FIG. 6.

Effects of NMMA on STF-mediated suppression of TT-induced proliferative responses. PBMC were incubated with TT alone (2 μg/ml) or with STF (4 μg/ml) or STF plus l-arginine (L-arg.) in the absence (Media) or presence of NMMA (50 μM), and T-cell proliferation was determined. The data are shown as the mean percentage of suppression (standard deviation [SD]) of proliferation to TT in the presence of STF alone or with NMMA, an inhibitor of nitric oxide synthesis, at decreasing concentrations of l-arginine induced by PBMC from three different vaccinated volunteers.