The family of IL-1 cytokines (IL-1F) encompasses eleven proteins that share similar structure and signaling mode (similar receptors, similar signaling pathways) (Dinarello 2013). IL-1F cytokines are involved in initiation as well as regulation of inflammation and are central players of innate immunity.
Studies started in the 1940s with the first identification of factors able to induce fever (pyrexin, endogenous pyrogen, leukocytic pyrogen) and developed until the cloning of the first cytokines of the family (IL-1α and IL-1β) in the 1980s. After that, studies bloomed and at present eleven members of the family have been identified, and the function of several of them clarified.
Several IL-1F cytokines are synthesized as long precursors, of which the C-terminal domain is the active secreted cytokine. Secretion takes place by nonconventional mechanisms that are still partly unknown.
In many cases, the procytokine forms have an...