title: Prostaglandin E2 and dexamethasone inhibit IL-12 receptor expression and IL-12 responsiveness.
abstract: Regulation of the factors governing IL-12R expression and IL-12 responsiveness has been shown to be important in the generation and stability of Th1- and Th2-type responses. In this regard, cytokines have been shown to have a prominent role in regulating IL-12R expression. In this study, the role that PGE2 and dexamethasone (DXM) have in regulating IL-12R expression was evaluated. Addition of PGE2 or DXM to human PBMCs stimulated with immobilized anti-CD3 plus IL-12 inhibited the production of IFN-gamma in a dose-responsive manner. Moreover, PBMCs stimulated with immobilized anti-CD3 in the presence of PGE2 or DXM for 3 days, washed extensively, and restimulated in the presence of IL-12 still did not produce IFN-gamma. This lack of IL-12 responsiveness from cells cultured in either PGE2 or DXM was correlated with diminished surface expression of IL-12Rbeta1, IL-12Rbeta2 mRNA expression, and IL-12 binding. Finally, the PGE2- and DXM-mediated inhibition of IL-12R expression was not affected significantly by addition of neutralizing Abs against either IL-4, IL-10, or TGF-beta. By contrast, addition of dibutyryl cAMP, 8-bromoadenosine 3:5 cAMP (8-Br-cAMP), or cholera toxin substantially reduced IL-12R expression, suggesting that PGE2 may be mediating its effects through enhancement of cAMP.
authors.affiliation: Clinical Immunology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
authors.forename: C Y
authors.initials: CY
authors.lastname: Wu
authors.forename: K
authors.initials: K
authors.lastname: Wang
authors.forename: J F
authors.initials: JF
authors.lastname: McDyer
authors.forename: R A
authors.initials: RA
authors.lastname: Seder
mesh_terms: D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D015232:Dinoprostone / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D016753:Interleukin-10 / Q000494:pharmacology; D018664:Interleukin-12 / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation; D016853:Muromonab-CD3 / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects / Q000276:immunology; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics; D053707:Receptors, Interleukin-12; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D016853:Muromonab-CD3; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D018664:Interleukin-12; D015847:Interleukin-4; D003907:Dexamethasone; D007371:Interferon-gamma; D000242:Cyclic AMP; D015232:Dinoprostone