The receptors for human granulocyte macrophage-colony stimulating factor (GM-CSF), IL-3 and IL-5 are comprised of a cytokine-specific alpha chain, and a common beta chain. The common beta chain on GM-CSF, IL-3, and IL-5 receptors interacts with all three ligands, promoting some degree of overlap between their regulation of hematopoietic cell signaling.
GM-CSF is produced by a number of different cell types, including activated T cells, B cells, macrophages, mast cells, endothelial cells and fibroblasts, in response to cytokine or immune and inflammatory stimuli. IL-3, also known as mast cell growth factor, is a pleiotropic factor produced primarily by activated T cells. IL-3 can stimulate the proliferation and differentiation of pluripotent hematopoietic stem cells, as well as various lineage committed progenitors. IL-5 is a T cell-derived factor that promotes the proliferation, differentiation and activation of eosinophils. In mice, IL-5 is also a growth and differentiation factor for B cells.