Figure 11. Model Illustrating the Role of TLR2 and HMGB1 in Initiating T Cell-Dependent Brain Tumor Regression by Flt3L and TK.

Treatment of tumor cells with TK + GCV releases endogenous TLR2 ligands including HMGB1. DC infiltration into tumors and subsequent activation require TLR2 signalling. DC phagocytose tumor antigen and migrate to the dLN where they stimulate T cell clonal expansion resulting in T cell-dependent brain tumor regression and long-term immunological memory.