Cytokines, their Receptors and Signals

Cytokines are intercellular protein signals and multifunctional mediators of inflammation and tissue repair. Cytokines by interacting with receptors activate a wide variety of cell types and initiate signal transduction cascades resulting in the transcription of multiple genes involved in both innate and adaptive immunity. Many of the cytokines augment inflammatory reactions in the course of host defense, while others engage in restoring homeostasis and suppress inflammation. Various cytokines have been shown to exacerbate or suppress autoimmune diseases. This chapter therefore reviews the members of the cytokine and receptor subfamilies that can exacerbate or diminish inappropriate autoimmune reactions aimed at “self” antigens. Consequently, targeting some of these proinflammatory or suppressive cytokines, their receptors, or signal transduction pathways, although not curative, can be of considerable therapeutic benefit by reducing autoimmune reactions.