title: Efficient uptake of mannosylated proteins by a human Schwann cell line.
abstract: Complex carbohydrate structures are essential molecules of infectious microbes and host cells, and are involved in cell signaling associated with inflammatory and immune responses. The uptake of mannose-tailed glycans is usually carried out by macrophages, dendritic cells (DCs), and other professional phagocytes to trigger MHC class I- and MHC class II-restricted antigen presentation, and to promote T cell effector responses. Since Schwann cells (SCs) have been proposed as immunocompetent cells, we investigated whether a human cell line (ST88-14 cells) could bind mannosylated ligands in a specific manner. The saturation of uptake of mannosylated molecules by ST88-14 cells and the internalization and distribution pathway of these ligands were tested by cytometry and confocal plus electron microscopy, respectively. This uptake showed a dose-dependent increase, the saturation point being reached at high concentrations of mannosyl residues/240 mM mannose. Merging of man/BSA-FITC and S100 labeling showed their partial, but, significant colocalization. Ultrastructural analysis of ST88-14 cells after incubation with HRP-colloidal gold, without or with subsequent chasing at 37C, showed an initial location on the cell surface and temperature- and time-dependent internalization of the probe. Our findings suggest an efficient mannosylated ligand uptake system through putative lectin(s) that may be operational in inflammatory and immune responses.
authors: Federal University of Rio de Janeiro, Institute of Biophysics Carlos Chagas Filho, Laboratory of Developmental Neurobiology, Rio de Janeiro, Brazil.
authors: Wagner
authors: W
authors: Baetas-da-Cruz
authors: Lucinéia
authors: L
authors: Alves
authors: Erick V
authors: EV
authors: Guimarães
authors: Alessandra
authors: A
authors: Santos-Silva
authors: Maria Cristina V
authors: MC
authors: Pessolani
authors: Helene S
authors: HS
authors: Barbosa
authors: Suzana
authors: S
authors: Corte-Real
authors: Leny A
authors: LA
authors: Cavalcante
mesh_terms: D045744:Cell Line, Tumor; D004705:Endocytosis / Q000276:immunology; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006046:Gold / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D037181:Lectins, C-Type / Q000378:metabolism / Q000648:ultrastructure; D008024:Ligands; D008358:Mannose / Q000378:metabolism*; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins / Q000378:metabolism / Q000648:ultrastructure; D011956:Receptors, Cell Surface / Q000378:metabolism / Q000648:ultrastructure; D009418:S100 Proteins / Q000378:metabolism; D012583:Schwann Cells / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D005456:Fluorescent Dyes; D037181:Lectins, C-Type; D008024:Ligands; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D011956:Receptors, Cell Surface; D009418:S100 Proteins; D006046:Gold; D006735:Horseradish Peroxidase; D016650:Fluorescein-5-isothiocyanate; D008358:Mannose