Figure 7. Increased mitochondrial Ca2+ by IL-6 is required to sustain nuclear NFAT accumulation late during activation of CD4 cells.
(A) CD4 cells were activated in the presence or absence of IL-6 for 42 hr followed by 6 hr treatment with medium (Med) or CGP-37157 (CGP). NFATc2 (red) was examined by immunostaining and confocal microscopy. TOPRO was used as nuclear dye. 40× Magnification. Bars represent 20 μm. (B) CD4 cells were activated in the presence or absence of IL-6 for 42 hr. FK506 (FK) was added to culture for another 6 hr. Supernatants were collected, and IL-21 and IL-4 levels were measured by ELISA. (C) Relative mRNA for IL-21 and IL-4 levels in CD4 cells activated as in (B) was measured by RT-PCR. Error bars represent the mean ± SD. *denotes p < 0.05, as determined by two-way ANOVA test. Results are representative of 2–3 experiments.