title: Acquisition of external major histocompatibility complex class I molecules by natural killer cells expressing inhibitory Ly49 receptors.
abstract: Murine natural killer (NK) cells express inhibitory Ly49 receptors specific for major histocompatibility complex (MHC) class I molecules. We report that during interactions with cells in the environment, NK cells acquired MHC class I ligands from surrounding cells in a Ly49-specific fashion and displayed them at the cell surface. Ligand acquisition sometimes reached 20% of the MHC class I expression on surrounding cells, involved transfer of the entire MHC class I protein to the NK cell, and was independent of whether or not the NK cell expressed the MHC class I ligand itself. We also present indirect evidence for spontaneous MHC class I acquisition in vivo, as well as describe an in vitro coculture system with transfected cells in which the same phenomenon occurred. Functional studies in the latter model showed that uptake of H-2D(d) by Ly49A+ NK cells was accompanied by a partial inactivation of cytotoxic activity in the NK cell, as tested against H-2D(d)-negative target cells. In addition, ligand acquisition did not abrogate the ability of Ly49A+ NK cells to receive inhibitory signals from external H-2D(d) molecules. This study is the first to describe ligand acquisition by NK cells, which parallels recently described phenomena in T and B cells.
authors.affiliation: Microbiology and Tumor Biology Center, Karolinska Institutet, S-171 77 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Sjöström
authors.forename: M
authors.initials: M
authors.lastname: Eriksson
authors.forename: C
authors.initials: C
authors.lastname: Cerboni
authors.forename: M H
authors.initials: MH
authors.lastname: Johansson
authors.forename: C L
authors.initials: CL
authors.lastname: Sentman
authors.forename: K
authors.initials: K
authors.lastname: Kärre
authors.forename: P
authors.initials: P
authors.lastname: Höglund
mesh_terms: D000818:Animals; D000950:Antigens, Ly; D002352:Carrier Proteins / Q000378:metabolism*; D003602:Cytotoxicity, Immunologic; D006183:H-2 Antigens / Q000378:metabolism; D064532:Histocompatibility Antigen H-2D; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism*; D037181:Lectins, C-Type; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D055650:NK Cell Lectin-Like Receptor Subfamily A; D051381:Rats; D055630:Receptors, NK Cell Lectin-Like; D014407:Tumor Cells, Cultured
chemical_list: D000950:Antigens, Ly; D002352:Carrier Proteins; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; D015395:Histocompatibility Antigens Class I; C527088:Klra1 protein, mouse; D037181:Lectins, C-Type; D008565:Membrane Proteins; D055650:NK Cell Lectin-Like Receptor Subfamily A; D055630:Receptors, NK Cell Lectin-Like