Tumor-infiltrating T lymphocyte (TIL)

Tumor-infiltrating T cells (TILs) are a specialized population of T lymphocytes that have migrated from the systemic circulation into the tumor microenvironment to identify and eliminate malignant cells (National Cancer Institute, 2023). These cells are capable of recognizing a broad array of patient-specific tumor neoantigens through their endogenous T-cell receptors (TCRs), making them a potent tool for personalized immunotherapy. In clinical practice, TILs are harvested from a patient's resected tumor, expanded to billions of cells ex vivo using growth factors like Interleukin-2 (IL-2), and then re-infused into the patient following lymphodepleting chemotherapy (Rosenberg & Restifo, 2015, Science). This therapeutic approach was recently validated by the 2024 FDA approval of Lifileucel (Amtagvi) for the treatment of advanced melanoma, marking the first approved cellular therapy for a solid tumor (FDA, 2024). While highly effective in inducing durable responses in some patients, the success of TIL therapy is often challenged by the immunosuppressive nature of the tumor microenvironment and the requirement for high-dose IL-2, which can cause significant systemic toxicities such as capillary leak syndrome (StatPearls, 2023).

Other names

Tumor-infiltrating lymphocytesTILsTumor-associated lymphocytesAutologous tumor-infiltrating lymphocytesCD3+ tumor-infiltrating lymphocytes

Adoptive cell transfer involving the ex vivo isolation of autologous T cells from a patient's tumor, followed by large-scale expansion using Interleukin-2 and re-infusion to mediate direct, polyclonal tumor cell lysis via T-cell receptor (TCR) recognition of tumor neoantigens.