression of inflammatory cytokine receptors IL-1R1 and TNFR2 were higher on resting mature Tregs compared to naïve or memory T cells. While upon activation through the T cell receptor (TCR), expression of IL-1R1 and TNFR2 were upregulated on all T cell subsets, IL-1R1 maintained significantly higher expression on activated Tregs as compared to other T cell subsets. The decoy receptor for IL-1 (IL-1R2) was not expressed by any of the resting T cells but was rapidly upregulated and preferentially expressed upon TCR-stimulation on Tregs. In addition, we found that Tregs also expressed high levels of mRNA for IL-1 antagonist, IL-1RA. TCR-stimulation of naïve T cells in the presence of TGFbeta, which induces FOXP3 expression, however did not result in upregulation of IL-1R1 or IL-1R2. In addition, ectopic expression of FOXP3 in non-Tregs, while causing significant upregulation of IL-1R1 and IL-1R2, did not achieve the levels seen in bona fide Tregs. We also determined that resting human Tregs expressing IL-1R1 did not have higher suppressive capacity compared to IL-1R1- Tregs, suggesting that IL-1R1 does not discriminate suppressive resting Tregs in healthy individuals. Functionally, activated human Tregs displayed a capacity to neutralize IL-1beta, which suggests a physiological significance for the expression of IL-1 decoy receptor on Tregs. In conclusion, our findings that human Tregs preferentially express receptors for TNF and IL-1 suggest a potential function in sensing and dampening local inflammation.
authors.affiliation: Department of Microbiology, New York University School of Medicine, New York, New York, United States of America.
authors.forename: Frances
authors.initials: F
authors.lastname: Mercer
authors.forename: Lina
authors.initials: L
authors.lastname: Kozhaya
authors.forename: Derya
authors.initials: D
authors.lastname: Unutmaz
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D006801:Humans; D009500:Neutralization Tests; D012333:RNA, Messenger / Q000235:genetics; D017472:Receptors, Interleukin-1 / Q000235:genetics / Q000502:physiology*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000235:genetics / Q000502:physiology*; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D047889:Receptors, Tumor Necrosis Factor, Type II