The Immune System in an Evolutionary Perspective

There are two reasons why the evolution of the immune system is an important question for theoretical immunology. Firstly, it is a fascinating subject in its own right; and whether we are theoreticians or experimentalists, we can hardly claim to be true biologists if we have no knowledge of the evolutionary origin of the system we are studying. Secondly, a major requirement for effective theoretical modelling of the immune system lies in the judicious choice of radical simplifications which nevertheless grasp essential features of the system. A consideration of evolution is a tool in this direction: when the immune sytem first appeared, it presumably existed in a relatively simple “primordial” form which we might be able to take as the basis for a simplified model.