Figure 5.

Effects of dexamethasone on ICOS expression after T cell activation. (a) Peripheral blood T cells from patients with inactive SLE (n = 4) and normal control individuals (n = 5) were cultured with ICOS co-stimulation for 48 or 72 hours in the presence or absence of 10^-6 mol/l dexamethasone and were analyzed using three-colour staining (anti-CD3-PerCP, anti-CD45RO-PE, biotinylated JTA009 plus streptavidin-FITC) and flow cytometry for ICOS expression. ICOS co-stimulation significantly induced ICOS expression on CD3⁺CD45RO⁺ T cells in both patients with inactive SLE and normal control individuals (dotted columns). Dexamethasone at 10^-6 mol/l almost completely abrogated the induction of ICOS after ICOS co-stimulation (hatched columns). The Y-axis showes percentages of ICOS⁺ cells among CD3⁺CD45RO⁺ cells. (b) Normal peripheral blood T cells (n = 4) were cultured with ICOS co-stimulation for 48 or 72 hours in the presence or absence of 10^-6 mol/l dexamethasone and were analyzed using two-color staining (left panel, anti-CD3-FITC and anti-CD25-PE; right panel, anti-CD3-FITC and anti-CD69-PE) and flow cytometry. *P < 0.05 versus before stimulation, by Wilcoxon rank sum test. #P < 0.05 versus without dexamethasone, by Wilcoxon rank sum test. DEXA, dexamethasone; FITC, fluorescein isothiocyanate; ICOS, inducible co-stimulator; NC, normal control; PE, phycoerythrin; PerCP, peridinin chlorophyll protein; SLE, systemic lupus erythematosus.