Anti-Le monoclonal antibody SPM 522 recognizes an extended Le epitope.

Insights into the differential binding characteristics of anti-Le and anti-LeLe monoclonal antibodies (mAbs) provide information to develop LeLe-based cancer immunotherapeutics while avoiding anti-Le autoimmune reactions. We characterized the epitope recognized by anti-Le mAb SPM 522. We synthesized the Le 6-aminohexyl glycoside and report experimental evidence of a minor conformation in solution.

Synthesis of Tumor-Associated Le(a)Le(x) Hexasaccharides: Instability of a Thiol-Containing Oligosaccharide in Mass Spectrometry and Hypermetalation Detected by ESI FAIMS.

We report the efficient synthesis of three analogues of the tumor-associated carbohydrate antigen Le(a)Le(x). This hexasaccharide was prepared as a soluble inhibitor hexyl glycoside, as a 6-aminohexyl glycoside for conjugation to proteins, and as a 6-thiohexyl glycoside for immobilization to a gold surface. These three analogues were obtained from a common hexasaccharide intermediate and isolated pure following efficient deprotection reactions that involved metal-dissolving conditions.

Aggregation of a Tetrasaccharide Acceptor Observed by NMR: Synthesis of Pentasaccharide Fragments of the Le(a)Le(x) Tumor-Associated Hexasaccharide Antigen.

We report the synthesis of a tetrasaccharide and two pentasaccharide fragments of the Le(a)Le(x) tumor-associated carbohydrate antigen α-L-Fuc-(1→4)-[β-D-Gal-(1→3)]-β-D-GlcNAc-(1→3)-β-D-Gal-(1→4)-[α-L-Fuc-(1→3)]-β-D-GlcNAc-(1→OR). The choice of protecting groups permitted a one-step global deprotection (Na/NH3(l)). The protected chlorohexyl glycoside pentasaccharide was the precursor to the hexyl glycoside, to be used as a soluble inhibitor, and the aminohexyl glycoside analogue, to be conjugated to proteins for surface immobilization and immunization experiments.

Challenging deprotection steps during the synthesis of tetra- and pentasaccharide fragments of the Le(a)Le(x) tumor-associated hexasaccharide antigen.

We report the convergent synthesis of two novel tetrasaccharide and two novel pentasaccharide fragments of the Le(a)Le(x) TACA: the tetrasaccharides contain neither the galactose at the Le(a) nonreducing end nor the fucose at the Le(x) reducing end; the pentasaccharides only lack the galactose residue at the Le(a) nonreducing end. Two of the analogues were prepared as hexyl glycosides to be used in NMR experiments and as soluble inhibitors in binding studies and two as 6-aminohexyl glycosides to be conjugated to carrier proteins. Our strategy relied on stepwise extensions using excess monosaccharide glycosyl donors (trichloroacetimidates and thioglycosides) in sequential glycosylation reactions.

Matched and mismatched acceptor/donor pairs in the glycosylation of a trisaccharide diol free at O-3 of two N-acylated glucosamine residues.

Reciprocal donor acceptor selectivity (RDAS) and double diastereodifferentiation are two concepts that have been used to explain how a glycosyl acceptor and donor may be 'matched' or 'mismatched' in glycosylation reactions. We describe here how the α-L-fucosylation and β-D-galactosylation of a trisaccharide displaying two equatorial OH groups at C-3 of N-acylated glucosamine units led to different regioselectivities or different 'matched' pairs. These results may be explained under the reciprocal donor acceptor selectivity or double diastereodifferentiation concepts.

Synthesis of 6-thio pseudo glycolipids and their orientation on a gold slide studied by IRRAS.

We have synthesized four 6-thio pseudo glycolipid analogues and assessed how two of them self-assembled on a gold surface. These structures were designed as candidate tethers molecules to anchor bilayer lipid membranes on gold. 6-Deoxy-6-thiogalactose was chosen to anchor the macromolecule to the gold and define an aqueous zone at the gold surface.