title: The double life of NK receptors: stimulation or co-stimulation?
abstract: Stimulatory killer immunoglobulin-like receptors, NKG2D and stimulatory receptors of the CD94-NKG2 family have duplicity in function. On natural killer (NK) cells, these receptors act as independent and competent recognition units. Stimulatory NK receptors also appear on subsets of effector T cells, particularly those that have replicated extensively. When expressed on T cells, they amplify signals mediated through the T-cell antigen receptor and, thus, function as co-stimulatory, but not direct stimulatory, molecules. One mechanism responsible for this dichotomy is the differential expression of adaptor molecules. This duplicity in function, which is not seen for other co-stimulatory molecules, is responsible for the unique context information provided by the NK receptors, and it could explain their involvement in chronic inflammation and autoimmunity.
authors.affiliation: Department of Immunology, 401 Guggenheim, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Snyder
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Weyand
authors.forename: Jörg J
authors.initials: JJ
authors.lastname: Goronzy
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D037181:Lectins, C-Type / Q000276:immunology*; D008213:Lymphocyte Activation; D055654:NK Cell Lectin-Like Receptor Subfamily C; D051920:NK Cell Lectin-Like Receptor Subfamily D; D055655:NK Cell Lectin-Like Receptor Subfamily K; D011971:Receptors, Immunologic / Q000276:immunology*; D055607:Receptors, Natural Killer Cell; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015703:Antigens, CD; C527054:KLRC1 protein, human; C497869:KLRD1 protein, human; C527085:KLRK1 protein, human; D037181:Lectins, C-Type; D055654:NK Cell Lectin-Like Receptor Subfamily C; D051920:NK Cell Lectin-Like Receptor Subfamily D; D055655:NK Cell Lectin-Like Receptor Subfamily K; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell