title: Inhibition of interleukin-2 production in the human T cell line JURKAT by nonpolar maleimides.
abstract: The immunosuppressive properties of polar and nonpolar maleimides were studied by measuring their ability to inhibit mitogen-induced interleukin-2 (IL-2) production by JURKAT T cells. The nonpolar maleimides N-ethylmaleimide (NEM) and N-phenylmaleimide (NPM) inhibited IL-2 production by 85-99%, but only when added to JURKAT cells prior to the mitogen. The polar maleimides N-hydroxymaleimide (NHM) and 4-maleimidosalicylic acid (M84) did not suppress IL-2 production significantly, even though NHM reacted with more cellular thiols (12%) than did NPM (8%). Both NEM and NPM suppressed IL-2 production at doses that did not affect proliferation. NEM inhibited IL-2 production induced by PHA, anti-CD3 (alpha CD3) monoclonal antibodies or PMA, and A23187, but did not interfere with the binding of alpha CD3 to the cells. NEM inhibited IL-2 production at concentrations that did not interfere with the PHA-induced increase in intracellular free calcium [( Ca]i). Neither NPM nor NHM inhibited the rise in [Ca]i, even at the highest concentrations tested. Although JURKAT T cells require both PMA and A23187 to induce IL-2 production, we found that cells pretreated with PMA could respond to A23187 added 18 hr later. PMA-treated cells were not resistant to the immunosuppressive effects of NEM or NPM. However, PMA-pretreated cells became resistant to the inhibitory effects of NEM upon the addition of A23187, suggesting that nonpolar maleimides inhibit activation events induced by the rise in [Ca]i.
authors.affiliation: Department of Surgery, Albany Medical College, New York 12208.
authors.forename: B M
authors.initials: BM
authors.lastname: Freed
authors.forename: N
authors.initials: N
authors.lastname: Lempert
authors.forename: D A
authors.initials: DA
authors.lastname: Lawrence
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D002118:Calcium / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D005033:Ethylmaleimide / Q000633:toxicity*; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000187:drug effects*; D008301:Maleimides / Q000633:toxicity*; D010641:Phenotype; D010835:Phytohemagglutinins / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D008301:Maleimides; D010835:Phytohemagglutinins; D013438:Sulfhydryl Compounds; C028525:N-phenylmaleimide; D005033:Ethylmaleimide; D002118:Calcium