Figure 1. T cell-based immunotherapies share a common requirement for trafficking across vascular checkpoints in tumor tissues.

The direct tumoricidal activity of therapeutic interventions including dendritic cell (DC) vaccination, adoptive T cell transfer, and administration of cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors hinge on the ability of cytotoxic CD8⁺ T cells to traffic across vasculature barriers (blue cells in inset) within the tumor microenvironment.