Figure 2. Lung T cell-mediated recall responses involve in situ expansion and enhanced migration from lung-associated lymph nodes.

During a recall response, lung T cells rapidly expand in number in response to respiratory virus, which is due to in situ proliferation of T_RM as well as the rapid ingress of peripheral T cells that are rapidly activated in the local draining lymph node due to increased numbers of lymph node dendritic cells, leading to enhanced effector T cell generation and migration to the lung.