title: Thymus-independent generation of Thy-1+ epidermal cells from a pool of Thy-1- bone marrow precursors.
abstract: Thy-1+ dendritic epidermal cells (Thy-1+ DEC) and immature thymocytes share several phenotypic features: CD45+, Thy-1+, asialo-GM1+, CD3+, CD4-, and CD8-. In view of this similarity, it has been suggested that the epidermis may be a site of either post-thymic or extra-thymic T-cell development. In order to address this issue, we used C3H/He/Han (Thy-1.2)----AKR/Ola (Thy-1.1) radiation bone marrow chimeras. Animals were first either thymectomized or sham-thymectomized, then lethally irradiated (750R) and, finally, reconstituted with allogeneic bone marrow cells previously depleted of Thy-1-bearing cells. Six weeks after bone marrow transplantation, spleens and lymph nodes of sham-treated animals, but not of thymectomized animals, contained large numbers of CD3+ donor-type Thy-1+ cells. The epidermis of both thymectomized and sham-treated animals contained not only many recipient-type CD3+, Thy-1+ DEC, but also small numbers of CD3-, donor-type Thy-1+ cells. After 4 months, the frequency of donor cells had greatly increased, but they still lacked CD3 antigens. Most of the donor cells had a rounded shape, but some exhibited a dendritic configuration. These results demonstrate that Thy-1- bone marrow-derived precursors of Thy-1+ DEC can migrate to the epidermis without thymic influence and yet acquire Thy-1 antigens during their journey. Although donor-type Thy-1+ epidermal cells failed to mature into CD3+ dendritic epidermal cells, the experimental model used in this study may be a versatile tool for studying the influence of thymic and extrathymic epithelia on T-cell maturation.
authors.affiliation: Division of Cutaneous Immunobiology, University of Vienna Medical School, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Honjo
authors.forename: A
authors.initials: A
authors.lastname: Elbe
authors.forename: G
authors.initials: G
authors.lastname: Steiner
authors.forename: I
authors.initials: I
authors.lastname: Assmann
authors.forename: K
authors.initials: K
authors.lastname: Wolff
authors.forename: G
authors.initials: G
authors.lastname: Stingl
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology*; D000955:Antigens, T-Independent / Q000276:immunology*; D001853:Bone Marrow / Q000276:immunology / Q000648:ultrastructure; D001854:Bone Marrow Cells; D017252:CD3 Complex; D002678:Chimera / Q000276:immunology; D000078404:Epidermal Cells; D004817:Epidermis / Q000276:immunology / Q000648:ultrastructure; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology / Q000648:ultrastructure; D008297:Male; D051379:Mice; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D016201:Receptors, Lymphocyte Homing / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology / Q000648:ultrastructure; D018800:Thy-1 Antigens; D013934:Thymectomy; D013950:Thymus Gland / Q000502:physiology* / Q000601:surgery
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D000955:Antigens, T-Independent; D017252:CD3 Complex; D011948:Receptors, Antigen, T-Cell; D016201:Receptors, Lymphocyte Homing; D018800:Thy-1 Antigens