Mouse granulocyte/macrophage-colony stimulating factor (GM-CSF) is a 14 kDa protein that is believed to contain 124 amino acid residues based on its cDNA sequence. Evidence from several laboratories demonstrates that it is primarily produced by activated T cells and macrophages in mice. It is also produced by other cell types including endothelium and fibroblasts when stimulated by TNF, IL-1, IL-2, and IFN-γ. GM-CSF stimulates growth of macrophages, granulocytes, and dendritic cells and it plays a pivotal role in the immune response in mice. There are membrane-bound and soluble forms of GM-CSF. Soluble GM-CSF is found in a complex associated with the extracellular matrix. Both forms function in the biological processes mentioned above. Recombinant GM-CSF synthesized in E. coli is nonglycosylated and is also biologically active. The Mouse GM-CSF ELISA Test Kit is designed for quantitative determination of the concentration of mouse GM-CSF in serum, plasma, and cell culture supernatant.