Bone marrow allograft rejection mediated by a novel murine NK receptor, NKG2I

J Exp Med. 2004 Jan 5;199(1):137-44. doi: 10.1084/jem.20030851.


Natural killer (NK) cells mediate bone marrow allograft rejection. However, the molecular mechanisms underlying such a rejection remain elusive. In previous analyses, it has been shown that NK cells recognize allogeneic target cells through Ly-49s and CD94/NKG2 heterodimers. Here, we describe identification and characterization of a novel murine NK receptor, NKG2I, belonging to the NKG2 family. NKG2I, which was composed of 226 amino acids, showed approximately 40% homology to the murine NKG2D and CD94 in the C-type lectin domain. Flow cytometric analysis with anti-NKG2I monoclonal antibody (mAb) revealed that expression of NKG2I was largely confined to NK and NKT cells, but was not seen in T cells. Furthermore, anti-NKG2I mAb inhibited NK cell-mediated cytotoxicity, whereas cross-linking of NKG2I enhanced interleukin 2- and interleukin 12-dependent interferon-gamma production. Similarly, the injection of anti-NKG2I mAb before the allogeneic bone marrow transfer in vivo impinged on the function of NKG2I, resulting in the enhanced colony formation in the spleen. NKG2I is a novel activating receptor mediating recognition and rejection of allogeneic target cells.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Bone Marrow Transplantation / immunology*
  • Gene Library
  • Graft Rejection / immunology*
  • Killer Cells, Natural / immunology*
  • Mice
  • Mice, Inbred Strains
  • Mice, Nude
  • Molecular Sequence Data
  • NK Cell Lectin-Like Receptor Subfamily K
  • Rats
  • Rats, Inbred F344
  • Receptors, Immunologic / chemistry
  • Receptors, Immunologic / genetics*
  • Receptors, Immunologic / immunology*
  • Receptors, Natural Killer Cell
  • T-Lymphocytes / immunology
  • Transplantation, Homologous


  • Klrk1 protein, mouse
  • NK Cell Lectin-Like Receptor Subfamily K
  • Receptors, Immunologic
  • Receptors, Natural Killer Cell

Associated data

  • GENBANK/AF306663