To investigate whether naïve CD8 T cells similarly undergo functional and phenotypic changes over time, we adoptively transferred P14 cells, which are T cell receptor (TCR) transgenic CD8 T cells specific for the lymphocytic choriomeningitis virus (LCMV) GP33 epitope (Pircher et al., 1989), in the absence of infection or cognate antigen stimulation (Fig. 1A). Here, CD8A is linked to infection.