Dendritic cells (DCs) take up and process exogenous particulate or cell-associated antigens such as microbes or tumor cells for MHC-I cross-presentation. Particulate antigens have been reported to be more efficiently cross-presented than soluble antigens by DCs (Khor et al. 2008). Particulate antigens are internalized by phagosomes. There are two established models that explain the mechanism by which exogenous particulate antigens are presented through MHC I; the cytosolic pathway where internalized antigens are somehow translocated from phagosomes into cytosol for proteasomal degradation and the vacuolar pathway (Lin et al. 2008, Amigorena et al. 2010).