Leucocyte adhesion molecules in inflammatory bowel disease: expression by colonic macrophages

Recent interest has focused on intercellular adhesion molecules and their ligands (the “integrins”), which mediate cell-cell interactions (1). Three leukocyte adhesion glycoproteins share a common β-chain (CD18); the a-chains are LFA-1 (“Lymphocyte Function-associated Antigen-1”; CD11a), MAC-1 (CD11b) and pl50,95 (CD11c), respectively. ICAM-1 (“Intercellular Adhesion Molecule-1”; CD54) is the ligand/receptor for LFA-1. The LFA-l/ICAM-1 interaction of T cells and mononuclear phagocytes is central for antigen presentation, antigen priming and for the mediation of inflammatory responses (2). CD11b and CD11c are receptors for complement C3bi and mediate phagocytosis of opsonized particles and cell binding to endothelium.