anti-Interleukin 4 (human), mAb (3)

Interleukin-4 (IL-4) is a monomeric TH2 cytokine of approximately 17 kDa that shows pleiotropic effects during immune responses. It functions as a potent regulator of immunity. IL-4 was first identified as a T cell-derived growth factor for B cells. IL-4 and IL-13 activate many common signaling pathways. IL-4 is mainly produced by Th2 cells, but can also be secreted by natural killer T (NKT) cells, mast cells, eosinophils, basophils, and innate-type lymphoid cells. IL-4 can signal through the type II IL-4 receptor, which is a heterodimer of IL-4Rα and IL-13Rα1 chains, and also through the type I IL-4 receptor, which is a heterodimer of IL-4 receptor alpha (IL-4Rα) and common γ(γc) chains. IL-4 binding results in tyrosine kinase Janus kinase 1 (JAK1) and JAK3 activation. IL-4 functions as a co-mitogen of B-cells. It is important in leukocyte survival, Th2 cell-mediated immunity, IgE class switching in B cells, and tissue repair and homeostasis through 'alternative' macrophage activation.