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this can be notice when comparing figures 6 to 7, 8 and 9. Inspection of figure 7
reveals that the regulatory cytokine absorption is nearly zero for the first 3 iter-
ations, intersecting the absorption cytokine absorption curve around iteration 6.
6Con lu on
In this paper, a model for the control of an immune response, based on regula-
tory cells and cytokines, was presented. Althought based on relatively simple and
arbitrary functions, the model simulation has lead to interesting results, with an
expected response characteristic obtained. Therefore, this model can be consid-
ered as an initial validation to the hypothesis that has lead to its development,
that the same cytokine that stimulates the immune system, upon initiation of
an immune response, can eventually lead to the downregulation of this response,
if the secreted cytokine affects more than one cell type, with different anities.
However, there are some points that need further investigation, such as a
mathematical explanation for the oscillatory response obtained for some model
parameters, and the influence of antigen dynamics and persistence in the system.
In addition, the model should take cell clonning and movement into consider-
ation, two aspects not considered in the simple simulation presented. In this
sense, this paper can be thought of as only an starting point for the simulation
of more complicated and accurate scenarios.
Acknowledgements
The authors wish to thank the reviewers for the insightful comments and sug-
gestions. This research was sponsored by UOL (www.uol.com.br), through its
UOL Bolsa Pesquisa program, process number 200503301636a. Besides, the au-
thors would like to thank the financial support by PQI/CAPES, CNPq and
FAPEMIG.
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