Transforming growth factor-β:: an important cytokine in the mucosal immune response

Cytokines are important mediators in the intestine regulating both oral tolerance and mucosal inflammation. Central to this immune-regulatory role is the cytokine transforming growth factor-beta (TGF-beta). Oral tolerance and inflammatory responses in the gut are regulated through the balance of the Th1, Th2, and Th3 lymphocyte responses-a balance influenced strongly by TGF-beta. TGF-beta also modulates B-cell responses by increasing the production of immunoglobulin A (IgA) while decreasing the production of IgG, IgM, and ISE. In intestinal epithelial cells, TGF-beta activates signal transduction pathways resulting in the inhibition of proliferation and tumorigenesis. Currently, these signaling pathways are being dissected at the molecular level. (C) 2000 Lippincott Williams & Wilkins, Inc.