FIG. 2.

Expression levels of activation markers following stimulation with various concentrations of prostratin. Highly purified quiescent T cells were cultured in the presence of the indicated concentrations of prostratin alone (A), prostratin plus anti-CD3 (B), and prostratin plus costimulation with anti-CD3 and anti-CD28 (C). Following 2 days in culture, cells were stained and analyzed as described in Materials and Methods. The cells used for this experiment were the same as those used for the experiment illustrated in Fig. 1, and results are representative of three experiments.