Fig. 1.

Overview of the primary CD4 T cell response and memory generation following Influenza infection. (a) Following Influenza infection, naïve DCs in the lung take up virus and virally-derived particles, driving their maturation and migration to the lung-draining lymph node. (b) Mature, activated DCs activate Influenza-specific naïve CD4 T cells trafficking through the lymph nodes. (c) CD4 effector cells traffic to the lung and can also reach the spleen via the circulation. (d) Effectors in the lung secrete effector cytokines and directly lyse virally-infected epithelial cells. (e) CD4 effectors also activate B cells and CD8 T cells in lymphoid tissues, allowing them to assume effector functions. (f) Responding effectors are retained as long live memory populations at diverse sites