Molecular mechanisms of leucocyte rolling and adhesion to microvascular endothelium.

Leucocyte accumulation and activation can lead to tissue injury subsequent to ischaemic insults and reperfusion. Post ischaemic leucocyte recruitment requires the coordinated function of at least four sets of adhesion receptors. Leucocyte rolling in microvessels is mediated by the selectin family of adhesion molecules and their carbohydrate ligands, while firm adhesion and transendothelial migration requires binding of integrin molecules on leucocytes to molecules of the immunoglobulin superfamily expressed on endothelial cells. Adhesion processes are exquisitely regulated at the transcriptional level, but also by conformational changes of proteins and enzymatic modifications of carbohydrate ligands. This article reviews the current knowledge on the function and regulation of adhesion molecules pertinent to leucocyte recruitment.