Fig. 2.

Inhibition of CD25 expression on activated CD4⁺ T cells by Br is time dependent. CD4⁺CD25⁻ T cells (1×10⁶) were stimulated in vitro with anti-CD3 (10 µg/ml) for 48 h. Activated T cells were removed from stimulation, washed thrice, and re-plated with or without Br 50 µg/ml or E64-inactivated Br, for up to 18 h. Representative dot plots of activated T cells at 3, 6, and 18 h of incubation are shown. There was no difference in surface expression of CD25 on control (68%) and Br treated (72%) CD4⁺ T cells at 3 h. A considerable reduction in CD25 expression was observed at 6 h (54% vs 11%) and 18 h (43% vs 5%) between activated controls and Br treated cells, which was largely abrogated with E64. Experiments were carried out in duplicate. CD4⁺ T cells (x-Axis) are compared to CD25 expression (y-Axis).