Abstract
Natural killer (NK) cells have potent capacities to immediately kill cellular targets and produce cytokines that may potentially damage normal self-tissues unless they are kept in check. Such tolerance mechanisms are incompletely understood. Here we discuss recent studies suggesting that NK cells undergo a host major histocompatibility complex (MHC) class I-dependent functional maturation process, termed 'licensing'. Ironically, licensing directly involves inhibitory receptors that recognize target cell MHC class I molecules and block activation of NK cells in effector responses. This process results in two types of tolerant NK cells: functionally competent (licensed) NK cells, whose effector responses are inhibited by self-MHC class I molecules through the same receptors that conferred licensing, and functionally incompetent (unlicensed) NK cells.
Original language | English (US) |
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Pages (from-to) | 143-154 |
Number of pages | 12 |
Journal | Immunological Reviews |
Volume | 214 |
Issue number | 1 |
DOIs | |
State | Published - Dec 2006 |
Externally published | Yes |
Keywords
- Licensing
- Major histocompatibility complex
- Natural killer cells
- Tolerance
ASJC Scopus subject areas
- Immunology