Enzymatic synthesis of alpha3'sialylated and multiply alpha3fucosylated biantennary polylactosamines. A bivalent [sialyl diLex]-saccharide inhibited lymphocyte-endothelium adhesion organ-selectively.
Multifucosylated sialo-polylactosamines are known to be high affinity ligands for E-selectin. PSGL-1, the physiological ligand of P-selectin, is decorated in HL-60 cells by a sialylated and triply fucosylated polylactosamine that is believed to be of functional importance. Mimicking some of these saccharide structures, we have synthesized enzymatically a bivalent [sialyl diLex]-glycan, Neu5Acalpha2-3'Lexbeta1-3'Lexbeta1-3'(Neu5Acalpha2-3'Lexbeta1-3Lexbe ta1-6')LN [where Neu5Ac is N-acetylneuraminic acid, Lex is the trisaccharide Galbeta1-4(Fucalpha1-3)GlcNAc and LN is the disaccharide Galbeta1-4GlcNAc]. Several structurally related, novel polylactosamine glycans were also constructed. The inhibitory effects of these glycans on two L-selectin-dependent, lymphocyte-to-endothelium adhesion processes of rats were analysed in ex-vivo Stamper-Woodruff binding assays. The IC50 value of the bivalent [sialyl diLex]-glycan at lymph node high endothelium was 50 nm, but at the capillaries of rejecting cardiac allografts it was only 5 nm. At both adhesion sites, the inhibition was completely dependent on the presence of fucose units on the sialylated LN units of the inhibitor saccharide. These data show that the bivalent [sialyl diLex]-glycan is a high affinity ligand for L-selectin, and may reduce extravasation of lymphocytes at sites of inflammation in vivo without severely endangering the normal recirculation of lymphocytes via lymph nodes.
Toppila
S
S
Haartman Institute, Department of Bacteriology and Immunology, Institute of Biotechnology, University of Helsinki, Finland.
Renkonen
R
R
Penttilä
L
L
Natunen
J
J
Salminen
H
H
Helin
J
J
Maaheimo
H
H
Renkonen
O
O
D000606:Amino Sugars / Q000096:biosynthesis* / Q000737:chemistry* / Q000494:pharmacology; D000818:Animals; D002240:Carbohydrate Sequence; D002448:Cell Adhesion / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects; D005643:Fucose / Q000737:chemistry; D006084:Graft Rejection / Q000517:prevention & control; D018922:HL-60 Cells; D016027:Heart Transplantation; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000737:chemistry; D011134:Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011920:Rats, Inbred WF; D014184:Transplantation, Homologous
D000606:Amino Sugars; D011134:Polysaccharides; C066929:polylactosamine; D005643:Fucose; D019158:N-Acetylneuraminic Acid