title: Ligand dimensions are important in controlling NK-cell responses.
abstract: Size-dependent protein segregation at the cell-cell contact interface has been suggested to be critical for regulation of lymphocyte function. We investigated the role of ligand dimensions in regulation of mouse NK-cell activation and inhibition. Elongated forms of H60a, a mouse NKG2D ligand, were generated and expressed stably in the RMA cell line. RMA cells expressing the normal size H60a were lysed efficiently by both freshly isolated and IL-2 stimulated C57BL/6 mouse-derived NK cells; however the level of lysis decreased as the H60a ligand size increased. Importantly, H60a elongation did not affect NKG2D binding, as determined by soluble NKG2D tetramer staining, and by examining NK-cell target cell conjugate formation. CHO cells are efficient at activating NK cells from C57BL/6 mice, and expression of a single chain form of H-2K(b), a ligand for the mouse inhibitory receptor Ly49C, strongly inhibited such activation of Ly49C/I positive NK cells. Elongation of H-2K(b) resulted in decreased inhibition of both lysis and IFN-gamma production by NK cells. These results establish that small ligand dimensions are important for both NK-cell activation and inhibition, and suggest that there are shared features between the mechanisms of receptor triggering on different types of lymphocytes.
authors.affiliation: Department of Immunology, Wright-Fleming Institute, Imperial College London, London, UK.
authors.forename: Joanna
authors.initials: J
authors.lastname: Brzostek
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Chai
authors.forename: Friedemann
authors.initials: F
authors.lastname: Gebhardt
authors.forename: Dirk H
authors.initials: DH
authors.lastname: Busch
authors.forename: Rui
authors.initials: R
authors.lastname: Zhao
authors.forename: P Anton
authors.initials: PA
authors.lastname: van der Merwe
authors.forename: Keith G
authors.initials: KG
authors.lastname: Gould
mesh_terms: D000818:Animals; D016466:CHO Cells; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D006183:H-2 Antigens / Q000235:genetics / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D008024:Ligands; D051379:Mice; D008810:Mice, Inbred C57BL; D015778:Minor Histocompatibility Antigens / Q000235:genetics / Q000378:metabolism*; D016254:Mutagenesis, Insertional / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D055650:NK Cell Lectin-Like Receptor Subfamily A / Q000235:genetics / Q000378:metabolism*; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D019076:Transgenes / Q000235:genetics
chemical_list: D006183:H-2 Antigens; C032876:H-2Kb protein, mouse; C527086:Klrk1 protein, mouse; D008024:Ligands; D015778:Minor Histocompatibility Antigens; D055650:NK Cell Lectin-Like Receptor Subfamily A; D055655:NK Cell Lectin-Like Receptor Subfamily K; C114735:minor H antigen H60