Table 1.
Summary of the major molecular determinants of the leucocyte adhesion cascade
| Molecule | Expression | Role in Adhesion Cascade |
|---|---|---|
| L selectin | Leucocytes | Rolling |
| P selectin | Endothelial cells and Platelets | Rolling |
| E selectin | Endothelial cells | Rolling |
| Selectin Ligands | ||
| Sialyl Lewisx | Various cells regulated by fucosyl transferase VII | Ligand for all selectins which is presented on the following molecules : |
| PSGL-1 | Leucocytes | Main ligand for P-selectin but binds all selectins |
| PNAd | High endothelial venules | Ligand for L-selectin |
| CLA | Skin homing leucocytes | Ligand for E-selectin |
| β2 Integrins | Firm adhesion and transmigration | |
| αL β2 | Leucocytes | |
| αM β2 | Myeloid cells | |
| α4 Integrins | Rolling and Firm Adhesion | |
| α4 β1 | Leucocytes except neutrophils | |
| α4 β7 | Gut homing leucocytes | |
| Immunoglobulin Superfamily | ||
| ICAM-1 | Increased expression on endothelial cells with cytokines | Ligand for β2 Integrins: firm adhesion and transmigration |
| ICAM-2 | Constitutive on endothelium | Ligand for β2 integrins: firm adhesion and transmigration |
| VCAM-1 | Induced expression on endothelial cells with cytokines | Ligand for α4 Integrins: rolling and firm adhesion |
| MAdCAM-1 | High endothelial venules on gut associated lymphoid tissue | Ligand for L-selectin and rolling and α4 β7: firm adhesion |
| PECAM-1 | Endothelial cells and leucocytes | Transmigration |
| JAM A,B,C | Endothelial cells | Transmigration |
PSGL-1, P-selectin glycoprotein ligand 1; PNAd, Peripheral-node addressin; CLA, Cutaneous lymphocyte antigen; ICAM-1, Intercellular adhesion molecule 1; ICAM-2, Intercellular adhesion molecule 2; VCAM-1, Vascular cell adhesion molecule 1; MAdCAM-1, Mucosal vascular addressin cell adhesion molecule 1; PECAM-1, Platelet-endothelial cell adhesion molecule 1; JAM, Junctional adhesion molecule.