Cytotoxic CD8 T lymphocytes (CTLs) and natural killer (NK) cells are two distinct lineages of immune cells that play important roles in the control of infection and in the detection and removal of cancerous cells. Although the approaches by which CTLs and NK cells kill their target cells and modulate the immune response are quite similar, the mechanisms by which they recognize their targets are distinct. CTLs through their diverse repertoire of clonally rearranged T-cell receptors (TCRs) detect specific peptide–major histocompatibility complex (MHC) class I complexes and are a component of the adaptive immune response. In contrast, NK cells are innate lymphoid cells that use an array of invariant activating and inhibitory receptors to control their activity and specificity. These distinct approaches of target recognition allow for complementary functions, with CTLs being specialized in detecting cancer cells or those infected with intracellular pathogens, such as viruses, whereas a prominent function of NK cells is to eliminate those cells where the pathogen or oncogene has blocked display of MHC class I molecules on the surface of the affected cell. This chapter introduces the biology and functions of the cytotoxic lineages, CTLs, and NK cells in the immune response to infection and malignancy.
|Title of host publication||Clinical Immunology|
|Subtitle of host publication||Principles and Practice|
|Editors||Robert R. Rich, Thomas A. Fleisher, William T. Shearer, Harry W. Schroeder, Anthony J. Frew, Cornelia M. Weyand|
|Place of Publication||Sweden|
|Number of pages||13|
|Publication status||Published - 2019|