Factors contributing to the potency of CD8 T cells.

CD8 cytotoxic T lymphocytes (CTLs) play a crucial role in targeting virus-infected and cancer cells. Although other cytotoxic lymphocytes such as CD4 T and natural killer (NK) cells, as well as chimeric antigen receptor (CAR)-T cells, can also identify and destroy aberrant cells, they seem to be significantly less potent based on available experimental data. Here, I contemplate the molecular mechanisms controlling the sensitivity and kinetics of granule-mediated CD8 T cell cytolytic responses. I posit that the clustering of MHC-I molecules and T cell receptors (TCRs) on the cell surface, as well as the contribution of the CD8 co-receptor, are major factors driving exceptionally potent cytolytic responses. I also contend that CD8 T cells with known specificity and engineered TCR-T cells might be among the most efficient cytolytic effectors for treating patients suffering from viral infections or cancer.