Figure 3.

Antigen dose and timing regulate CD154 expression of porcine CD4⁺ T cells. (A) Superantigen [staphylococcal Enterotoxin B (SEB)] expanded T cells were restimulated with autologous monocyte-derived dendritic cell (MoDC) for 5 h in the absence (left plot) or presence of varying concentrations of SEB (0.001–1 µg/ml) and assessed intracellularly for CD154 expression of proliferating CD4⁺ T cells according to gating strategy of Figure 2B. (B) As control, SEB expanded T cells were confronted with 1 µg/ml SEB in the absence of MoDC. (C) Candida albicans antigen expanded T cells were restimulated for 6 h with MoDC that were primed with varying concentrations of C. albicans antigen (2.5–40 µg/ml) or left unprimed (left plot). Representative plots for two independent titration experiments are shown. (D) Time course of CD154 expression after restimulating SEB-expanded cells with MoDC in the presence of 1 µg/ml SEB (0–8 h). Representative plots from n = 3 pigs are shown and summarized in panel (E). (F) Time course of CD154 expression following restimulation of C. albicans-expanded cells with C. albicans antigen-primed MoDC for 0–8 h. Representative plots from n = 3 pigs are shown and summarized in panel (G). Data in panels (E,G) are presented as mean ± SEM of CD154⁺ T cells over time (for data points lacking error bars, SEM values are smaller than circles representing means).