title: CD40 engagement induces monocyte procoagulant activity through an interleukin-10 resistant pathway.
abstract: Interactions between membrane-bound molecules were previously shown to be involved in the induction of tissue factor-dependent monocyte procoagulant activity (PCA) by activated T cells. To investigate the potential role of the CD40/CD40 ligand (CD40L) pathway in this process, we first determined the effects of blocking anti-CD40 or anti-CD40L monoclonal antibodies (mAb) on the development of monocyte PCA during mixed lymphocyte reaction (MLR) between allogeneic peripheral blood mononuclear cells (PBMC). The strong inhibitory effect exerted by both mAb (mean percentages of inhibition: 88 and 91% for anti-CD40 and anti-CD40L mAb, respectively) indicates that CD40/CD40L interactions are required for the induction of PCA in MLR. These data led us to measure monocyte PCA after incubation of PBMC or purified monocytes with a stimulating anti-CD40 mAb (BL-C4) or with 3T6 fibroblasts transfected with the gene encoding CD40L. In both systems, we found that CD40 engagement strongly induced monocyte PCA which was related to tissue factor expression as shown by flow cytometric analysis. Finally, we observed that recombinant interleukin (IL)-10, which inhibits lipopolysaccharide-induced PCA, did not significantly influence CD40-dependent PCA. We conclude that CD40 engagement on monocytes induces tissue factor-dependent PCA through an IL-10-resistant pathway. These findings have implications for the control of coagulation events triggered by interactions between T cells and monocytes.
authors.affiliation: Laboratory of Hematology, Hôpital Erasme, Université Libre de Bruxelles, Belgium.
authors.forename: O
authors.initials: O
authors.lastname: Pradier
authors.forename: F
authors.initials: F
authors.lastname: Willems
authors.forename: D
authors.initials: D
authors.lastname: Abramowicz
authors.forename: L
authors.initials: L
authors.lastname: Schandené
authors.forename: M
authors.initials: M
authors.lastname: de Boer
authors.forename: K
authors.initials: K
authors.lastname: Thielemans
authors.forename: P
authors.initials: P
authors.lastname: Capel
authors.forename: M
authors.initials: M
authors.lastname: Goldman
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D001779:Blood Coagulation Factors / Q000096:biosynthesis* / Q000187:drug effects*; D019013:CD40 Antigens / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology*; D023201:CD40 Ligand; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D016753:Interleukin-10 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D007959:Lymphocyte Culture Test, Mixed; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; D001779:Blood Coagulation Factors; D019013:CD40 Antigens; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C045071:leukocyte procoagulant activity; D016753:Interleukin-10; D023201:CD40 Ligand