Figure 2

Dynamic simulation of the T-helper regulatory network, in the presence of IL-4. The plot provided by SQUAD displays the behavior of each component of the network according to time. The values range between 0 (inactive) and 1 (active). Time 0 indicates the time of addition of IL-4 to the network in the Th0 state. In addition to the plot display, SQUAD provides a dynamic network display (top panel) in which the nodes are colored in real-time according to the activation level from white (completely inactive) to black (completely active). The three top images are snapshots of the network at different time points. At Time 0 the network is in the Th0 and and a pulse of IL-4 is added to the system. The pulse originates a transitory state of activation (Time 2.6 is shown), which eventually leads the system to steady state representing the Th2 state (Time 6 and onwards). Time is expressed in arbitrary units.