To image T cell priming and effector responses to influenza in the lung, mouse-adapted H1N1 influenza virus expressing the LCMV protein GP33 (A/WSN/33; FLU-LCM) was used to infect CD11c-eYFP mice 24 h after the adoptive transfer of 5×104 naïve GP33-specific eGFP+CD8+ (P14) T cells [18] (Figure 2A). The gene discussed is CD8A; the disease is influenza.