title: Co-expression of two LTB4 receptors in human mononuclear cells.
abstract: Leukotriene B4 (LTB4) is one of the most potent chemoattractants and activators of leukocytes, and is involved in inflammatory diseases. Two G-protein-coupled-receptors for LTB4, BLT1 and BLT2, have been isolated, and shown to be a high- and low-affinity receptor, respectively. The tissue distributions of these receptors are different, and distinct roles of each receptor remain elusive. We compared the expression of these two receptors using semi-quantitative PCR analyses, and show that these two receptors are expressed in various subsets of human lymphocytes in different quantities. BLT1 expression is highest in CD14+ monocytes, while BLT2 expression is high in CD8+ cytotoxic T-, CD4+ helper T-, and CD19+ B-cells. Moreover, BLT2 expression in these lymphocytes decreased upon activation of the cells. We also established CHO cells stably expressing both receptors, and found that these cells could migrate toward LTB4 with a broad range of LTB4. These findings suggest novel roles of LTB4 in immune system, and the biological significance of high- and low- affinity LTB4 receptors in chemotaxis.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yokomizo
authors.forename: T
authors.initials: T
authors.lastname: Izumi
authors.forename: T
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D016466:CHO Cells; D002633:Chemotaxis; D003208:Concanavalin A / Q000494:pharmacology; D006224:Cricetinae; D017931:DNA Primers / Q000737:chemistry; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D007975:Leukotriene B4 / Q000235:genetics / Q000378:metabolism*; D008213:Lymphocyte Activation; D016131:Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D010835:Phytohemagglutinins / Q000494:pharmacology; D010920:Placenta / Q000378:metabolism; D011043:Pokeweed Mitogens / Q000494:pharmacology; D018102:Receptors, Leukotriene B4 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D015703:Antigens, CD; D017931:DNA Primers; C485878:LTB4R2 protein, human; D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D018102:Receptors, Leukotriene B4; D003208:Concanavalin A; D007975:Leukotriene B4