Modelling the Control of an Immune Response Through Cytokine Signalling - Artificial Immune Systems - page 20

Fig. 8. Cytokine secretion for effector cells 1 and 3
Fig. 9. Regulatory cell cytokine secretion and absorption
in figure 6 is that the initially stimulated effector cell is suppressed before cells
1 and 3, reaching, an activation level of 0.04 at iteration 14, exactly when cells
1 and 3 have reached peak values. This activation delay is due to the time taken
by the secreted cytokines to diffuse in the environment and reach nearby cells.
In addition, the cytokine activation and secretion data (figures 7, 8 and 9)
reveal interesting information. Cytokine secretion by the regulatory cell reaches
a peak value equals to 8, at iteration 13, while cytokine absorption is maintained
at low levels, never exceeding 0.2. Therefore, it is possible to conclude that regu-
latory cells, in this model, need a low absorption rate to terminate the response,
resulting in little environment disturbance when not suppressing effector cells.
Because the governing equation for cytokine secretion was chosen as directly
proportional to the activation level 8, both variables have the same waveforms;