Interleukin 4

Abstract

Human interleukin 4 (IL-4), a mature 129 amino acid (AA) glycoprotein secreted by activated T cells and basophils, is a pleiotropic cytokine that affects T and B lymphocytes, monocytes, dendritic cells, polymorphonuclear cells, fibroblasts, endothelial cells and hepatocytes. It may display contrasting biological effects according to the differentiation stage of a given cell and to the cytokine environment. IL-4 is a growth factor for activated T and B cells, and both in vivo and in vitro studies have shown the crucial role of IL-4 in the induction of immunoglobulin E production. IL-4's ability in inducing naive T helper cells to differentiate into IL-4 secreting Th2 cells is critical. IL-4 inhibits, in vitro and in vivo, the secretion of proinflammatory cytokines by monocytes/macrophages and polymorphonuclears. Human IL-4 binds to a high affinity receptor which is composed of at least a 130-kD glycoprotein of 800 AA and a γ chain common to the IL-2, IL-7 and IL-13 receptors. IL-4 may prove useful as an antitumoural and anti-inflammatory agent.