In vitro impacts of CRA on T cells. (A) T cells were cultured with CRA at the graded concentrations in the presence of Con A (●) or vehicle alone (○), and then examined ³H-thymidine uptake on day 4. (B) T cells were cultured in the presence of CRA at the graded concentrations with PMA plus ionomycin (●) or vehicle alone (○), followed by measuring ³H-thymidine uptake on day 2. The viability of these cells was evaluated by PI uptake in the presence of PMA plus ionomycin (▴) or vehicle alone (▵). (C) T cells were incubated with PMA plus ionomycin for 24 hours. After extensive washing, the T cells were cultured again with CRA at indicated concentrations with (●) or without IL-2 (○), and then examined ³H-thymidine uptake on day 2. (D) Cytokine concentrations were measured in the culture supernatants from T cells treated with (●) or without PMA plus ionomycin (○) in the presence of CRA at the indicated doses for 24 hours. (E) Surface expression of CD25, CD44, and CD69 on T cells was tested by flow cytometry. Data shown in this figure are the mean ± SD (n = 3). Asterisks indicate statistically significant (*P < .05; **P < .01) differences compared with the vehicle-treated control samples.