Lewis epitopes

Hynes, S.O., Keenan, J.I., Ferris, J.A., Annuk, H., Moran, A.P. Lewis epitopes on outer membrane vesicles of relevance to Helicobacter pylori pathogenesis. Helicobacter 10 (2005) 146-156. 

A similar problem was encountered during the synthesis of the glycans of glyco-dellin-S [36]. The synthesis of Lewis epitope 26 required bis-a-fucosylation of lac-tosamine moiety 24 (Scheme 6). The tri-O-benzylated fucosyl donor 25 provided the tetrasaccharide 26 with acceptable selectivity but unfortunately as an inseparable mixture. Recourse to a bromide donor under halide ion catalysis (as in the previous example) was not successful because the deactivation was so great it made glyco-sylation of the hindered hydroxyls prohibitively slow. Deactivating the donor species by acetylating the 3- and 4-positions (27) [45], however, increased the a-selectivity to the point that the other anomer was unobservable. 

Zhu, J., Pelidou, S. H., Deretzi, G. et al. P0 glycoprotein peptides 56-71 and 180-199 dose-dependently induce aucte and chronic experimental autoimmune neuritis in Lewis rats associated with epitope spreading. /. Neuroimmunol. 114 99-106,2001. 

A similar approach was used in the synthesis of the sialyl Lewis X mimetics of type 85 (Scheme 13.22).66 Protein crystallization,67 conformational studies of sLex in solution68 and in bound form to E- and P-selectin69 as well as the study of structure-function relationships70,71 gave information about the functional groups of the sLex-epitope essential for the binding to the selectins. Synthesized mimetics must contain the three essential hydroxyl functions of the fucose. Sialic acid, galactose, and... 

The same group recently reported the chemical synthesis of sialyl-Lewis X and A epitope analogues containing the N-methyl derivative of (33) [87]. 

A. Hasegawa, T. Ando, A. Kameyama, and M. Kiso, Stereocontrolled synthesis of sialyl Lewis X epitope and its ceramide derivative, J. Carbohydr. Chem. 11 645 (1992). 

C. Foxall, S. R. Watson, D. Dowbenko, C. Fennie, L. A. Lasky, M. Kiso, A. Hasegawa, D. Asa, and B. K. Brandley, The three members of the selectin receptor family recognize a common carbohydrate epitope, the sialyl Lewis X oligosaccharide, J. Cell Biol. 7/7 895 (1992). 

Fig. 21.1. Glycosphingolipids of S. mansoni cercariae. Data on the glycosphingolipid structures are compiled as described in Wuhrer etal. (2000b) [1] and (2000c) [2], Lewis X and pseudo-Lewis Y epitopes are boxed. Cer, ceramide.

TFie Lewis X-epitope and the Fiost-parasite relationship 413... 

Gargiulo, V., Garozzo, D., Lanzetta, R., Molinaro, A., Sturiale, L., Castro, C.D., Parrilli, M. Rhizobium rubi A gram-negative phytopathogenic bacterium expressing the Lewis B epitope on the outer core of its lipoohgosaccharide fraction. ChemBioChem 9 (2008) 1830-1835. 

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