IL1a is a non-secreted proinflammatory cytokine produced in a variety of cells including monocytes, tissue macrophages, keratinocytes and other epithelial cells. Both IL1a and IL1beta binds to the same receptor and has similar if not identical biological properties. These cytokines have a broad range of activities including, stimulation of thymocyte proliferation, by inducing IL2 release, B-cell maturation and proliferation, mitogenic FGFlike activity and the ability to stimulate the release of prostaglandin and collagenase from synovial cells. Alternative Names: Leukocyte Endogenous Mediator protein, Lymphocyte-activating factor protein, IL-1 protein, Interleukin 1 alpha protein, MCF protein, Mononuclear Cell Factor protein, IL 1 protein, IL1, IL-1 alpha protein, EP protein, LEM protein, Endogenous Pyrogen protein, Hematopoietin-1 protein, LAF protein, IL-1, IL 1