title: The inhibitory leukocyte-associated Ig-like receptor-1 (LAIR-1) is expressed at high levels by human naive T cells and inhibits TCR mediated activation.
abstract: Human leukocyte-associated Ig-like receptor-1 (LAIR-1) is a transmembrane glycoprotein with a single extracellular Ig-like domain and a cytoplasmic tail containing two immunoreceptor tyrosine-based inhibition motifs (ITIMs). It is constitutively expressed on the majority of human mononuclear leukocytes and functions as an inhibitory receptor. In this study, we show that freshly isolated peripheral blood T cells are heterogeneous in their expression levels of LAIR-1. We have found that naive T cells express the highest levels of LAIR-1, even more than memory cells. The cross-linking of LAIR-1 inhibits T cell receptor (TCR) mediated signals in freshly isolated human naive T cells and whole populations of CD4+ or CD8+ T cells. TCR cross-linking increased cell surface expression of LAIR-1 in a process that requires p38 MAP kinase and ERK signaling. Altogether, these results indicate that LAIR-1 is capable of negatively regulating T cell functions, and its high level of expression by naive T cells suggests that it may function at an early stage in the development of an immune response.
authors.affiliation: Receptor Cell Biology Section, Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Twinbrook II, 12441 Parklawn Drive, Rockville, MD 20852, USA. Fborrego@niaid.nih.gov
authors.forename: Kerima
authors.initials: K
authors.lastname: Maasho
authors.forename: Madhan
authors.initials: M
authors.lastname: Masilamani
authors.forename: Robert
authors.initials: R
authors.lastname: Valas
authors.forename: Simana
authors.initials: S
authors.lastname: Basu
authors.forename: John E
authors.initials: JE
authors.lastname: Coligan
authors.forename: Francisco
authors.initials: F
authors.lastname: Borrego
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D045744:Cell Line, Tumor; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D051379:Mice; D011948:Receptors, Antigen, T-Cell / Q000037:antagonists & inhibitors* / Q000276:immunology; D011971:Receptors, Immunologic / Q000096:biosynthesis* / Q000276:immunology; D013601:T-Lymphocytes / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D005419:Flavonoids; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; C108073:leukocyte-associated immunoglobulin-like receptor 1; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium