HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Efficient uptake of mannosylated proteins by a human Schwann cell line

Wagner Baetas-da-Cruz1,2, Lucinéia Alves3, Erick V. Guimarães2, Alessandra Santos-Silva1, Maria Cristina V. Pessolani3, Helene S. Barbosa2, Suzana Corte-Real2 and Leny A. Cavalcante1

1Federal University of Rio de Janeiro, Institute of Biophysics Carlos Chagas Filho, Laboratory of Developmental Neurobiology, Rio de Janeiro, Brazil, 2Institute Oswaldo Cruz, Laboratory of Structural Biology, Rio de Janeiro, Brazil and 3Institute Oswaldo Cruz, Laboratory of Cellular Microbiology, Rio de Janeiro, Brazil
WBC, SC-R, and LAC contributed equally to this paper.

Offprint requests to: Dr. Leny A. Cavalcante, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Av. Carlos Chagas Filho, 373 – CCS, Bloco G, 21941-902 Rio de Janeiro, Brazil. e-mail: Leny@biof.ufrj.br; Lacav@abc.org.br


Summary. 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/240mM 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 37°C, 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
. Histol Histopathol 24, 1029-1034 (2009)

Key words: Pattern recognition receptors, Mannose receptor, Endocytic compartments

DOI: 10.14670/HH-24.1029