title: Phenotypic and ultrastructural properties of antigen-presenting cells involved in contact sensitization of normal and UV-irradiated mice.
abstract: We investigated the surface phenotype and localization of hapten in antigen-presenting cells involved in the induction of contact hypersensitivity or tolerance. Dendritic cells collected 18 h earlier from the draining lymph nodes of mice sensitized with fluorescein isothiocyanate (FITC), which induce contact hypersensitivity upon injection into the foot-pads of naive mice, stimulated proliferation of lymphocytes from FITC-specific T-cell lines. By immunoelectron microscopy, these cells expressed high amounts of surface Ia molecules but had a negligible amount of FITC on the cell membrane. The majority of the FITC was localized in discrete structures in the cytoplasm, including mitochondria, endocytic vesicles, lysosomes, and cored tubules. In contrast, lymph node cells conjugated with FITC in vitro did not stimulate proliferation of FITC-specific T cells and showed a heavy, uniform distribution of FITC throughout the cytoplasm. Draining lymph node cells from mice exposed to ultraviolet (UV) radiation and then sensitized by applying FITC to the UV-irradiated skin, which induce tolerance upon injection into naive mice, induced significantly less proliferation of FITC-specific T cells than draining lymph node cells from unirradiated mice. The differences in activity of these cells, relative to draining lymph node cells from unirradiated, FITC-sensitized mice could not be attributed to a decreased number of Ia+ dendritic cells in the DLN, decreased surface expression of Ia molecules on these cells, or an alteration in the intracellular localization of hapten. However, a significantly higher percentage of the FITC+ dendritic cells from UV-irradiated mice expressed mac-1, -2, and -3 and F4/80 macrophage markers than did those from unirradiated animals, and fewer cells contained Birbeck granules, suggesting that a different population of Ia+ antigen-presenting cells may reach the draining lymph nodes of UV-irradiated mice.
authors.affiliation: Department of Immunology, University of Texas M. D. Anderson Cancer Center, Houston 77030.
authors.forename: C D
authors.initials: CD
authors.lastname: Bucana
authors.forename: J M
authors.initials: JM
authors.lastname: Tang
authors.forename: K
authors.initials: K
authors.lastname: Dunner
authors.forename: F M
authors.initials: FM
authors.lastname: Strickland
authors.forename: M L
authors.initials: ML
authors.lastname: Kripke
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000473:pathology* / Q000528:radiation effects / Q000648:ultrastructure*; D003713:Dendritic Cells / Q000528:radiation effects; D003877:Dermatitis, Contact / Q000473:pathology*; D004853:Epoxy Resins; D005260:Female; D016650:Fluorescein-5-isothiocyanate; D006241:Haptens / Q000032:analysis; D008198:Lymph Nodes / Q000737:chemistry / Q000473:pathology; D051379:Mice; D008809:Mice, Inbred C3H; D008854:Microscopy, Electron / Q000379:methods; D010641:Phenotype; D012867:Skin / Q000737:chemistry / Q000473:pathology / Q000528:radiation effects; D013601:T-Lymphocytes / Q000473:pathology / Q000528:radiation effects / Q000648:ultrastructure
chemical_list: D004853:Epoxy Resins; D006241:Haptens; C004875:EPON; D016650:Fluorescein-5-isothiocyanate