title: Human epidermal Langerhans cells replenish skin xenografts and are depleted by alloreactive T cells in vivo.
abstract: Epidermal Langerhans cells (LC) are potent APCs surveying the skin. They are crucial regulators of T cell activation in the context of inflammatory skin disease and graft-versus-host disease (GVHD). In contrast to other dendritic cell subtypes, murine LC are able to reconstitute after local depletion without the need of peripheral blood-derived precursors. In this study, we introduce an experimental model of human skin grafted to NOD-SCID IL2Rγ(null) mice. In this model, we demonstrate that xenografting leads to the transient loss of LC from the human skin grafts. Despite the lack of a human hematopoietic system, human LC repopulated the xenografts 6 to 9 wk after transplantation. By staining of LC with the proliferation marker Ki67, we show that one third of the replenishing LC exhibit proliferative activity in vivo. We further used the skin xenograft as an in vivo model for human GVHD. HLA-disparate third-party T cells stimulated with skin donor-derived dendritic cells were injected intravenously into NOD-SCID IL2Rγ(null) mice that had been transplanted with human skin. The application of alloreactive T cells led to erythema and was associated with histological signs of GVHD limited to the transplanted human skin. The inflammation also led to the depletion of LC from the epidermis. In summary, we provide evidence that human LC are able to repopulate the skin independent of blood-derived precursor cells and that this at least partly relates to their proliferative capacity. Our data also propose xeno-transplantation of human skin as a model system for studying the role of skin dendritic cells in the efferent arm of GVHD.
authors.affiliation: Department of Hematology, Oncology, and Pneumology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Hemmerling
authors.forename: Joanna
authors.initials: J
authors.lastname: Wegner-Kops
authors.forename: Esther
authors.initials: E
authors.lastname: von Stebut
authors.forename: Diana
authors.initials: D
authors.lastname: Wolff
authors.forename: Eva M
authors.initials: EM
authors.lastname: Wagner
authors.forename: Udo F
authors.initials: UF
authors.lastname: Hartwig
authors.forename: Maya C
authors.initials: MC
authors.lastname: André
authors.forename: Matthias
authors.initials: M
authors.lastname: Theobald
authors.forename: Rudolf E
authors.initials: RE
authors.lastname: Schopf
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Herr
authors.forename: Ralf G
authors.initials: RG
authors.lastname: Meyer
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000473:pathology / Q000637:transplantation; D016923:Cell Death / Q000276:immunology / Q000528:radiation effects; D002454:Cell Differentiation / Q000276:immunology / Q000528:radiation effects; D002465:Cell Movement / Q000276:immunology / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004817:Epidermis / Q000276:immunology* / Q000473:pathology / Q000637:transplantation; D005260:Female; D006086:Graft vs Host Disease / Q000276:immunology / Q000473:pathology; D006801:Humans; D007801:Langerhans Cells / Q000276:immunology* / Q000473:pathology / Q000637:transplantation; D008213:Lymphocyte Activation / Q000276:immunology* / Q000528:radiation effects; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D008822:Mice, Transgenic; D016038:Skin Transplantation / Q000276:immunology* / Q000473:pathology; D014183:Transplantation, Heterologous / Q000276:immunology* / Q000473:pathology