Mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine made by activated T cells, macrophages, vascular endothelial cells and fibroblasts. It has potent stimulatory effects on the growth and differentiation of bone marrow progenitor cells that generate granulocytes, monocytes/macrophages, and megakaryocytes. In peripheral tissues, GM-CSF can act on mature leukocytes to promote inflammatory responses. Mouse GM-CSF runs as a 15.5 - 19 kD band in reducing and non-reducing SDS-PAGE analysis. Mouse GM-CSF protein contains 124 amino acid residues. Recombinat mouse GM-CSF (Cat. No. 554586) is supplied as a frozen liquid comprised of 0.22 um sterile-filtered aqueous buffered solution containing bovine serum albumin, with no preservatives. Recombinant mouse GM-CSF is ≥ 95% pure as determined by SDS-PAGE and an absorbance assay based on the Beers-Lambert law. The endotoxin level is ≤ 0.1 ng per µg of mouse GM-CSF, as measured in chromogenic LAL assay.