Kinetics of IL-13 and Tax expression during in vitro culture of PBMCs from HTLV-1-infected individuals. PBMCs prepared from a HAM/TSP patient (TW; top), an HTLV-1-positive asymptomatic carrier (HT; middle), and an HTLV-1-negative healthy control (NC; bottom) were stained and analyzed by flow cytometry as in Figure 4. PBMCs were stained and analyzed immediately after preparation (0 hour) or incubated in medium containing Brefeldin A and Concanamycin A for the time periods indicated at the top of the figure (6, 24, and 48 hours) prior to analysis. Fluorescence intensities of Tax (y-axis) and IL-13 (x-axis) are plotted for CD4⁺ T cells.