title: Interleukin-5 production by peripheral blood mononuclear cells of asthmatic patients is suppressed by T-440: relation to phosphodiesterase inhibition.
abstract: The effect of T-440, a selective type IV phosphodiesterase inhibitor, on cytokine production by peripheral blood mononuclear cells (PBMC) of atopic asthmatics was investigated. T-440 suppressed allergen-induced interleukin (IL)-5 production with a high potency (IC50 = 0.039 microgram/ml) and allergen-induced proliferation of PBMC (IC50 = 0.30 microgram/ml). T-440 also suppressed IL-2, IL-4 and IL-5 production by concanavalin A-activated PBMC in concentration-dependent manner. The IC50 values for the suppression of cytokine synthesis were 0.11 microgram/ml for IL-2, 0.57 microgram/ml for IL-5 and 7.7 micrograms/ml for IL-4. cAMP-elevating agents, such as PGE2, forskolin and dibutyryl cAMP, suppressed IL-2, IL-4 and IL-5 production by concanavalin A-stimulated PBMC in a manner similar to that of T-440. T-440 inhibited cAMP-phosphodiesterase activity and raised the intracellular cAMP level of PBMC in a concentration-dependent manner, suggesting that the increase of intracellular cAMP caused by T-440 results in the reduction of cytokine production. We conclude that T-440 suppressed cytokine production by peripheral T lymphocytes via the protein kinase A pathway and may be an effective modality to treat atopic diseases associated with eosinophilic inflammation.
authors.affiliation: Department of Medicine and Physical Therapy, University of Tokyo, Faculty of Medicine, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Kaminuma
authors.forename: A
authors.initials: A
authors.lastname: Mori
authors.forename: M
authors.initials: M
authors.lastname: Suko
authors.forename: H
authors.initials: H
authors.lastname: Kikkawa
authors.forename: K
authors.initials: K
authors.lastname: Ikezawa
authors.forename: H
authors.initials: H
authors.lastname: Okudaira
mesh_terms: D000328:Adult; D001249:Asthma / Q000276:immunology*; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D000242:Cyclic AMP / Q000032:analysis; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis*; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D011728:Pyridones / Q000494:pharmacology*
chemical_list: D007376:Interleukin-2; D015848:Interleukin-5; D009281:Naphthalenes; D010726:Phosphodiesterase Inhibitors; D011728:Pyridones; C101791:T 440; D003208:Concanavalin A; D015847:Interleukin-4; D000242:Cyclic AMP