Contributions of Selectins during Vascular Adhesion in Blood Flow

998 Words Feb 20th, 2018 4 Pages
Step I is the initial low-affinity rolling interaction that is mediated by all three selectins. Step II involved activation of leukocytes that alter concentration gradients of various chemotactic factors. Step III is the high-affinity adhesion, change in shape of leukocyte, and finally extravasation. Figure 2 left out another important factor of selectin’s role in inflammation: PSGL-1. PSGL-1 on the plasma memebranes of neutrophils or monocytes binds to P-selectin translocated to the surfaces of inflamed endothelial cells (Zimmerman 2001). The binding of PSGL-1 by P-selectin is particularly important in the initial steps of inflammation. This intereaction is responsible for the recruitment of inflammatory leukocyte (Ley 2013). There have been two different approaches in vivo to investigate the contributions of selectins during vascular adhesion in blood flow. The first investigation used activated endotheial cells under conditions of shear to demonstrate that L-selectin mediate initial binding of leukocytes to the endothelium (Lasky 1992). Initially there is low-affinity binding followed by higher affinity binding mediated by leukocyte integrins. A second approach showed that isolated, immobilized P-selectin could mediate rolling of leukocytes in laminar flow chambers when shear increased (Lasky 1992). Although this was done in vitro, the rolling appears to mimic the mechanism seen under a microscopy…
Open Document