Interleukin-1 beta (IL-1β)

Interleukin-1 beta is a cytokine released by immune cells that drives fever, inflammation and pain signaling in response to infection or tissue damage.

It is produced as an inactive precursor inside macrophages and other cells and is cut into its active form by an enzyme complex assembled by the NLRP3 inflammasome. Once released, IL-1β binds receptors on nearby cells, activates NF-kB signaling, and prompts the production of further cytokines including IL-6 and TNF-α, amplifying the inflammatory response. It also sensitizes nociceptors, which is one reason inflamed tissue hurts, and it acts on the brain to produce fever, fatigue and sickness behavior.

Elevated IL-1β is a feature of rheumatoid arthritis, osteoarthritis, inflammatory bowel disease, periodontitis and several autoinflammatory syndromes, and biologic drugs that block it are used in some of these. In cannabinoid research, IL-1β is a common laboratory readout: cell and animal studies report changes in its production after cannabidiol and other cannabinoids. Those findings are preclinical and have not been confirmed as clinical benefit in people.