Randomness and pattern scale in the immune network

The immune system is a beautiful example of a complex information processing system. The complexity of the immune system is comparable to that of the nervous system. Both systems are comprised of a large number of different cell types communicating via the production of stimulatory or inhibitory molecules. Several of these cell types form connected networks of billions of different nodes. In the neural network the nodes are fixed and communicate via electrical signals; in the immune system the nodes recirculate and communicate via molecules (e. g. , antibody) or cell-to-cell contacts. An important property of both systems is "learning". During its early life the immune system learns to discriminate between self and nonself. Additionally, the immune system has a form memory which is known as "immunity": secondary immune responses are usually different from primary responses.