title: Interleukin-4 inhibits cyclo-oxygenase-2 expression and prostaglandin E production by human mature dendritic cells.
abstract: Interleukin-4 (IL-4) is considered the key cytokine for inducing T helper type 2 (Th2) cell differentiation, while interferon-gamma and IL-12 are pivotal cytokines for Th1 immune responses. Paradoxically, IL-4 has also been demonstrated to enhance IL-12 production by dendritic cells, suggesting an IL-4-dependent regulatory feedback of the Th1/Th2 system. In addition, prostaglandin E(2) (PGE(2)), a lipid mediator of inflammation, has been implicated in the enhancement of Th2-type responses acting directly on T and B lymphocytes. PGE(2) synthesis is dependent on the serial engagement of various enzymes, among which the inducible cyclo-oxygenase-2 (COX-2) exerts a critical role in monocytes and dendritic cells. In this study we demonstrate that IL-4 inhibits COX-2 gene expression and consequently prevents secretion of PGE(2) by mature human dendritic cells. We also show that PGE(2) does not regulate IL-12 and IL-10 production by dendritic cells in an autocrine fashion. Hence, we suggest that IL-4 may exploit an IL-12-independent regulatory feedback of the Th1/Th2 system through PGE(2) inhibition.
authors.affiliation: Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Raffaela
authors.initials: R
authors.lastname: Teloni
authors.forename: Federico
authors.initials: F
authors.lastname: Giannoni
authors.forename: Paolo
authors.initials: P
authors.lastname: Rossi
authors.forename: Roberto
authors.initials: R
authors.lastname: Nisini
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Gagliardi
mesh_terms: D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000235:genetics; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015854:Up-Regulation / Q000276:immunology
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D011994:Recombinant Proteins; D018664:Interleukin-12; D015847:Interleukin-4; D051546:Cyclooxygenase 2; D015232:Dinoprostone