The Human GM-CSF ELISA Kit is designed for the quantitative detection and measurement of granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as CSF2, in cell culture supernatants. GM-CSF is secreted by activated T cells, B cells, macrophages, monocytes, endothelial cells, and fibroblasts in response to proinflammatory stimuli. The GM-CSF receptor, CSF2R, is composed of one α-chain and β-chain. The β-chain is shared with interleukin 3 (IL-3) and 5 (IL-5) receptors with low and high affinity binding to GM-CSF. The active form of GM-CSF exists as a homodimer and the encoding gene has been localized to a cluster of genes at chromosome region 5q31, which is known for 5q minus (5q-) syndrome and myelogenous leukemia. The overexpression of GM-CSF may be a critical indicator for inflammatory and autoimmune diseases such as arthritis, nephritis, and psoriasis.

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 GM-CSF. The captured GM-CSF 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 GM-CSF in the sample.