TIL from solid tumors can express activation/co-stimulatory molecules like 4-1BB/CD137, a sign of recent antigenic stimulation in the tumor microenvironment (TME). This activated state can be exploited ex vivo to enhance the expansion of tumor-reactive CD8+ TIL for adoptive cell therapy through direct addition of immunomodulators to tumor fragments in culture.
Keywords: 4–1BB; Tumor-Infiltrating Lymphocytes; adoptive T-cell therapy; co-stimulation.