title: Identification of a novel lymphoid population in the murine epidermis.
abstract: T cell progenitors are known to arise from the foetal liver in embryos and the bone marrow in adults; however different studies have shown that a pool of T cell progenitors may also exist in the periphery. Here, we identified a lymphoid population resembling peripheral T cell progenitors which transiently seed the epidermis during late embryogenesis in both wild-type and T cell-deficient mice. We named these cells ELCs (Epidermal Lymphoid Cells). ELCs expressed Thy1 and CD2, but lacked CD3 and TCRαβ/γδ at their surface, reminiscent of the phenotype of extra- or intra- thymic T cell progenitors. Similarly to Dendritic Epidermal T Cells (DETCs), ELCs were radioresistant and capable of self-renewal. However, despite their progenitor-like phenotype and expression of T cell lineage markers within the population, ELCs did not differentiate into conventional T cells or DETCs in in vitro, ex vivo or in vivo differentiation assays. Finally, we show that ELC expressed NK markers and secreted IFN-γ upon stimulation. Therefore we report the discovery of a unique population of lymphoid cells within the murine epidermis that appears related to NK cells with as-yet-unidentified functions.
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore.
authors.forename: Francisca F
authors.initials: FF
authors.lastname: Almeida
authors.affiliation: RIKEN Center for Integrative Medical Sciences (IMS), Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Tenno
authors.affiliation: Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Joanna
authors.initials: J
authors.lastname: Brzostek
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore.
authors.forename: Jackson LiangYao
authors.initials: JL
authors.lastname: Li
authors.affiliation: Institute of Immunology, University Clinics Ulm, Ulm, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Allies
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Hoeffel
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore.
authors.forename: Peter
authors.initials: P
authors.lastname: See
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore.
authors.forename: Lai Guan
authors.initials: LG
authors.lastname: Ng
authors.affiliation: Institute of Immunology, University Clinics Ulm, Ulm, Germany.
authors.forename: Hans Jörg
authors.initials: HJ
authors.lastname: Fehling
authors.affiliation: Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Nicholas R J
authors.initials: NR
authors.lastname: Gascoigne
authors.affiliation: RIKEN Center for Integrative Medical Sciences (IMS), Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Taniuchi
authors.affiliation: Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (A*STAR), 138648, Singapore.
authors.forename: Florent
authors.initials: F
authors.lastname: Ginhoux
mesh_terms: D000818:Animals; D018801:CD2 Antigens / Q000378:metabolism; D017252:CD3 Complex / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D018920:Coculture Techniques; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D036641:Microscopy, Fluorescence, Multiphoton; D010641:Phenotype; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018800:Thy-1 Antigens / Q000378:metabolism
chemical_list: D018801:CD2 Antigens; D017252:CD3 Complex; D018398:Homeodomain Proteins; D007376:Interleukin-2; D016692:Receptors, Antigen, T-Cell, gamma-delta; D018800:Thy-1 Antigens; C064658:RAG-1 protein; D007371:Interferon-gamma