The Central and the Peripheral Immune Systems: What is the Relationship

Abstract

This chapter discusses the concept according to which the immune system is composed of two distinct compartments, a Central Immune System (CIS) and a Peripheral Immune System (PIS). The PIS is composed of disconnected lymphocyte clones which remain in a resting state unless they are specifically activated by an antigen giving rise to a classical immune response. The CIS is composed of a network of clones which display autonomous activity and integrates antigens into its ongoing regulatory dynamics. Functionally, the PIS is appropriate for reactions to immunizing antigens, whereas the CIS is appropriate for body antigens. Second generation immune network (SGIN) Models are systematically reviewed; we concluEn that they are unable to account satisfactorily for the CIS/PIS distinction. A third generation immune network Model, incorporating B-T cell co-operation, is able to accommodate both the structural and the functional properties of CIS and PIS in a coherent account, and moreover to explain how the CIS/PIS distinction can be generated by the self-organizing properties of the network. Finally, we emphasize that the difficulty in establishing a productive relationship between theory and experiment is a hallmark of the whole network approach to the immune system, and is perhaps the reason why, at the present time, the immunological community regards idiotypic networks with skepticism.