Tumor cell lysis by natural killer cell activity (None)

Tumor cell lysis by natural killer (NK) cell activity refers to the process by which NK cells, a component of the innate immune system, recognize and destroy tumor cells. This cytotoxic function is central to immune surveillance against cancer and is regulated through a complex interplay of activating and inhibitory signals. NK cells are capable of killing tumor cells without prior sensitization or priming. The lytic process involves direct recognition of stressed or abnormal cells (such as tumor or virus-infected cells), followed by targeted destruction while sparing healthy self-cells. Mechanisms include Perforin/Granzyme Pathway, Death Receptor Pathway, and Antibody-Dependent Cellular Cytotoxicity (ADCC). Key receptors include Natural Cytotoxicity Receptors (NCRs): NKp46, NKp30, and NKp44; NKG2D; CD16a/FcγRIIIa. Inhibitory receptors recognize MHC class I molecules. Regulation is determined by the balance between activating/inhibitory receptor signals. Therapeutic implications include the use of cytokines (IL-2/IL-15) for activation, monoclonal antibodies that enhance ADCC, and checkpoint inhibitors targeting PD-(L)1 axis. Recent advances include engineered molecules like bispecific engagers.

Perforin/granzyme exocytosis; death receptor ligand expression; ADCC; cytokine activation; checkpoint blockade