title: Human DC-SIGN binds specific human milk glycans.
abstract: Human milk glycans (HMGs) are prebiotics, pathogen receptor decoys and regulators of host physiology and immune responses. Mechanistically, human lectins (glycan-binding proteins, hGBP) expressed by dendritic cells (DCs) are of major interest, as these cells directly contact HMGs. To explore such interactions, we screened many C-type lectins and sialic acid-binding immunoglobulin-like lectins (Siglecs) expressed by DCs for glycan binding on microarrays presenting over 200 HMGs. Unexpectedly, DC-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) showed robust binding to many HMGs, whereas other C-type lectins failed to bind, and Siglec-5 and Siglec-9 showed weak binding to a few glycans. By contrast, most hGBP bound to multiple glycans on other microarrays lacking HMGs. An α-linked fucose residue was characteristic of HMGs bound by DC-SIGN. Binding of DC-SIGN to the simple HMGs 2'-fucosyl-lactose (2'-FL) and 3-fucosyl-lactose (3-FL) was confirmed by flow cytometry to beads conjugated with 2'-FL or 3-FL, as well as the ability of the free glycans to inhibit DC-SIGN binding. 2'-FL had an IC50 of ∼1 mM for DC-SIGN, which is within the physiological concentration of 2'-FL in human milk. These results demonstrate that DC-SIGN among the many hGBP expressed by DCs binds to α-fucosylated HMGs, and suggest that such interactions may be important in influencing immune responses in the developing infant.
authors.affiliation: The Glycomics Center, Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, U.S.A. Program in Microbiology and Molecular Genetics, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, GA 30322, U.S.A.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Noll
authors.affiliation: The Glycomics Center, Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, U.S.A.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yu
authors.affiliation: The Glycomics Center, Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, U.S.A.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lasanajak
authors.affiliation: Abbott Nutrition, Global Discovery R&D, Columbus, OH 43215, U.S.A.
authors.forename: Geralyn
authors.initials: G
authors.lastname: Duska-McEwen
authors.affiliation: Abbott Nutrition, Global Discovery R&D, Columbus, OH 43215, U.S.A.
authors.forename: Rachael H
authors.initials: RH
authors.lastname: Buck
authors.affiliation: The Glycomics Center, Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, U.S.A.
authors.forename: David F
authors.initials: DF
authors.lastname: Smith
authors.affiliation: The Glycomics Center, Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, U.S.A. rcummin1@bidmc.harvard.edu.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Cummings
mesh_terms: D015815:Cell Adhesion Molecules / Q000378:metabolism*; D003713:Dendritic Cells / Q000378:metabolism; D006801:Humans; D037181:Lectins, C-Type / Q000378:metabolism*; D008895:Milk, Human / Q000737:chemistry*; D011134:Polysaccharides / Q000378:metabolism*; D040081:Protein Array Analysis; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000378:metabolism*; D063265:Sialic Acid Binding Immunoglobulin-like Lectins / Q000378:metabolism; D014312:Trisaccharides / Q000378:metabolism; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D015815:Cell Adhesion Molecules; D037181:Lectins, C-Type; D011134:Polysaccharides; D011956:Receptors, Cell Surface; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; D014312:Trisaccharides; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C031420:2'-fucosyllactose
keywords: dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN); glycan microarrays; glycan recognition; glycan-binding proteins; human milk glycans; lectins