In 1972, Gerald Edelman (b. 1929) received the Nobel Prize in Physiology or Medicine for his discovery of somatic selection in the immune system of mammals. It was his answer to the question of how our bodies manage to produce so many different antibodies, each geared against a particular invader.
Previously, it had been thought that the blueprints of all antibodies were encoded somewhere and were activated during an infection. But the number of all possible infectious agents that our species has encountered in the past and may yet encounter in the future is so staggering that this assumption strained credulity. Moreover, different people produced very different antibodies in response to the same invader.
Gerald Edelman showed that the immune system works by the evolutionary principle. While any other cell in the body carries the same genes, certain immune cells are an exception to the rule. Their genetic composition allows variation. When a new infectious agent is encountered, the immune ’s engine guns itself into a frenzy, busily trying different combinations of immune cells’ genes, until a fit is made.