Molecular Mechanisms Underlying Differential Contribution of CD28 Versus Non-CD28 Costimulatory Molecules to IL-2 Promoter Activation

• Published in: The Journal of immunology (1950) 2002-04, Vol.168 (8), p.3847-3854
• Main Authors: Zhou, Xu-Yu, Yashiro-Ohtani, Yumi, Nakahira, Masakiyo, Park, Woong Ryeon, Abe, Ryo, Hamaoka, Toshiyuki, Naramura, Mayumi, Gu, Hua, Fujiwara, Hiromi
• Format: Article
• Language: English
• Subjects: Animals; Binding Sites - immunology; c-Rel protein; CD28 antigen; CD28 Antigens - physiology; CD5 Antigens - physiology; Cell Nucleus - metabolism; Cells, Cultured; DNA-Binding Proteins - antagonists & inhibitors; DNA-Binding Proteins - biosynthesis; DNA-Binding Proteins - metabolism; Female; Gene Expression Regulation - immunology; I-kappa B Proteins; Interleukin-2 - biosynthesis; Interleukin-2 - genetics; Interleukin-2 - metabolism; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Mice, Mutant Strains; NF-kappa B - analysis; NF-kappa B - antagonists & inhibitors; NF-kappa B - biosynthesis; NF-kappa B - metabolism; NFATC Transcription Factors; Nuclear Proteins; Promoter Regions, Genetic - immunology; Protein Transport - immunology; Proto-Oncogene Proteins c-rel - biosynthesis; Response Elements - immunology; T-Lymphocytes - immunology; Thymidine - metabolism; Transcription Factor AP-1 - biosynthesis; Transcription Factors - biosynthesis; Tritium
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.168.8.3847

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.