Figure 2. IL-2 receptor and IL-7 receptor competition.(A ) FACS plot showing the binding of IL-2-FITC (or unlabeled IL-2) to the Treg surface in the absence of IL-7 (left). Graph showing the binding of IL-2-FITC in the presence of increasing concentrations of IL-7 (0-106 pg/ml) (right). (B ) FACS plot showing the binding of IL-7-FITC (or unlabeled IL-7) to the Treg surface in the absence of IL-2 (left). Graph showing the binding of IL-7-FITC in the presence of increasing concentrations of IL-2 (0-104 UI/ml) (right).(C ) Flow cytometric assay to measure the association of CD25 and CD132 using beads. CD127 was linked to antimouse IgG1-coupled beads through a mouse-IgG1–anti-CD25 PE complex. CD132 association was determined by a biotinylated anti-CD132 and streptavidin APC. FACS plots shows the fluorescence of CD132 APC on beads alone (left), beads incubated with cell lysate from Treg incubated in PBS (center) and beads incubated with 104 pg/ml of IL-7. Graph shows the fluorescence of CD132 APC on beads incubated with increasing concentrations of IL-7 (0-106 pg/ml).