Sialyl Lewis X (sLex):Biological functions, synthetic methods and therapeutic implications

Abstract

Carbohydrates are shown to be crucial to several biological processes. They are essential mediators of cell-cell recognition processes. Among them, Sialyl Lewis X (sLe^x) is a very significant structure in the human body. It is a critical tetrasaccharide that plays a pivotal role in various biological processes, including cell adhesion, immune response, and cancer metastasis. Known as the blood group antigen, sLe^x is also referred to as cluster of differentiation 15s (CD15s) or stage-specific embryonic antigen 1 (SSEA-1). sLe^x is not only a prominent blood group antigen, but also involved in the attraction of sperm to the egg during fertilization, prominently displayed at the terminus of glycolipids on the cell surface. By describing the synthetic methods and biological functions of sLe^x, this review underscores the importance of sLe^x in both fundamental and applied sciences and its potential to impact clinical practice.