IL-2 (interleukin 2) is a powerful immunoregulatory lymphokine produced by T-cells in response to antigenic or mitogenic stimulation. It is a type I cytokine. IL-2/IL-2R (interleukin 2/IL-2 receptor) signaling is required for T-cell proliferation and other fundamental functions which are essential for the immune response. IL-2 stimulates growth and differentiation of B-cells, NK (natural killer) cells, lymphokine activated killer cells, monocytes, macrophages and oligodendrocytes. It is associated with recurrent oral ulcer, asthma and Mycoplasma pneumoniae infection in children. Absence of IL2 in mice causes fatal lymphoproliferative inflammatory disease (IL-2 deficiency syndrome). IL-2 signaling involves three pathways: phosphoinositol 3-kinase (PI3-K)/AKT, Ras-MAPK (mitogen activated protein kinase), and JAK-ST at (Janus kinase - signal transducers and activators of transcription) pathways.
