IL-21-Cre mice express a codon optimized Cre recombinase (iCre) under control of the mouse interleukin 21 (Il21) promoter. IL-21 is a cytokine produced by CD4+ T cell populations, in particular T follicular helper (TFH) cells, TH17 cells, and natural killer T (NKT) cells. IL-21 exerts numerous immune-enhancing and immune-regulatory functions, thus playing a critical role in the initiation and control of both innate and adaptive immune responses. It acts on a broad range of cell types including, but not limited to, T cells, B cells, macrophages, monocytes, and dendritic cells by modulating proliferation, differentiation, phagocytosis, apoptosis, and the production of other cytokines. IL-21-Cre mice mice may be particularly useful for the generation of reporter mice that allow for the characterization and tracing of the development of IL-21 expressing cells such as follicular T helper (Tfh) cells. Hemizygous mice are viable and fertile. The donating investigator did not attempt to make a homozygous colony.
