Soluble NKG2D ligands: prevalence, release, and functional impact.
Natural Killer (NK) cells are capable to recognize and eliminate malignant cells. Anti-tumor responses of NK cells are promoted by the tumor-associated expression of cell stress-inducible ligands of the activating NK receptor NKG2D. Current evidence suggests that established tumors subvert NKG2D-mediated tumor immunosurveillance by releasing NKG2D ligands (NKG2DL). Release of NKG2DL has been observed in a broad variety of human tumor entities and is thought to interfere with NKG2D-mediated tumor immunity in several ways. Further, levels of soluble NKG2DL (sNKG2DL) were also found to be elevated under various non-malignant conditions, although the functional implications remain largely unclear. Here we review and discuss the available data on the prevalence, release, functional impact, and potential clinical value of sNKG2DL.
Department of Internal Medicine II, Eberhard-Karls-University, Tuebingen, Germany. alexander.steinle@uni-tuebingen.de
Helmut Rainer
HR
Salih
Stefan
S
Holdenrieder
Alexander
A
Steinle
D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D058851:GPI-Linked Proteins; D005786:Gene Expression Regulation; D015395:Histocompatibility Antigens Class I / Q000235:genetics; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000276:immunology; D051379:Mice; D005810:Multigene Family; D009369:Neoplasms / Q000235:genetics / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D014408:Biomarkers, Tumor; D058851:GPI-Linked Proteins; D015395:Histocompatibility Antigens Class I; D036341:Intercellular Signaling Peptides and Proteins; C099187:MHC class I-related chain A; C423230:ULBP2 protein, human