Figure 6: Effect of GHCer on the upregulation of ID3 and Egr2/3-mediated increase of E3-ubiquintin ligases during T cell activation. CD4+ T cells isolated from mouse spleen were incubated with GHCer, ceramide or medium control for 24 hrs, and then activated by anti-CD3- and CD28 mAbs. At 2 and 12 hrs, total RNA was extracted for quantitation of ID3 (A), Itch (B), Egr2 (C), Egr3 (D), Cbl-b (E) by real-time quantitative PCR. The mRNA levels were normalized to the level of β-actin and compared to resting cells. The data are presented as mean ± SD of triplicate determinations. *, p<0.05, compared with medium control.