Anti-idiotype antibodies that carry an internal image of an antigen epitope (Ab2 beta antibodies) can be used in vaccine preparations to favourably manipulate the immune network. These vaccines have been shown to induce protective immunity in animals that have not been intentionally exposed to the native antigen epitope. This review attempts to define certain theoretical and practical aspects of immunological network manipulations and their relevance to Ab2 beta internal image anti-idiotype antibody vaccine design.