WT and Plac8-/- mice were infected with 104 X31, and NP-reactive CD8 T cells were examined in the bronchoalveolar lavage fluid (BAL) as well as in lung, spleen and lung-draining mediastinal lymph node (mdLN) tissues at the peak of the effector (10 days post infection, dpi) and memory (35 dpi) CD8 T cell response (Fig 4A & 4C). The gene discussed is CD8A; the disease is infection.