Il21

A novel cytokine related to IL2 and IL15 was recently identified and designated IL21. IL21 has been found to be a powerful growth factor for naive B cells. The receptor for IL21 (IL21R, also termed NILR for novel Interleukin receptor) is a new member of the class I cytokine receptor family. IL21R forms a complex with the common cytokine receptor g chain, gc, and mediates IL21 signaling. Both IL21R and the gc are necessary for the IL21 function. IL21 and its receptor activate JAKSTAT signaling pathway. IL21R is expressed in spleen, thymus, natural killer (NK), T and B cell lines. IL21 plays a role in the proliferation and maturation of NK, B and T cell populations.