FIG. 5.

CD4⁺ T cells are the main lymphocyte subset responsive to PFR. Representative histograms show frequencies of various T-cell populations in PBMC of Chagas' disease patients after 20 h of culture with either PFR, EPI-Ag, or medium alone. Frequencies of cells expressing the indicated surface markers were determined by using antibodies directly conjugated with either PE (y axis) or FITC (x axis) as described in Materials and Methods. Top left histogram represents forward- and side-scatter gates for R1 (small lymphocytes) and R2 (large lymphocytes).