Fig. 1.

Effector T cell-mediated cytotoxic pathways during influenza infection: (1) Granuale excytosis is initiated following TCR stimulus resulting in the release of premade cytotoxic granuales onto target cells. The subsequent release of the pore-forming protein perforin and serine proteases (granzymes) activate caspase cascades resulting in target cell apoptosis. (2) TNF-related proteins are upregulated upon TCR stimulus. Binding to their respective ligands on target cells recruits ligand associated death domains which ultimately activate caspase cascades resulting in target cell apoptosis