A Kit ligand, also known as stem cell factor (SCF), is a protein that plays a crucial role in the development and function of blood cells. It binds to the Kit receptor, which is found on the surface of certain cells, including hematopoietic stem cells. This interaction is essential for the survival, proliferation, and differentiation of these cells into various types of blood cells. In addition to its role in hematopoiesis, Kit ligand is also involved in other biological processes, such as pigmentation and the immune response. It is produced by various cell types, including fibroblasts and endothelial cells, and is important for the maintenance of mast cells, which are key players in allergic reactions and immune responses.