IL-2 Protein, Rat (HEK293, His)

IL-2, a cytokine primarily produced by activated CD4-positive helper T-cells, and to a lesser extent by activated CD8-positive T-cells and natural killer (NK) cells, plays pivotal roles in immune response and tolerance. It binds to a receptor complex composed of either the high-affinity trimeric IL-2R (IL2RA/CD25, IL2RB/CD122, and IL2RG/CD132) or the low-affinity dimeric IL-2R (IL2RB and IL2RG). The interaction triggers oligomerization and conformational changes in the IL-2R subunits, initiating downstream signaling that begins with the phosphorylation of JAK1 and JAK3. Consequently, JAK1 and JAK3 phosphorylate the receptor, creating a docking site for the phosphorylation of substrates, including STAT5, activating pathways such as STAT, phosphoinositide-3-kinase/PI3K, and mitogen-activated protein kinase/MAPK. IL-2 functions as a T-cell growth factor, enhances NK-cell cytolytic activity, and fosters robust proliferation of activated B-cells, leading to increased immunoglobulin production. Crucially, IL-2 plays a pivotal role in regulating the adaptive immune system by governing the survival and proliferation of regulatory T-cells, crucial for immune tolerance maintenance. Furthermore, it participates in the differentiation and homeostasis of effector T-cell subsets, including Th1, Th2, Th17, as well as memory CD8-positive T-cells.