Description
Introduction: P-selectin is a cell adhesion molecule (CAM) on the surfaces of activated endothelial cells, which line the inner surface of blood vessels, and activated platelets. In unactivated endothelial cells, it is stored in granules Weibel-Palade bodies, and alpha-granules in unactivated platelets. P-selectin plays an essential role in the initial recruitment of leukocytes (white blood cells) to the site of injury during inflammation. Thrombin is one trigger which can stimulate endothelial-cell release of P-selectin and recent studies suggest an additional Ca2+-independent pathway involved in release of P-selectin. Ligands for P-selectin on eosinophils and neutrophils are similar sialylated, protease-sensitive, endo-beta-galactosidase-resistant structures, clearly different than those reported for E-selectin, and suggest disparate roles for P-selectin and E-selectin during recruitment during inflammatory responses. P-selectin attaches to the actin cytoskeleton through anchor proteins that are still poorly characterized.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to sP-selectin. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for sP-selectin and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain sP-selectin, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm +/- 2 nm. The concentration of sP-selectin in the samples is then determined by comparing the O.D. of the samples to the standard curve