title: Clustered carbohydrates as a target for natural killer cells: a model system.
abstract: Membrane-associated oligosaccharides are known to take part in interactions between natural killer (NK) cells and their targets and modulate NK cell activity. A model system was therefore developed using synthetic glycoconjugates as tools to modify the carbohydrate pattern on NK target cell surfaces. NK cells were then assessed for function in response to synthetic glycoconjugates, using both cytolysis-associated caspase 6 activation measured by flow cytometry and IFN-gamma production. Lipophilic neoglycoconjugates were synthesized to provide their easy incorporation into the target cell membranes and to make carbohydrate residues available for cell-cell interactions. While incorporation was successful based on fluorescence monitoring, glycoconjugate incorporation did not evoke artifactual changes in surface antigen expression, and had no negative effect on cell viability. Glycoconjugates contained Le(x), sulfated Le(x), and Le(y) sharing the common structure motif trisaccharide Le(x) were revealed to enhance cytotoxicity mediated specifically by CD16 +CD56+NK cells. The glycoconjugate effects were dependent on saccharide presentation in a polymeric form. Only polymeric, or clustered, but not monomeric glycoconjugates resulted in alteration of cytotoxicity in our system, suggesting that appropriate presentation is critical for carbohydrate recognition and subsequent biological effects.
authors.affiliation: Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya, 16/10, Moscow 117997, Russia. lenkovalen@mail.ru
authors.forename: Elena I
authors.initials: EI
authors.lastname: Kovalenko
authors.forename: Elena
authors.initials: E
authors.lastname: Abakushina
authors.forename: William
authors.initials: W
authors.lastname: Telford
authors.forename: Veena
authors.initials: V
authors.lastname: Kapoor
authors.forename: Elena
authors.initials: E
authors.lastname: Korchagina
authors.forename: Sergei
authors.initials: S
authors.lastname: Khaidukov
authors.forename: Irina
authors.initials: I
authors.lastname: Molotkovskaya
authors.forename: Alexander
authors.initials: A
authors.lastname: Sapozhnikov
authors.forename: Pavel
authors.initials: P
authors.lastname: Vlaskin
authors.forename: Nicolai
authors.initials: N
authors.lastname: Bovin
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D002470:Cell Survival; D003601:Cytotoxicity Tests, Immunologic; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D019084:Fluorescent Antibody Technique, Indirect; D005456:Fluorescent Dyes; D005562:Formazans / Q000378:metabolism; D006001:Glycoconjugates / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D006017:Glycolipids / Q000737:chemistry / Q000378:metabolism*; D018922:HL-60 Cells; D006801:Humans; D007202:Indicators and Reagents / Q000378:metabolism; D007371:Interferon-gamma / Q000096:biosynthesis; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000276:immunology*; D015448:Leukemia, B-Cell / Q000473:pathology; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D011419:Propidium / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D005456:Fluorescent Dyes; D005562:Formazans; D006001:Glycoconjugates; D006017:Glycolipids; D007202:Indicators and Reagents; D011419:Propidium; D007371:Interferon-gamma; D016650:Fluorescein-5-isothiocyanate