Tumor-specific CD8+ T cell (TS-CD8+ T cell)

Tumor-specific CD8+ T cells are a specialized subset of cytotoxic T lymphocytes (CTLs) that play a central role in the adaptive immune response against cancer (NIH). These cells recognize specific tumor-associated antigens or neoantigens presented by Major Histocompatibility Complex (MHC) class I molecules on the surface of malignant cells (NIH). Upon activation, they release cytotoxic granules containing perforin and granzymes, which induce apoptosis in the target tumor cells (NIH). In many cancers, these cells become dysfunctional or exhausted due to chronic antigen exposure and the immunosuppressive tumor microenvironment, leading to the upregulation of inhibitory checkpoints such as PD-1 and CTLA-4 (NIH, PubMed). Modern immunotherapies, including checkpoint inhibitors and adoptive cell transfer (e.g., TIL therapy), are designed to either reinvigorate these endogenous cells or provide a large population of ex vivo expanded tumor-reactive cells to achieve clinical regression (NIH, PubMed). Their presence and functional state within the tumor microenvironment are critical determinants of patient prognosis and the efficacy of immunotherapy (Journal of Clinical Investigation).

Other names

Tumor-infiltrating lymphocyteTILCytotoxic T lymphocyteCTLTumor-reactive CD8+ T cellAntigen-specific CD8+ T cell

Immune checkpoint inhibition to restore effector function; Adoptive cell transfer to increase population; Agonistic stimulation of co-stimulatory receptors.