GA impairs the proliferation of stimulated CD4+T cells. CD4+ T cells were assayed for effects of GA on their (a) viability, and (b, c) stimulation-induced proliferation. (a) CD4+ T cells (5×105) were supplemented with rhIL-2 (20 U/ml), seeded in triplicates, and aliquots were treated with 0.1 μM GA. After 48 h, viability was assessed by MTT assay. Viability of untreated cells was arbitrarily set to 100%. Data represent means ± SEM of two independent experiments. (b, c) CD4+ T cells (105) were stimulated (b) by allogenic MO-DCs (2×104) at unstimulated (-) or stimulated state (stim), and (c) by anti-CD3 (1 μg/ml) plus anti-CD28 antibodies (0.5 μg/ml). T cell proliferation was determined by incorporation of [3H] thymidine for the last 16 h of culture. Data represent the means ± SEM of three independent experiments each. Statistical significance: (b) *versus unstimulated MO-DCs, $versus stimulated MO-DCs without GA, (c) *versus unstimulated T cells, $versus stimulated T cells without GA (**,$$P < 0.01, ***,$$$P < 0.01).