title: Differential roles of IL-2-inducible T cell kinase-mediated TCR signals in tissue-specific localization and maintenance of skin intraepithelial T cells.
abstract: Tissue-specific innate-like gammadelta T cells are important components of the immune system critical for the first line of defense, but mechanisms underlying their tissue-specific development are poorly understood. Our study with prototypical skin-specific intraepithelial gammadeltaT lymphocytes (sIELs) found that among different thymic gammadelta T cell subsets fetal thymic precursors of sIELs specifically acquire a unique skin-homing property after positive selection, suggesting an important role of the TCR selection signaling in "programming" them for tissue-specific development. In this study, we identified IL-2-inducible T cell kinase (ITK) as a critical signal molecule regulating the acquirement of the skin-homing property by the fetal thymic sIEL precursors. In ITK knockout mice, the sIEL precursors could not undergo positive selection-associated upregulation of thymus-exiting and skin-homing molecules sphingosine-1-phosphate receptor 1 and CCR10 and accumulated in the thymus. However, the survival and expansion of sIELs in the skin did not require ITK-transduced TCR signaling, whereas its persistent activation impaired sIEL development by inducing apoptosis. These findings provide insights into molecular mechanisms underlying differential requirements of TCR signaling in peripheral localization and maintenance of the tissue-specific T cells.
authors.affiliation: Department of Veterinary and Biomedical Sciences, Center for Molecular Immunology and Infectious Disease, Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Mingcan
authors.initials: M
authors.lastname: Xia
authors.forename: Qian
authors.initials: Q
authors.lastname: Qi
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
authors.forename: David L
authors.initials: DL
authors.lastname: Wiest
authors.forename: Avery
authors.initials: A
authors.lastname: August
authors.forename: Na
authors.initials: N
authors.lastname: Xiong
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology; D002469:Cell Separation; D005434:Flow Cytometry; D020287:In Situ Nick-End Labeling; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D011505:Protein-Tyrosine Kinases / Q000276:immunology* / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology*; D012867:Skin / Q000166:cytology / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
chemical_list: D016692:Receptors, Antigen, T-Cell, gamma-delta; D011505:Protein-Tyrosine Kinases; C080813:emt protein-tyrosine kinase