title: Real-time visualization of macromolecule uptake by epidermal Langerhans cells in living animals.
abstract: As a skin-resident member of the dendritic cell family, Langerhans cells (LCs) are generally regarded to function as professional antigen-presenting cells. Here we report a simple method to visualize the endocytotic activity of LCs in living animals. BALB/c mice received subcutaneous injection of FITC-conjugated dextran (DX) probes into the ear skin and were then examined under confocal microscopy. Large numbers of FITC(+) epidermal cells became detectable 12-24 hours after injection as background fluorescence signals began to disappear. Most (>90%) of the FITC(+) epidermal cells expressed Langerin, and >95% of Langerin(+) epidermal cells exhibited significant FITC signals. To assess intracellular localization, Alexa Fluor 546-conjugated DX probes were locally injected into IAβ-enhanced green fluorescent protein (EGFP) knock-in mice and Langerin-EGFP-diphtheria toxin receptor mice--three dimensional rotation images showed close association of most of the internalized DX probes with major histocompatibility complex (MHC) class II molecules, but not with Langerin molecules. These observations support the current view that LCs constantly sample surrounding materials, including harmful and innocuous antigens, at the environmental interface. Our data also validate the potential utility of the newly developed imaging approach to monitor LC function in wild-type animals.
authors: Department of Medical Microbiology and Immunology, University of Toledo College of Medicine, Toledo, Ohio 43614-5806, USA.
authors: Rachel E
authors: RE
authors: Frugé
authors: Colleen
authors: C
authors: Krout
authors: Ran
authors: R
authors: Lu
authors: Hironori
authors: H
authors: Matsushima
authors: Akira
authors: A
authors: Takashima
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D003911:Dextrans / Q000378:metabolism; D004705:Endocytosis; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D007801:Langerhans Cells / Q000166:cytology* / Q000378:metabolism*; D037181:Lectins, C-Type / Q000032:analysis; D037241:Mannose-Binding Lectins / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal / Q000379:methods; D011806:Quinolinium Compounds / Q000378:metabolism
chemical_list: C481052:Alexa fluor 546; D000954:Antigens, Surface; C498497:Cd207 protein, mouse; D003911:Dextrans; D005456:Fluorescent Dyes; D000949:Histocompatibility Antigens Class II; D037181:Lectins, C-Type; D037241:Mannose-Binding Lectins; D011806:Quinolinium Compounds; C485184:enhanced green fluorescent protein; C015219:fluorescein isothiocyanate dextran; D049452:Green Fluorescent Proteins; D016650:Fluorescein-5-isothiocyanate