Figure 1.

Anti-tumor cytotoxicity pathways. Tumor-specific cytotoxic T lymphocytes (CTLs) recognize tumor cells through TCR and Ag-bound MHC class I. Interactions between the CTL and the tumor cell involve direct cell-cell physical contact and release of modulator molecules (i.e. IFN-γ and other molecules). CTLs primarily use the perforin exocytosis pathway and the Fas-mediated apoptosis pathways to destruct the tumor cells. However, other effector mechanisms, such as the LTβR-mediated apoptosis pathway, also play a role in tumor cell destruction.