In murine CMV infection, such reactivation events engage TCM CD8 T cells with specificity for certain epitopes that are presented on non-hematopoietic cells and these CD8 T cells respond to this trigger by proliferation, effector memory differentiation and dissemination to peripheral organs where they establish a dynamic but stable pool of TEM cells [13, 15]. Here, CD8A is linked to cytomegalovirus infection.