Information Technology Reference
In-Depth Information
Chapter 8
Understanding the Immune System
by Computer-Aided Modeling
Massimo Bernaschi and Filippo Castiglione
Institute for Computing Applications (IAC), National Research Council (CNR), Viale del
Policlinico 137, 00161 Rome, Italy, m.bernaschi@iac.cnr.it and f.castiglione@iac.cnr.it
Abstract.
We describe some computer models of the immune system and in particular of its
response to the HIV infection. Then we introduce our model and show some results of simula-
tions of the AIDS disease progression.
8.1 Introduction
Recently the term “systems biology” started to become popular among scientists
working in the interdisciplinary field of theoretical biology. It suggests that to under-
stand biology we should examine the structure and the dynamics of the combined
system components rather than the isolated parts of a cell or organism (Kitano 2001).
Along this line some general properties of biological systems as adaptation, insensi-
tivity to specific parameters, and graceful degradation have been identified. It is
interesting to note that engineers routinely use similar concepts to describe the prop-
erties of mechanical or electric systems.
It is a relatively new field of science that involves the application of experi-
mental, theoretical, and modeling techniques to the study of biological organ-
isms at all levels, from the molecular, through the cellular, up to the behavioral
(Kitano 2001).
Such long-term goal, though well posed in scientific terms, appears quite ambi-
tious. On a more practical ground, the problems can be formulated in a narrower
context. For example, in the design of drugs, the objective is to find a synthetic
molecule that binds with high affinity a certain protein (or nucleic acid macromole-
cule) and either blocks its normal function or mimics another ligand for structures as
the receptors in order to induce a normal physiological response. Actually, this task
includes two distinct subproblems: the first one is to identify the molecules, the
second one is to understand the impact of the drug on the organism. Though not
independent, they can be addressed with different mathematical techniques and by
different expertise. As another example, consider the question to find the best schedule
