ABSTRACT
Leukocyte adhesion involves the leukocyte-specific integrins CD11a/CD18, CD11b/CD18 and CD11c/CD18, which bind to intercellular adhesion molecules (ICAM). Three ICAM have been described, and are expressed on leukocytes and various other cells, but are absent from red cells. Here, we show that the red cell Landsteiner-Wiener (LW) blood group glycoprotein is an ICAM which binds to the leukocyte-specific integrins. This finding has important implications in red cell physiology.
Subject(s)
Blood Group Antigens/chemistry , CD11 Antigens/blood , CD18 Antigens/blood , Cell Adhesion Molecules/blood , Erythrocytes/chemistry , Integrins/metabolism , Blood Group Antigens/isolation & purification , Blood Group Antigens/metabolism , Cell Adhesion Molecules/chemistry , Cell Adhesion Molecules/isolation & purification , Humans , Protein BindingABSTRACT
Leukocyte adhesion involves at least three molecular families of adhesion proteins: the leukocyte integrins CD11/CD18, the intercellular adhesion molecules (ICAMs) and the carbohydrate-binding L-, E- and P-selectins. The intercellular adhesion molecules are well-known ligands for the CD11/CD18 integrins. We now show that E-selectin specifically binds to the sialyl Lex carbohydrate epitopes of leukocyte integrins. Thus, the different families of leukocyte adhesion molecules form an integrated adhesion network.
Subject(s)
Antigens, CD/metabolism , Cell Adhesion Molecules/metabolism , Integrins/metabolism , Leukocytes/chemistry , CD11 Antigens , CD18 Antigens , Cell Adhesion , Cell Adhesion Molecules/genetics , Cell Line , E-Selectin , Epitopes/metabolism , Leukocytes/immunology , Lewis Blood Group Antigens/immunology , Recombinant Proteins/metabolism , TransfectionABSTRACT
During the past few years it has become increasingly evident that specific oligosaccharides in glycoproteins/glycolipids may play a central role in mammalian cell adhesion. This review deals with two of the best studied systems, the interaction of sperm cells with the Zona pellucida layer surrounding mammalian eggs, and the binding of leukocytes to endothelial cells. In the sperm cell-Zona pellucida system, it is known that a specific oligosaccharide(s) in the Zona pellucida glycoprotein 3 is responsible for binding. In the leukocyte-endothelial cell interaction, sialyl Le(x), sialyl Le(a), sulfatides, and other less well-defined sugar structures are involved in cellular binding. Oligosaccharides involved in these adhesion events may turn out to have clinically important applications.
