At day 6 after infection/vaccination, equal numbers of NP-tetramer+ cells were present in the lung-draining mediastinal lymph node (mLN) of both cohorts (Fig. 1B); however, assessment of the expression of a panel of T cell activation markers revealed that NP-tetramer+ CD8+ T cells in the mLN of S-FLU–immunized mice expressed reduced levels of CD25 and Killer cell lectin-like receptor subfamily G member 1 (KLRG1) but equivalent levels of CD62L compared to NP-tetramer+ CD8+ T cells activated following PR8 infection (Fig. 1C). The gene discussed is KLRG1; the disease is infection.