title: Thymus-dependent modulation of Ly49 inhibitory receptor expression on NK1.1+gamma/delta T cells.
abstract: Major histocompatibility complex (MHC) class I-specific inhibitory receptors are expressed not only on natural killer (NK) cells but also on some subsets of T cells. We here show Ly49 expression on gamma/delta T cells in the thymus and liver of beta2-microglobulin-deficient (beta2m-/-) and C57BL/6 (beta2m+/+) mice. Ly49C/I or Ly49A receptor was expressed on NK1.1+gamma/delta T cells but not on NK1.1-gamma/delta T cells. The numbers of NK1.1+gamma/delta T cells were significantly smaller in beta2m+/+ mice than in beta2m-/- mice with the same H-2b genetic background. Among NK1.1+gamma/delta T cells, the proportions of Ly49C/I+ cells but not of Ly49A+ cells, were decreased in beta2m+/+ mice, suggesting that cognate interaction between Ly49C/I and H-2Kb is involved in the reduction of the number of Ly49C/I+ gamma/delta T cells in beta2m+/+ mice. The frequency of Ly49C/I+ cells in NK1.1+gamma/delta T cells was lower in both lethally irradiated beta2m+/+ mice transplanted with bone marrow (BM) from beta2m-/- mice and lethally irradiated beta2m-/- mice transplanted with BM from beta2m+/+ mice than those in adult thymectomized BM-transplanted chimera mice. These results suggest that reduction of Ly49C/I+ NK1.1+gamma/delta T cells in beta2m+/+ mice is at least partly due to the down-modulation by MHC class I molecules on BM-derived haematopoietic cells or radioresistant cells in the thymus.
authors.affiliation: Laboratory of Host Defense & Germfree Life, Research Institute for Disease Mechanism & Control; First Department of Internal Medicine, Nagoya University School of Medicine, Nagoya 466-8550, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Hara
authors.forename: H
authors.initials: H
authors.lastname: Nishimura
authors.forename: Y
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikai
mesh_terms: D000818:Animals; D000941:Antigens / Q000032:analysis*; D000950:Antigens, Ly / Q000378:metabolism; D000954:Antigens, Surface / Q000378:metabolism; D016026:Bone Marrow Transplantation; D005260:Female; D037181:Lectins, C-Type; D008099:Liver / Q000276:immunology; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D055650:NK Cell Lectin-Like Receptor Subfamily A; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011506:Proteins / Q000032:analysis*; D011836:Radiation Tolerance; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis; D011971:Receptors, Immunologic / Q000378:metabolism*; D055630:Receptors, NK Cell Lectin-Like; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*; D018183:Transplantation Chimera / Q000276:immunology; D001613:beta 2-Microglobulin / Q000172:deficiency
chemical_list: D000941:Antigens; D000950:Antigens, Ly; D000954:Antigens, Surface; C527088:Klra1 protein, mouse; C527091:Klra3 protein, mouse; C527211:Klrb1c protein, mouse; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D055650:NK Cell Lectin-Like Receptor Subfamily A; D055651:NK Cell Lectin-Like Receptor Subfamily B; D011506:Proteins; D016692:Receptors, Antigen, T-Cell, gamma-delta; D011971:Receptors, Immunologic; D055630:Receptors, NK Cell Lectin-Like; D001613:beta 2-Microglobulin