Goat Anti-Feline IL2 polyclonal antibody for ELISA(Cap), ICC/IF, WB. Interleukin-2 (IL-2) is a secreted, single chain alpha-helical polypeptide that has potent stimulatory activity for antigen-activated T cells. The feline IL-2 gene encodes a 154 amino acid (aa) precursor protein with a 20 aa signal peptide plus a 134 aa mature segment. There are suggestions that the mature protein may beO-glycosylated. At the aa sequence level, mature feline IL-2 is 78%, 82%, 60%, 64%, 62%, 75%, 62%, and 76% identical to mature human, canine, mouse, rat, cotton rat, porcine, goat, and equine IL-2, respectively. Mammalian cells known to express IL-2 include CD4+ and CD8+ T cells, visceral smooth muscle cells, eosinophils, gamma d T cells, B cells and dendritic cells. The biological activity of IL-2 is mediated by IL-2 receptor complexes consisting of three distinct subunits (alpha, beta, gamma) in two combinations. The high-affinity signaling IL-2 receptor complex is a heterotrimer of the IL-2 receptor alpha, beta, gamma subunits. The intermediate signaling complex is a heterodimer of the IL-2 R beta b and gamma subunits. The non-ligand binding gamma subunit, referred to as the commongamma subunit (gamma c), is also a subunit of the receptor complexes of IL-4, IL-7, IL-9 and IL-15. Functionally, IL-2 is best known for its autocrine and paracrine activity on T cells. On naïve CD8+ T cells, high IL-2 levels can induce cell proliferation with a bias towards cytotoxicity. In the presence of low levels of IL-2, CD8+ T cells preferentially undergo apoptosis with a bias towards cytokine secretion. IL-2 also seems to play a central role in the expansion and maintenance of CD4+ CD25+ regulatory T cells. This indicates IL-2 may be a key cytokine in the natural suppression of autoimmunity.