The Human Interleukin 8 (IL-8) CXCL8 ELISA Kit is designed for the quantitative detection and measurement of human IL-8, also known as CXCL8, in cell culture supernatants. IL-8 is secreted by monocytes, macrophages, T cells, neutrophils, fibroblasts, and endothelial cells in response to proinflammatory stimuli such as IL-1 and TNF-α. IL-8 mediates its functions by binding to CXCR1, CXCR2, and DARC receptors, which produce different biological effects. CXCR1 and CXCR2 are G protein-coupled receptors mainly expressed on leukocytes, endothelial cells, epithelial cells, and neuronal cells. The DARC receptor acts as a silent receptor, clearing ELR+ angiogenic chemokines and inhibiting tumor development. The production of IL-8 in biological fluids can be induced by bacteria (e.g. Helicobacter pylori), lipopolysaccharides, viruses (e.g. respiratory syncytial, rhinovirus), and viral products (e.g. X protein of human hepatitis virus B).

The assay is based on a sandwich ELISA method, in which samples are added to ELISA strip plates pre-coated with capture antibodies specific for human IL-8.The captured IL-8 is detected by the addition of a horseradish peroxidase (HRP)-conjugated detection antibody. The addition of the chromogenic enzyme substrate 3,3’5,5’ tetramethylbenzidine (TMB) results in a colored product with an intensity directly proportional to the concentration of human IL-8 in the sample.