The structure of the protein of the immunoglobulin antibody molecule includes two identical but variable binding domains and a common region. Genetic recombination provides essential diversity of antibodies and T-cell receptors. Clonal selection provides essential biological economy. Vaccines are pseudo-antigens which prime the immune system. The immune system sometimes does not differentiate well between 'self' and 'non- self' resulting in autoimmune diseases.
Allergies are an over-response of the immune system.
The response is limited by the T-8 suppresser cells . Information Processing in the Immune System Information in the immune system involves both the DNA based generic information and highly specific cell surface protein receptors . The system had to recognize an almost infinite number of different molecular structures as being antigenic. The system had to be economically sound and only mobilize a response to a current antigenic agent. A failure of this process can lead to auto-immune diseases.