Sialyl lewis x is important in ABO blood antigen determination.
SLex is also important to proper immune response. P-selectin release from Weibel-Palade bodies, on blood vessel endothelial cells, can be induced by a number of factors. One such factor is the response of the endothelial cell to certain bacterial molecules, such as peptidoglycan. P-selectin binds to the SLex structure that is present on neutrophils in the bloodstream and helps to mediate the extravasation of these cells into the surrounding tissue during infection.
O-linked glycans, in particular mucin, have been found to be important in developing normal intestinal microflora. Certain strains of intestinal bacteria bind specifically to mucin, allowing them to colonize the intestine.
Examples of O-linked glycoproteins are:
*Glycophorin, a protein in erythrocyte cell membranes
*Mucin, a protein in saliva involved in formation of dental plaque
*Notch, a transmembrane receptor involved in development and cell fate decisions
*Thrombospondin
*Factor VII
*Factor IX
*Urinary type plasminogen activator