The effect of ZA on CD4+ lymphocyte proliferation. (A) Isolated lymphocytes were labeled with CFSE, cultured in medium with or without 10 μM ZA and sensitized with anti-CD3 and anti-CD28 antibodies. (B) CD4+ lymphocyte proliferation curves were measured based on the percentage of cells with decreased fluorescence as compared to non-proliferating cells (0.4% at day 1). Data represent the mean values ± SEM and results from three independent experiments are shown. (TIF 134 kb