Control of Effector CD8 super + T Cell Function by the Transcription Factor Eomesodermin

Activated CD8 super + T cells play a critical role in host defense against viruses, intracellular microbes, and tumors. It is not clear if a key regulatory transcription factor unites the effector functions of CD8 super + T cells. We now show that Eomesodermin (Eomes), a paralogue of T-bet, is induced in effector CD8 super + T cells in vitro and in vivo. Ectopic expression of Eomes was sufficient to invoke attributes of effector CD8 super + T cells, including interferon- gamma (IFN- gamma ), perforin, and granzyme B. Loss-of-function analysis suggests Eomes may also be necessary for full effector differentiation of CD8 super + T cells. We suggest that Eomesodermin is likely to complement the actions of T-bet and act as a key regulatory gene in the development of cell-mediated immunity.