Expression of a mannose/fucose membrane lectin on human dendritic cells

Abstract

Expression of a mannoselfucose membrane lectin on human dendritic cellsDendritic cells (DC) are the most efficient antigen presenting cells for T lymphocytes. CDla' CD14-DC with high antigen-presenting capacities can now be obtained easily from adherent peripheral blood monocytes by culture in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4 (Sallusto et al., J . Exp. Med. 1994. 179: 1109). Human macrophages express a membrane lectin, or sugar-specific receptor, which specifically mediates the binding and endocytosis of mannose-and fucose-terminated glycoproteins and is involved in the phagocytosis of pathogens. Asimilar lectin activity was sought on cultured human DC using flow cytometry and confocal microscopy to detect binding and internalization of fluoresceinated neoglycoproteins [bovine serum albumin (BSA) substituted with sugar residues]. Several neoglycoproteins, especially a-L-fucosyl-, a-D-mannosyl-, N,N'-di-acetyl-P-chitobiosyl-and 0-Dglucosyl-BSA, were endocytosed by cultured human CDla' DC as well as by CDla-CD14-cells which were also obtained in the culture. Fuc-BSA and Man-BSA had the same number of binding sites (1.7 x 10h/cell) on CDla' DC, and bound with an affinity constant close to lo7 Vmol. Inhibition experiments indicated that these two neoglycoproteins bound to the same membrane lectin. CDla' and CDla-cells were both labeled by an antiserum specific for the human macrophage mannose receptor. The membrane lectin specific for mannose and fucose that is evidenced in these experiments on cultured DC may be similar to the macrophage membrane lectin or may share functional and structural properties with it. IntroductionDendritic cells (DC) are particularly efficient in presenting antigens to naive as well as to mature T lymphocytes [ 1-31. They initiate primary T cell responses in vivo and in vitro. They can stimulate an allogeneic mixed lymphocyte reaction with a much lower presenting celYeffector cell ratio than unseparated mononuclear cells, and they can present much lower concentrations of antigens than macrophages or nonspecific B lymphocytes [l]. DC are derived from human myeloid-lineage cells and express high levels of MHC class I and MHC class I1 molecules, CD40, CD80 (B7.1) and CD86 (B7.2) co-stimulatory molecules, several

Monocyte-derived dendritic cells have a phenotype comparable to that of dermal dendritic cells and display ultrastructural granules distinct from Birbeck granules

“…Adherent cells were cultured in six-well plates in medium supplemented with 10% FCS containing either low concentrations of interleukins, i.e. 200 U/mL (18 ng/mL) GM-CSF and 50 U/mL (10 ng/mL) IL-4 [20], or high concentrations (800 and 500 U/mL, respectively). The cultures were fed with fresh medium and cytokines every 2-3 days and nonadherent cells, thereafter called monocyte-derived DC, were harvested at day 6 or 7.…”

“…1B) [16] and CD86 (not shown), and down-regulating CD115 (not shown). Thus, monocyte-derived DC cultured with low and high concentrations of interleukins had a similar phenotypic profile, and the concentrations of 200 U/mL GM-CSF and 50 U/mL IL-4 were used throughout our studies [20].…”

“…These progenitors differentiate along two different DC pathways: CD1a-derived DC, which display Birbeck granules and markers specifically expressed on LC in the epidermis, and CD14-derived DC characterized by the expression of CD1a and FXIIIa, like dermal DC [15]. DC can also be obtained in vitro by culturing peripheral blood monocytes in the presence of GM-CSF and interleukin-4 (IL-4) [16][17][18][19][20][21][22][23][24]. The relationship between monocyte-derived DC, CD14-derived DC obtained from cord blood precursors, and the different in vivo DC is still unclear.…”

Lectin-like Ox-LDL Receptor Is Expressed in Human INT-407 Intestinal Cells: Involvement in the Transcytosis of Pancreatic Bile Salt–dependent Lipase

“…This structure, which is highly variable (Sugo et al, 1993) may help BSDL to interact with mannose/fucose lectin receptor (Avraméas et al, 1996). The molecular chaperone Grp94, once associated with BSDL can also be internalized via this receptor and macropinocytosis (Arnold-Schild et al, 1999;Wassenberg et al, 1999).…”

“…For this purpose the effects of various ligands, which have been shown to hinder glycoprotein interaction with specific receptors or to inhibit oxidized-LDL binding to class A and B scavenger receptors and to the lectin-like Ox-LDL receptor (LOX-1; Moriwaki et al, 1998;Shirai et al, 1999), were examined. First of all, to rule out the possibility that BSDL interacted with the cell via the mannose/fucose lectin receptor (Avraméas et al, 1996), we performed competition experiments using mannan as a competitor (Arnold-Schild et al, 1999). No inhibitory effect was observed using this ligand at a concentration of 1 mg/ml ( Figure 4A), whereas 0.3 mg/ml mannan was shown to inhibit completely the uptake of FITC-dextran by the mannose/fucose lectin receptor of dendritic cells (Sallusto et al, 1995).…”