Unité des Cytokines et Développement Lymphoïde, Institut Pasteur, 25 rue du Dr Roux, 75742, Paris, France. vosshenr@pasteur.fr
The discovery of the cytokine IL-21 adds another member to the ever-growing list of small secreted molecules that have potent effects on lymphoid cells. Initial characterization of the IL-21 receptor complex suggests that IL-21 may belong to the cytokine family whose receptors share the common gamma chain, gamma(c).