BioVision’s Human Apolipoprotein E (ApoE) Enzyme-Linked Immunosorbent Assay (ELISA) Kit is an in vitro assay for the quantitative measurement of human ApoE. ApoE transports lipoproteins, fat-soluble vitamins, and cholesterol via the lymph system to the blood. It is synthesized mainly in liver, while it has also been identified in the brain, kidneys, and spleen. In the nervous system, ApoE is synthesized in non-neuronal cell types, most notably astroglia and microglia, while neurons preferentially express its receptors. Defects in ApoE lead to familial dysbetalipoproteinemia (increased plasma cholesterol and triglycerides). More recently, ApoE has been implicated in several biological processes not directly related to lipoprotein transport, including Alzheimer's disease, immunoregulation, and cognition. The assay employs an antibody specific for human ApoE coated on a 96-well plate. Standard and samples are pipetted into wells and ApoE present in the sample is bound to the wells by immobilized antibody. Wells are washed and human ApoE specific detection antibody is added. After washing away unbound detection antibody, HRP-conjugate is pipetted to the wells. The wells are again washed, a TMB substrate solution is added to the wells, and color develops in proportion to the amount of bound ApoE. Stop Solution changes the color from blue to yellow, and the intensity of the color is measured at 450 nm. This ELISA kit recognizes ApoE-2, ApoE-3, and ApoE-4 isoforms. Sensitivity of the kit is 25 ng/ml and detection range is from 25 ng to 1.6