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Histamine downregulates monocyte CCL2 production through the histamine H4 receptor
Dorothea Dijkstra, MSc, Rob Leurs, PhD, Paul Chazot, PhD, Fiona C. Shenton, MSc, Holger Stark, PhD, Thomas Werfel, MD, Ralf Gutzmer, MD Journal of Allergy and Clinical Immunology Volume 120, Issue 2, Pages (August 2007) DOI: /j.jaci Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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Fig 1 The H4R is expressed by monocytes and upregulated by IFN-γ. A, Staining of monocytes with H4R (solid, thick line), isotype (dotted line), and blocked H4R antibody (solid, thin line). B, H4R protein expression after 48 hours' incubation with different ligands. Averages and SDs of 3 experiments are shown (statistical test: ANOVA). NS, Nonstimulated cells. Journal of Allergy and Clinical Immunology , DOI: ( /j.jaci ) Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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Fig 2 Histamine, 10−5 mol/L, induces calcium mobilization in monocytes through the H4R. JNJ at 10−5 mol/L blocks this effect. Injection of the ligands was at a time of 5 seconds (arrows), and FLUO-4 fluorescence was measured for 40 seconds. A representative of 3 experiments is shown. Journal of Allergy and Clinical Immunology , DOI: ( /j.jaci ) Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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Fig 3 A, Dose dependency of CCL2 downregulation by histamine (HA), clobenpropit (Clob), and 4-methylhistamine (4-MH). B, Inhibition of CCL2 production is blocked by JNJ C, Absolute CCL2 production at different incubation times. Data are normalized to nonstimulated (NS) values in Fig 3, A and B. Averages and SEMs (Fig 3, A), SDs (Fig 3, B), and SEMs (Fig 3, C) of at least 3 experiments are shown (statistical test: ANOVA). Journal of Allergy and Clinical Immunology , DOI: ( /j.jaci ) Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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Fig 4 CCL2 mRNA synthesis is downregulated through histamine (HA) and the H4R agonists clobenpropit (Clob) and 4-methylhistamine (4-MH). Averages and SEMs of 6 experiments are shown (statistical test: ANOVA). Journal of Allergy and Clinical Immunology , DOI: ( /j.jaci ) Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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Fig 5 CD14 staining to determine the monocyte fraction within adherent cells (A). Effect of 4-methylhistamine (4-MH, thick solid line) on intracellular CCL2 after 4 hours (B) and 48 hours (C) of incubation. Thin solid line, Nonstimulated cells (NS); filled section, isotype. A representative experiment and averages of normalized mean intracellular CCL2 fluorescence values and SEMs of 5 experiments are shown (statistical test: paired t test). Journal of Allergy and Clinical Immunology , DOI: ( /j.jaci ) Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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Fig 6 The supernatants of H4R agonist–stimulated monocytes induce less chemotaxis of monocytes. Values are normalized to chemotaxis induced by supernatants from nonstimulated monocytes (NS). Histamine (HA), clobenpropit (Clob), and 4-methylhistamine (4-MH; all 10−5 mol/L) and CCL2-neutralizing antibody (a-CCL2) are shown. Averages and SEMs of 4 experiments are shown (statistical test: ANOVA). Journal of Allergy and Clinical Immunology , DOI: ( /j.jaci ) Copyright © 2007 American Academy of Allergy, Asthma & Immunology Terms and Conditions
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