Description
Introduction: VCAM-1 (vascular cell adhesion molecule-1), also known as CD106, is the name of both a human gene and its protein product which have a considerable role in the human immune system. The VCAM-1 protein mediates the adhesion of lymphocytes, monocytes, eosinophils, and basophils to vascular endothelium. It also functions in leukocyte-endothelial cell signal transduction, and it may play a role in the development of atherosclerosis and rheumatoid arthritis. Upregulation of VCAM-1 in endothelial cells by cytokines occurs as a result of increased gene transcription (e.g., in response to Tumor necrosis factor-alpha (TNF-alpha) and Interleukin-1 (IL-1)) and through stabilization of Messenger RNA (mRNA) (e.g., Interleukin-4 (IL-4)). The promoter region of the VCAM-1 gene contains functional tandem NF-kappaB (nuclear factor-kappa B) sites. The sustained expression of VCAM-1 lasts over 24 hours. Primarily, the VCAM-1 protein is an endothelial ligand for VLA-4 (Very Late Antigen-4 or alpha4beta1) of the beta1 subfamily of integrins, and for integrin alpha4beta7. VCAM-1 expression has also been observed in other cell types (e.g., smooth muscle cells). It has also been shown to interact with EZR[2] and Moesin.[2]
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to VCAM-1. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated polyclonal antibody preparation specific for VCAM-1 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 VCAM-1, 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 VCAM-1 in the samples is then determined by comparing the O.D. of the samples to the standard curve