Effect of reserpine on the Treg-dependent suppression of mitogen-induced Teff proliferation. Cells were incubated for 48 hours alone (□) or in the presence of 10 μg/mL PHA (▪). Each column is the mean ± SEM of 5 separate experiments. *P < .01 versus Teffs + PHA; #P < .01 versus Teffs + Tregs + PHA; §P < .05 versus Teffs + Tregs + PHA + reserpine.