Figure 2: T cell-mediated killing of DCs. Activated T cells express FasL and also secrete cytolytic granules containing perforin and granzyme B. DCs can be killed by activated antigen-specific T cells through Fas- and perforin-dependent mechanisms. Engagement of Fas on DCs by FasL can lead to the activation of caspase-8 and caspase-10 (in humans) and trigger a downstream caspase cascade to induce apoptosis. Cytolytic components secreted by T cells enter DCs through perforin. Granzyme B may directly cleave effector caspases to induce apoptosis. Caspase-independent cell death pathways may also be activated in DCs.