Lewis Glyco-Epitopes: Structure, Biosynthesis, and Functions

• DOI: 10.1007/978-1-4419-7877-6_4
• Publication Date: 2011-05-26T21:07:45Z
• Authors: Hui-Li Chen
• Keywords: Sialyl-Lewis X

The Lewis glyco-epitope, also called the Lewis antigen (Le), is a series of α1→3/α1→4 fucosylated oligosaccharide epitopes derived from the Galβ1→3/1→4GlcNAcβ1→R carbohydrate backbone and that have been identified on the surface of certain eukaryotic and prokaryotic cells. The α1→3 or α1→4 fucose in Lewis glyco-epitopes is attached on GlcNAc residue, and the Gal residue can be unsubstituted, α2→3 sialylated, α1→2 fucosylated, or sulfated. They are structurally related to the sugar determinants of the human ABH(O) blood group antigen system. The “Lewis” blood group antigen was named for a family of individuals suffering from a red blood cell incompatibility, which led to the discovery of this blood group [1]. Recently, the biological significance of Lewis epitopes has been widely studied. Some of them became recognized as tumor markers and are being used in the clinical diagnosis and prognosis of certain cancers, and others were found to be involved in the pathogenesis of stomach disorders and embryo development. More interestingly, Lewis epitopes have been implicated in the regulation of cell biological events, such as cell signaling, growth, apoptosis, adhesion, and migration. This review will introduce some of the major advances in the research of the structure and function of these Lewis epitopes.