Whatever turns you on: accessory-cell-dependent activation of NK cells by pathogens.
Natural killer (NK) cells have a crucial role in combating infections and cancers and their surface receptors can directly recognize and respond to damaged, transformed or non-self cells. Whereas some virus-infected cells are recognized by this same route, NK-cell responses to many pathogens are triggered by a different mechanism. Activation of NK cells by these pathogens requires the presence of accessory cells such as monocytes, macrophages and dendritic cells. Recent studies have identified numerous pathogen-recognition receptors that enable accessory cells to recognize different pathogens and subsequently transmit signals--both soluble and contact-dependent--to NK cells, which respond by upregulating their cytotoxic potential and the production of inflammatory cytokines.
Newman
Kirsty C
KC
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
Riley
Eleanor M
EM
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D001424:Bacterial Infections / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D020239:Receptor Cross-Talk / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology*; D014777:Virus Diseases / Q000276:immunology