Biphenotypic B/macrophage cells express COX-1 and up-regulate COX-2 expression and prostaglandin E sub(2) production in response to proinflammatory signals

B/macrophage cells are biphenotypic leukocytes of unknown function that simultaneously express B lymphocyte (IgM, IgD, B220, CD5) and macrophage (phagocytosis, F4/80, Mac-1) characteristics. B/macrophage cells can be generated from purified mouse B lymphocytes incubated in fibroblast-conditioned med...

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Bibliographic Details
Published in:European journal of immunology 1999-11, Vol.29 (11), p.3793-3803
Main Authors: Graf, BA, Nazarenko, DA, Borrello, MA, Roberts, L J, Morrow, J D, Palis, J, Phipps, R P
Format: Article
Language:English
Subjects:
COX-1 protein
prostaglandin E2
prostaglandin H synthase 1
prostaglandin H synthase 2
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Summary:B/macrophage cells are biphenotypic leukocytes of unknown function that simultaneously express B lymphocyte (IgM, IgD, B220, CD5) and macrophage (phagocytosis, F4/80, Mac-1) characteristics. B/macrophage cells can be generated from purified mouse B lymphocytes incubated in fibroblast-conditioned medium. A potential role for B/macrophage cells in inflammation was shown by their ability to express prostaglandin H synthase-1 (COX-1) and prostaglandin H synthase-2 (COX-2) and by their production of prostaglandin (PG) E sub(2). COX-1 and COX-2 mRNA expression is not observed in the precursor B lymphocytes and is not known to be a property of B lineage cells. In contrast, COX-2 and the prostanoids PGE sub(2), PGF sub(2 alpha ) and PGD sub(2) are highly inducible in B/macrophage cells upon stimulation with lipopoly-saccharide, CD40 ligand, or via engagement of surface IgM, supporting a role for these cells in inflammation. PGD sub(2) and its metabolites are of interest because they activate the nuclear receptor PPAR gamma that regulates lipid metabolism. The B/macrophage represents the first instance of a normal B-lineage cell capable of expressing COX-2. Importantly, B/macrophage cells were identified in vivo, providing evidence that they may play a significant role in immune responses. Since PGE sub(2) blunts IL-12 production, its synthesis by B/macrophage cells may shift the balance of an immune response towards Th2 and humoral immunity.
ISSN:0014-2980
DOI:10.1002/(SICI)1521-4141(199911)29:11<3793::AID-IMMU3793>3.0.CO;2-3