Description
IL-1α is distinct from the other agonist member of the IL-1 family, IL-1β. Although IL-1α triggers the same IL-1 receptor and although many of the biological effects of IL-1α are similar to those of IL-1α, in humans IL-1α is predominantly an intracellular molecule. In fact, there is evidence that IL-1α has both intracellular functions as a precursor molecule due to a nuclear localization sequence. IL-1α as an unprocessed precursor is biologically as active as the processed form. IL-1α is also found constitutively in epithelial cells, whereas constitutive expression of IL-1β is rare. In many ways, IL-1α appears to be closer to the fibroblast growth factor family than the secreted IL-1β form. Therapeutic stratiegies for blocking IL-1β predominate over those for blocking IL-1α. Many humans have circulating neutralizing antibodies to IL-1α but not IL-1β