Title:Interleukin-21 in Immune and Allergic Diseases
Volume: 11
Issue: 4
Author(s): Massimiliano Sarra, Maria Laura Cupi, Francesco Pallone and Giovanni Monteleone
Affiliation:
Keywords:
IBD, IL-21, IL-21R, cytokine, B cells, epithelial cells, stromal cells, T lymphocytes, dendritic cells (DC)
Abstract: Interleukin-21 (IL-21), a cytokine produced by various subsets of activated CD4+ T cells, plays a major role in
the control of innate and adaptive immune responses. IL-21 biological activity is mediated by binding of the cytokine to a
heterodimeric receptor, composed of a specific subunit, termed IL-21 receptor (IL-21R), and the common γ-chain, that is
shared with IL-2, IL-4, IL-7, IL-9 and IL-15 receptors. IL-21 stimulates the proliferation of CD4+ and CD8+ T
lymphocytes and regulates the profile of cytokines secreted by these cells, drives the differentiation of B cells into
memory cells and Ig-secreting plasma cells, and enhances the activity of natural killer cells. IL-21 controls also the
activity of non-immune cells, such as epithelial cells and stromal cells. The demonstration that IL-21 is involved in the
immune responses occurring in chronic inflammatory and allergic diseases suggests that either disrupting or enhancing
IL-21 signalling may be useful in specific clinical settings.
