Cytokines and Growth Factors

Cytokines are a large group of low molecular weight proteins, polypeptides or glycoproteins that are secreted by various immune cells including macrophages, lymphocytes and mast cells, as well as other cell types such as endothelial cells. They play important roles in regulating cell growth, differentiation, and activation, and are involved in many aspects of both innate and adaptive immune responses. Cytokines include interleukins, chemokines, interferons and other signalling molecules[1][2][3].
Growth factors are soluble signaling molecules capable of stimulating a variety of cellular processes including cell proliferation, migration, differentiation and multicellular morphogenesis during development and tissue healing. Usually, Growth factors are secreted proteins or steroid hormones[4][5].
The term “Growth factor” and “Cytokine” are often used interchangeably. Some growth factors are small peptides called cytokines. The cytokines affecting cell growth/differentiation signaling pathways are considered growth factors, such as GM-CSF[5][6].