Interleukin-1 beta (IL-1β) is a non-secreted proinflammatory cytokine produced mainly by activated macrophages, as well as neutrophils, epithelial cells, and endothelial cells. It possesses metabolic, physiological, haematopoietic activities, and plays one of the central roles in the regulation of the immune responses. Both IL-1α and IL-1β binds to the same receptor and have similar but not identical biological properties. Recombinant porcine interleukin-1 beta is a 17 kDa protein containing 153 amino acid residues and it shares 63 % - 70 % a.a. sequence identity with canine, cotton rat, equine, feline, human, mouse, rat, and rhesus IL1β.