Different checkpoints in human NK-cell activation.
After the discovery, in humans and mice, of inhibitory natural killer (NK) receptors specific for MHC class I molecules, the mechanism by which NK cells kill tumor or virus-infected cells was thought to be clarified: NK cells would kill those target cells that have lost, or underexpress, MHC class I molecules. However, a more complex scenario has recently emerged. For example, certain NK cells express insufficient amounts of triggering receptors, and target cells can lack ligands for such receptors. Thus, it appears that the activation of NK cells and their potentially harmful effector functions are under the control of different checkpoints.
Moretta
Lorenzo
L
Istituto Giannina Gaslini, Largo Gerolamo Gaslini 5, 16147 Genova-Quarto, Italy. lorenzomoretta@ospedale-gaslini.ge.it
Bottino
Cristina
C
Pende
Daniela
D
Vitale
Massimo
M
Mingari
Maria Cristina
MC
Moretta
Alessandro
A
D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D008024:Ligands; D051379:Mice; D018448:Models, Immunological; D011971:Receptors, Immunologic / Q000378:metabolism; D054340:Receptors, KIR
D015395:Histocompatibility Antigens Class I; D008024:Ligands; D011971:Receptors, Immunologic; D054340:Receptors, KIR