title: Molecular mechanisms underlying differential contribution of CD28 versus non-CD28 costimulatory molecules to IL-2 promoter activation.
abstract: T cell costimulation via CD28 and other (non-CD28) costimulatory molecules induces comparable levels of [(3)H]TdR incorporation, but fundamentally differs in the contribution to IL-2 production. In this study, we investigated the molecular basis underlying the difference between CD28 and non-CD28 costimulation for IL-2 gene expression. Resting T cells from a mutant mouse strain generated by replacing the IL-2 gene with a cDNA encoding green fluorescent protein were stimulated with a low dose of anti-CD3 plus anti-CD28 or anti-non-CD28 (CD5 or CD9) mAbs. CD28 and non-CD28 costimulation capable of inducing potent [(3)H]TdR uptake resulted in high and marginal levels of green fluorescent protein expression, respectively, indicating their differential IL-2 promoter activation. CD28 costimulation exhibited a time-dependent increase in the binding of transcription factors to the NF-AT and NF-kappaB binding sites and the CD28-responsive element of the IL-2 promoter, whereas non-CD28 costimulation did not. Particularly, a striking difference was observed for the binding of NF-kappaB to CD28-responsive element and the NF-kappaB binding site. Decreased NF-kappaB activation in non-CD28 costimulation resulted from the failure to translocate a critical NF-kappaB member, c-Rel, to the nuclear compartment due to the lack of IkappaBbeta inactivation. These observations suggest that unlike CD28 costimulation, non-CD28 costimulation fails to sustain IL-2 promoter activation and that such a failure is ascribed largely to the defect in the activation of c-Rel/NF-kappaB.
authors.affiliation: Department of Oncology, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Xu-Yu
authors.initials: XY
authors.lastname: Zhou
authors.forename: Yumi
authors.initials: Y
authors.lastname: Yashiro-Ohtani
authors.forename: Masakiyo
authors.initials: M
authors.lastname: Nakahira
authors.forename: Woong Ryeon
authors.initials: WR
authors.lastname: Park
authors.forename: Ryo
authors.initials: R
authors.lastname: Abe
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Hamaoka
authors.forename: Mayumi
authors.initials: M
authors.lastname: Naramura
authors.forename: Hua
authors.initials: H
authors.lastname: Gu
authors.forename: Hiromi
authors.initials: H
authors.lastname: Fujiwara
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000276:immunology; D018106:CD28 Antigens / Q000502:physiology*; D018956:CD5 Antigens / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology*; D020672:I-kappa B Proteins; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008817:Mice, Mutant Strains; D016328:NF-kappa B / Q000032:analysis / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011401:Promoter Regions, Genetic / Q000276:immunology*; D021381:Protein Transport / Q000276:immunology; D020569:Proto-Oncogene Proteins c-rel / Q000096:biosynthesis; D020218:Response Elements / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013936:Thymidine / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000096:biosynthesis; D014157:Transcription Factors / Q000096:biosynthesis; D014316:Tritium
chemical_list: D018106:CD28 Antigens; D018956:CD5 Antigens; D004268:DNA-Binding Proteins; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D007376:Interleukin-2; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D020569:Proto-Oncogene Proteins c-rel; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D014316:Tritium; D013936:Thymidine