natural killer cell

Syllable breakdown

Dictionary meaning

a type of cytotoxic lymphocyte of the innate immune system that can recognise and destroy virally infected cells, tumour cells, and cells under physiological stress without prior sensitisation or the need for antigen presentation via MHC molecules; natural killer cells act rapidly as a first line of defence, using activating and inhibitory receptors to distinguish healthy self cells from abnormal targets, and killing target cells through the release of cytotoxic granules containing perforin and granzymes or through death-receptor signalling pathways; they also produce cytokines including interferon-gamma that help coordinate broader immune responses