Watzl, Carsten

AbstractNatural killer (NK) cells are a subpopulation of lymphocytes that can mediate cytotoxicity of certain tumor cells, virus‐infected cells, and normal cells. In addition to their cytotoxic potential, NK cells secrete a variety of cytokines and chemokines that can modulate the function, growth, and differentiation of other immune cells. These different responses are initiated by the interaction of specific NK surface receptors with defined soluble or cell‐associated ligands. There are several different types of receptors on the NK cell surface including “triggering” receptors, adhesion molecules, cytokine receptors, and MHC‐recognizing killer‐cell inhibitory receptors. The functional response of an NK cell is the result of the integration of signals transduced by these different types of receptors. Some of these signaling pathways are similar to other lymphoid cells, but there are also unique features employed by NK cells. This overview focuses on receptor‐initiated signaling pathways that modulate NK functions.