Description: Leukocyte-Endothelial Cell Adhesion Molecule-1 belongs to the selectin family of adhesion molecule. Together with E-selectin, P-selectin and L-selectin mediates the initial interactions of leukocytes with endothelial cells.
Selectins guide non-activated polymorphonuclear cells to the areas of inflammation in creating first, loose contacts with the endothelial layer. L-selectin in this aspect mediates rolling of PMN's on endothelial cells. The potential binding partners of L-selectin carry a negative charge, probably a sialic acid and/or sulphate, and may contain mannose and fucose. In addition, L-selectin may also interact with E-selectin which is expressed on cytokine-activated endothelial cells. L-selectin is constitutively expressed on most leukocytes in a seemingly functional form. It is required for the binding of lymphocytes to the high endothelial venules of peripheral lymph nodes and for the invasion of neutrophils into sites of inflammation.
When neutrophils are activated, L-selectin is shed by proteolytic cleveage near the transmembrane span. Lymphocytes and monocytes can also shed L-selectin upon activation although the kinetics are significantly lower. A broad range of activating agents are effective in inducing this response. The shed form of sL-selectin is functionally active and at high concentrations can inhibit leukocyte attachment to endothelium. The main source for sL-selectin in serum seems to be tissue localized leukocytes.
