# Cytokines --- **Cytokines** are the [[signaling molecule|signaling molecules]] of the [[immune system]]. Cytokines have a broad range of roles, and can be roughly divided into 5 different classes: chemokines, colony-stimulating factors, interferons, tumor necrosis factors and interleukins. - **Chemokines** are a class of cytokines that cause [[chemotaxis]] to occur, summoning [[white blood cells]] to the area. - **Colony-stimulating factors** (or CSFs) are a class of cytokines that induce [[cell division]] of [[white blood cells]]. Once they've divided this way, they can differentiate into different types of WBCs. - [[Interferons]] (or INFs) are a class of cytokine that interfere with [[animal virus|viral]] replication, and play a large role in slowing viral infections. - **Tumor necrosis factors** (or TNFs) are a class of cytokine that can do a lot of different things such as killing tumors, triggering apoptosis, or triggering [[inflammation]]. - **Interleukins** are a class of cytokine that can do a lot of different things like cause [[fever]] or [[inflammation]]. ___