Although IL-1α is cell associated and IL-1β is secreted, they have nearly identical biological activity in that they induce adhesion molecule expression on epithelial cells, control fever induction, and play a role in arthritis and septic shock. Signaling activated by the IL-1R1 promotes these activities through a MYD88 signaling pathway similar to those associated with Toll receptors.

Recombinant human IL-1α produced in E. coli is a non-glycosylated single chain protein containing 159 amino acid residues and having a molecular weight of 18 kDa.