 This is hardly a simple topic.In his 1976 text "Immunology, Aging and Cancer" immunologist and Nobel Prize winner Sir Frank Macfarlane Burnet speculated that the immune system might one day be found to be as complex as the nervous system.As the production of lymphocytes is so close to the central role of the immune response it is wise to approach the study of it with some humility in the face of the task, although there are general principles that help in understanding.