After i.n. infection with the A/JAPAN virus the onset of CD8+ T cell proliferation in the DLN occurs between 54 hrs and 60 hrs p.i. This reflects the fact that this influenza virus strain reaches high steady state viral titers in the mouse respiratory tract more rapidly than the A/PR/8 virus and therefore triggers respiratory dendritic cell (RDC) migration to the DLN to initiates T cell activation more rapidly [21]. Here, CD8A is linked to infection.