Simulating the immune system

When a foreign substance (antigen) is introduced into our bodies, our immune system acts to eliminate that substance. This response is a complex process involving the collective and coordinated response of approximately 10/sup 12/ cells, which is comparable to the number of synapses in the human brain. In an effort to fit detailed experimental observations into a comprehensive model of the immune system, computer simulations are just beginning to play a role. The approach that we describe uses a modified cellular automaton (or lattice gas). Although our automaton is much more complex than the automata usually considered by mathematicians and is not subject to analytical analysis by presently known methods, it has several advantages over traditional ODE models.