Molecules involved in leucocyte endothelial interaction

Figure 2: Schematic representation of the stages of migration of leucocytes from the circulation to an area of injury observable on microscopy. a) denotes the normal situation. In b) the leucocytes are seen to roll along the endothelium, they appear `sticky'. In c) the leucocytes are tightly adherent to the endothelium and in d) they migrate through the endothelium into the interstium. In the transmigration stage there are gaps formed between the endothelial cells and in the underlying basment membrane.

The movement of leucocytes from the circulation to an area of injury is visible on microscopy and goes through several stages in an orderly manner, see figure 2. The interaction of leucocytes with the endothelium is controlled by several families of molecules. These are the selectins, members of the immunoglobulin superfamily and integrins.