SELECTINS, T-CELL ROLLING AND INFLAMMATION

The selectins, a family of Ca2+-dependent lectins, are expressed on in flamed vascular endothelium and some leukocyte subsets, and mediate ad hesive contacts between blood cells and vessel walls. These interactio ns are loose and reversible, operate under conditions of shear flow, a nd result in leukocyte rolling along the vessel wall. The structure of the selectins and their ligands makes them uniquely suited for suppor ting the type of bond formation and dissociation that must prevail in order for a cell to be able to roll under conditions of flow. Because rolling precedes (and appears to be essential for) the integrin-mediat ed firm arrest before extravasation in response to inflammatory or inf ectious stimuli, inhibition of selectin function has potential for ant i-inflammatory therapy, but also presents some significant challenges because of the complexity of the processes involved.