Oxidized-LDL (oxLDL) triggers the upregulation of endothelial cell-adhesion-molecule expression, passing leukocytes and lymphocytes attach to endothelial cells via tethering to the CAMs. Selectins are CAMs specific for leukocyte-vascular interactions. P-selectin is stored in intracellular vesicles in unstimulated endothelial cells. Activation of endothelial cells results in the trafficking of the vesicles containing P-selectin to the cell surface. Surface expression of P-selecting forms week interactions with passing leukocytes, which are slowed but not stopped. For tight adhesion to occur β2 containing integrins must be activated. Activation of the αmβ2 integrin (expressed in monocytes), induced by PAF. Binding of PAF to its receptor on immune-cells activates the β2-integrins through Rho. Activated integrins then bind to ICAMs, expressed on the surface of endothelial cells, allowing tight adhesion.