Effect of NKG2D ligand expression on host immune responses.
Natural killer group 2, member D (NKG2D) is an activating receptor present on the surface of natural killer (NK) cells, some NKT cells, CD8(+) cytotoxic T cells, gammadelta T cells, and under certain conditions CD4(+) T cells. Present in both humans and mice, this highly conserved receptor binds to a surprisingly diverse family of ligands that are distant relatives of major histocompatibility complex class I molecules. There is increasing evidence that ligand expression can result in both immune activation (tumor clearance, viral immunity, autoimmunity, and transplantation) and immune silencing (tumor evasion). In this review, we describe this family of NKG2D ligands and the various mechanisms that control their expression in stressed and normal cells. We also discuss the host response to both membrane-bound and secreted NKG2D ligands and summarize the models proposed to explain the consequences of this differential expression.
Department of Microbiology and Immunology, The Biomedical Sciences Graduate Program and The Cancer Research Institute, University of California San Francisco, San Francisco, CA 94143, USA.
Marine
M
Champsaur
Lewis L
LL
Lanier
D000818:Animals; D015551:Autoimmunity; D003602:Cytotoxicity, Immunologic; D058851:GPI-Linked Proteins; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology* / Q000821:virology; D008024:Ligands; D051379:Mice; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000276:immunology*; D009369:Neoplasms / Q000276:immunology; D015398:Signal Transduction; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000821:virology; D019139:Tumor Escape; D014780:Viruses / Q000276:immunology / Q000472:pathogenicity
D058851:GPI-Linked Proteins; D015395:Histocompatibility Antigens Class I; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D055655:NK Cell Lectin-Like Receptor Subfamily K; C423230:ULBP2 protein, human